/* auditsc.c -- System-call auditing support
 * Handles all system-call specific auditing features.
 *
 * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
 * Copyright 2005 Hewlett-Packard Development Company, L.P.
 * Copyright (C) 2005, 2006 IBM Corporation
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
 *
 * Many of the ideas implemented here are from Stephen C. Tweedie,
 * especially the idea of avoiding a copy by using getname.
 *
 * The method for actual interception of syscall entry and exit (not in
 * this file -- see entry.S) is based on a GPL'd patch written by
 * okir@suse.de and Copyright 2003 SuSE Linux AG.
 *
 * POSIX message queue support added by George Wilson <ltcgcw@us.ibm.com>,
 * 2006.
 *
 * The support of additional filter rules compares (>, <, >=, <=) was
 * added by Dustin Kirkland <dustin.kirkland@us.ibm.com>, 2005.
 *
 * Modified by Amy Griffis <amy.griffis@hp.com> to collect additional
 * filesystem information.
 *
 * Subject and object context labeling support added by <danjones@us.ibm.com>
 * and <dustin.kirkland@us.ibm.com> for LSPP certification compliance.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <asm/types.h>
#include <linux/atomic.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/socket.h>
#include <linux/mqueue.h>
#include <linux/audit.h>
#include <linux/personality.h>
#include <linux/time.h>
#include <linux/netlink.h>
#include <linux/compiler.h>
#include <asm/unistd.h>
#include <linux/security.h>
#include <linux/list.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/highmem.h>
#include <linux/syscalls.h>
#include <asm/syscall.h>
#include <linux/capability.h>
#include <linux/fs_struct.h>
#include <linux/compat.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <uapi/linux/limits.h>

#include "audit.h"

/* flags stating the success for a syscall */
#define AUDITSC_INVALID 0
#define AUDITSC_SUCCESS 1
#define AUDITSC_FAILURE 2

/* no execve audit message should be longer than this (userspace limits) */
#define MAX_EXECVE_AUDIT_LEN 7500

/* max length to print of cmdline/proctitle value during audit */
#define MAX_PROCTITLE_AUDIT_LEN 128

/* number of audit rules */
int audit_n_rules;

/* determines whether we collect data for signals sent */
int audit_signals;

struct audit_aux_data {
        struct audit_aux_data   *next;
        int                     type;
};

#define AUDIT_AUX_IPCPERM       0

/* Number of target pids per aux struct. */
#define AUDIT_AUX_PIDS  16

struct audit_aux_data_pids {
        struct audit_aux_data   d;
        pid_t                   target_pid[AUDIT_AUX_PIDS];
        kuid_t                  target_auid[AUDIT_AUX_PIDS];
        kuid_t                  target_uid[AUDIT_AUX_PIDS];
        unsigned int            target_sessionid[AUDIT_AUX_PIDS];
        u32                     target_sid[AUDIT_AUX_PIDS];
        char                    target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN];
        int                     pid_count;
};

struct audit_aux_data_bprm_fcaps {
        struct audit_aux_data   d;
        struct audit_cap_data   fcap;
        unsigned int            fcap_ver;
        struct audit_cap_data   old_pcap;
        struct audit_cap_data   new_pcap;
};

struct audit_tree_refs {
        struct audit_tree_refs *next;
        struct audit_chunk *c[31];
};

static int audit_match_perm(struct audit_context *ctx, int mask)
{
        unsigned n;
        if (unlikely(!ctx))
                return 0;
        n = ctx->major;

        switch (audit_classify_syscall(ctx->arch, n)) {
        case 0: /* native */
                if ((mask & AUDIT_PERM_WRITE) &&
                     audit_match_class(AUDIT_CLASS_WRITE, n))
                        return 1;
                if ((mask & AUDIT_PERM_READ) &&
                     audit_match_class(AUDIT_CLASS_READ, n))
                        return 1;
                if ((mask & AUDIT_PERM_ATTR) &&
                     audit_match_class(AUDIT_CLASS_CHATTR, n))
                        return 1;
                return 0;
        case 1: /* 32bit on biarch */
                if ((mask & AUDIT_PERM_WRITE) &&
                     audit_match_class(AUDIT_CLASS_WRITE_32, n))
                        return 1;
                if ((mask & AUDIT_PERM_READ) &&
                     audit_match_class(AUDIT_CLASS_READ_32, n))
                        return 1;
                if ((mask & AUDIT_PERM_ATTR) &&
                     audit_match_class(AUDIT_CLASS_CHATTR_32, n))
                        return 1;
                return 0;
        case 2: /* open */
                return mask & ACC_MODE(ctx->argv[1]);
        case 3: /* openat */
                return mask & ACC_MODE(ctx->argv[2]);
        case 4: /* socketcall */
                return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
        case 5: /* execve */
                return mask & AUDIT_PERM_EXEC;
        default:
                return 0;
        }
}

static int audit_match_filetype(struct audit_context *ctx, int val)
{
        struct audit_names *n;
        umode_t mode = (umode_t)val;

        if (unlikely(!ctx))
                return 0;

        list_for_each_entry(n, &ctx->names_list, list) {
                if ((n->ino != AUDIT_INO_UNSET) &&
                    ((n->mode & S_IFMT) == mode))
                        return 1;
        }

        return 0;
}

/*
 * We keep a linked list of fixed-sized (31 pointer) arrays of audit_chunk *;
 * ->first_trees points to its beginning, ->trees - to the current end of data.
 * ->tree_count is the number of free entries in array pointed to by ->trees.
 * Original condition is (NULL, NULL, 0); as soon as it grows we never revert to NULL,
 * "empty" becomes (p, p, 31) afterwards.  We don't shrink the list (and seriously,
 * it's going to remain 1-element for almost any setup) until we free context itself.
 * References in it _are_ dropped - at the same time we free/drop aux stuff.
 */

#ifdef CONFIG_AUDIT_TREE
static void audit_set_auditable(struct audit_context *ctx)
{
        if (!ctx->prio) {
                ctx->prio = 1;
                ctx->current_state = AUDIT_RECORD_CONTEXT;
        }
}

static int put_tree_ref(struct audit_context *ctx, struct audit_chunk *chunk)
{
        struct audit_tree_refs *p = ctx->trees;
        int left = ctx->tree_count;
        if (likely(left)) {
                p->c[--left] = chunk;
                ctx->tree_count = left;
                return 1;
        }
        if (!p)
                return 0;
        p = p->next;
        if (p) {
                p->c[30] = chunk;
                ctx->trees = p;
                ctx->tree_count = 30;
                return 1;
        }
        return 0;
}

static int grow_tree_refs(struct audit_context *ctx)
{
        struct audit_tree_refs *p = ctx->trees;
        ctx->trees = kzalloc(sizeof(struct audit_tree_refs), GFP_KERNEL);
        if (!ctx->trees) {
                ctx->trees = p;
                return 0;
        }
        if (p)
                p->next = ctx->trees;
        else
                ctx->first_trees = ctx->trees;
        ctx->tree_count = 31;
        return 1;
}
#endif

static void unroll_tree_refs(struct audit_context *ctx,
                      struct audit_tree_refs *p, int count)
{
#ifdef CONFIG_AUDIT_TREE
        struct audit_tree_refs *q;
        int n;
        if (!p) {
                /* we started with empty chain */
                p = ctx->first_trees;
                count = 31;
                /* if the very first allocation has failed, nothing to do */
                if (!p)
                        return;
        }
        n = count;
        for (q = p; q != ctx->trees; q = q->next, n = 31) {
                while (n--) {
                        audit_put_chunk(q->c[n]);
                        q->c[n] = NULL;
                }
        }
        while (n-- > ctx->tree_count) {
                audit_put_chunk(q->c[n]);
                q->c[n] = NULL;
        }
        ctx->trees = p;
        ctx->tree_count = count;
#endif
}

static void free_tree_refs(struct audit_context *ctx)
{
        struct audit_tree_refs *p, *q;
        for (p = ctx->first_trees; p; p = q) {
                q = p->next;
                kfree(p);
        }
}

static int match_tree_refs(struct audit_context *ctx, struct audit_tree *tree)
{
#ifdef CONFIG_AUDIT_TREE
        struct audit_tree_refs *p;
        int n;
        if (!tree)
                return 0;
        /* full ones */
        for (p = ctx->first_trees; p != ctx->trees; p = p->next) {
                for (n = 0; n < 31; n++)
                        if (audit_tree_match(p->c[n], tree))
                                return 1;
        }
        /* partial */
        if (p) {
                for (n = ctx->tree_count; n < 31; n++)
                        if (audit_tree_match(p->c[n], tree))
                                return 1;
        }
#endif
        return 0;
}

static int audit_compare_uid(kuid_t uid,
                             struct audit_names *name,
                             struct audit_field *f,
                             struct audit_context *ctx)
{
        struct audit_names *n;
        int rc;
 
        if (name) {
                rc = audit_uid_comparator(uid, f->op, name->uid);
                if (rc)
                        return rc;
        }
 
        if (ctx) {
                list_for_each_entry(n, &ctx->names_list, list) {
                        rc = audit_uid_comparator(uid, f->op, n->uid);
                        if (rc)
                                return rc;
                }
        }
        return 0;
}

static int audit_compare_gid(kgid_t gid,
                             struct audit_names *name,
                             struct audit_field *f,
                             struct audit_context *ctx)
{
        struct audit_names *n;
        int rc;
 
        if (name) {
                rc = audit_gid_comparator(gid, f->op, name->gid);
                if (rc)
                        return rc;
        }
 
        if (ctx) {
                list_for_each_entry(n, &ctx->names_list, list) {
                        rc = audit_gid_comparator(gid, f->op, n->gid);
                        if (rc)
                                return rc;
                }
        }
        return 0;
}

static int audit_field_compare(struct task_struct *tsk,
                               const struct cred *cred,
                               struct audit_field *f,
                               struct audit_context *ctx,
                               struct audit_names *name)
{
        switch (f->val) {
        /* process to file object comparisons */
        case AUDIT_COMPARE_UID_TO_OBJ_UID:
                return audit_compare_uid(cred->uid, name, f, ctx);
        case AUDIT_COMPARE_GID_TO_OBJ_GID:
                return audit_compare_gid(cred->gid, name, f, ctx);
        case AUDIT_COMPARE_EUID_TO_OBJ_UID:
                return audit_compare_uid(cred->euid, name, f, ctx);
        case AUDIT_COMPARE_EGID_TO_OBJ_GID:
                return audit_compare_gid(cred->egid, name, f, ctx);
        case AUDIT_COMPARE_AUID_TO_OBJ_UID:
                return audit_compare_uid(tsk->loginuid, name, f, ctx);
        case AUDIT_COMPARE_SUID_TO_OBJ_UID:
                return audit_compare_uid(cred->suid, name, f, ctx);
        case AUDIT_COMPARE_SGID_TO_OBJ_GID:
                return audit_compare_gid(cred->sgid, name, f, ctx);
        case AUDIT_COMPARE_FSUID_TO_OBJ_UID:
                return audit_compare_uid(cred->fsuid, name, f, ctx);
        case AUDIT_COMPARE_FSGID_TO_OBJ_GID:
                return audit_compare_gid(cred->fsgid, name, f, ctx);
        /* uid comparisons */
        case AUDIT_COMPARE_UID_TO_AUID:
                return audit_uid_comparator(cred->uid, f->op, tsk->loginuid);
        case AUDIT_COMPARE_UID_TO_EUID:
                return audit_uid_comparator(cred->uid, f->op, cred->euid);
        case AUDIT_COMPARE_UID_TO_SUID:
                return audit_uid_comparator(cred->uid, f->op, cred->suid);
        case AUDIT_COMPARE_UID_TO_FSUID:
                return audit_uid_comparator(cred->uid, f->op, cred->fsuid);
        /* auid comparisons */
        case AUDIT_COMPARE_AUID_TO_EUID:
                return audit_uid_comparator(tsk->loginuid, f->op, cred->euid);
        case AUDIT_COMPARE_AUID_TO_SUID:
                return audit_uid_comparator(tsk->loginuid, f->op, cred->suid);
        case AUDIT_COMPARE_AUID_TO_FSUID:
                return audit_uid_comparator(tsk->loginuid, f->op, cred->fsuid);
        /* euid comparisons */
        case AUDIT_COMPARE_EUID_TO_SUID:
                return audit_uid_comparator(cred->euid, f->op, cred->suid);
        case AUDIT_COMPARE_EUID_TO_FSUID:
                return audit_uid_comparator(cred->euid, f->op, cred->fsuid);
        /* suid comparisons */
        case AUDIT_COMPARE_SUID_TO_FSUID:
                return audit_uid_comparator(cred->suid, f->op, cred->fsuid);
        /* gid comparisons */
        case AUDIT_COMPARE_GID_TO_EGID:
                return audit_gid_comparator(cred->gid, f->op, cred->egid);
        case AUDIT_COMPARE_GID_TO_SGID:
                return audit_gid_comparator(cred->gid, f->op, cred->sgid);
        case AUDIT_COMPARE_GID_TO_FSGID:
                return audit_gid_comparator(cred->gid, f->op, cred->fsgid);
        /* egid comparisons */
        case AUDIT_COMPARE_EGID_TO_SGID:
                return audit_gid_comparator(cred->egid, f->op, cred->sgid);
        case AUDIT_COMPARE_EGID_TO_FSGID:
                return audit_gid_comparator(cred->egid, f->op, cred->fsgid);
        /* sgid comparison */
        case AUDIT_COMPARE_SGID_TO_FSGID:
                return audit_gid_comparator(cred->sgid, f->op, cred->fsgid);
        default:
                WARN(1, "Missing AUDIT_COMPARE define.  Report as a bug\n");
                return 0;
        }
        return 0;
}

/* Determine if any context name data matches a rule's watch data */
/* Compare a task_struct with an audit_rule.  Return 1 on match, 0
 * otherwise.
 *
 * If task_creation is true, this is an explicit indication that we are
 * filtering a task rule at task creation time.  This and tsk == current are
 * the only situations where tsk->cred may be accessed without an rcu read lock.
 */
static int audit_filter_rules(struct task_struct *tsk,
                              struct audit_krule *rule,
                              struct audit_context *ctx,
                              struct audit_names *name,
                              enum audit_state *state,
                              bool task_creation)
{
        const struct cred *cred;
        int i, need_sid = 1;
        u32 sid;

        cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);

        for (i = 0; i < rule->field_count; i++) {
                struct audit_field *f = &rule->fields[i];
                struct audit_names *n;
                int result = 0;
                pid_t pid;

                switch (f->type) {
                case AUDIT_PID:
                        pid = task_pid_nr(tsk);
                        result = audit_comparator(pid, f->op, f->val);
                        break;
                case AUDIT_PPID:
                        if (ctx) {
                                if (!ctx->ppid)
                                        ctx->ppid = task_ppid_nr(tsk);
                                result = audit_comparator(ctx->ppid, f->op, f->val);
                        }
                        break;
                case AUDIT_EXE:
                        result = audit_exe_compare(tsk, rule->exe);
                        break;
                case AUDIT_UID:
                        result = audit_uid_comparator(cred->uid, f->op, f->uid);
                        break;
                case AUDIT_EUID:
                        result = audit_uid_comparator(cred->euid, f->op, f->uid);
                        break;
                case AUDIT_SUID:
                        result = audit_uid_comparator(cred->suid, f->op, f->uid);
                        break;
                case AUDIT_FSUID:
                        result = audit_uid_comparator(cred->fsuid, f->op, f->uid);
                        break;
                case AUDIT_GID:
                        result = audit_gid_comparator(cred->gid, f->op, f->gid);
                        if (f->op == Audit_equal) {
                                if (!result)
                                        result = in_group_p(f->gid);
                        } else if (f->op == Audit_not_equal) {
                                if (result)
                                        result = !in_group_p(f->gid);
                        }
                        break;
                case AUDIT_EGID:
                        result = audit_gid_comparator(cred->egid, f->op, f->gid);
                        if (f->op == Audit_equal) {
                                if (!result)
                                        result = in_egroup_p(f->gid);
                        } else if (f->op == Audit_not_equal) {
                                if (result)
                                        result = !in_egroup_p(f->gid);
                        }
                        break;
                case AUDIT_SGID:
                        result = audit_gid_comparator(cred->sgid, f->op, f->gid);
                        break;
                case AUDIT_FSGID:
                        result = audit_gid_comparator(cred->fsgid, f->op, f->gid);
                        break;
                case AUDIT_PERS:
                        result = audit_comparator(tsk->personality, f->op, f->val);
                        break;
                case AUDIT_ARCH:
                        if (ctx)
                                result = audit_comparator(ctx->arch, f->op, f->val);
                        break;

                case AUDIT_EXIT:
                        if (ctx && ctx->return_valid)
                                result = audit_comparator(ctx->return_code, f->op, f->val);
                        break;
                case AUDIT_SUCCESS:
                        if (ctx && ctx->return_valid) {
                                if (f->val)
                                        result = audit_comparator(ctx->return_valid, f->op, AUDITSC_SUCCESS);
                                else
                                        result = audit_comparator(ctx->return_valid, f->op, AUDITSC_FAILURE);
                        }
                        break;
                case AUDIT_DEVMAJOR:
                        if (name) {
                                if (audit_comparator(MAJOR(name->dev), f->op, f->val) ||
                                    audit_comparator(MAJOR(name->rdev), f->op, f->val))
                                        ++result;
                        } else if (ctx) {
                                list_for_each_entry(n, &ctx->names_list, list) {
                                        if (audit_comparator(MAJOR(n->dev), f->op, f->val) ||
                                            audit_comparator(MAJOR(n->rdev), f->op, f->val)) {
                                                ++result;
                                                break;
                                        }
                                }
                        }
                        break;
                case AUDIT_DEVMINOR:
                        if (name) {
                                if (audit_comparator(MINOR(name->dev), f->op, f->val) ||
                                    audit_comparator(MINOR(name->rdev), f->op, f->val))
                                        ++result;
                        } else if (ctx) {
                                list_for_each_entry(n, &ctx->names_list, list) {
                                        if (audit_comparator(MINOR(n->dev), f->op, f->val) ||
                                            audit_comparator(MINOR(n->rdev), f->op, f->val)) {
                                                ++result;
                                                break;
                                        }
                                }
                        }
                        break;
                case AUDIT_INODE:
                        if (name)
                                result = audit_comparator(name->ino, f->op, f->val);
                        else if (ctx) {
                                list_for_each_entry(n, &ctx->names_list, list) {
                                        if (audit_comparator(n->ino, f->op, f->val)) {
                                                ++result;
                                                break;
                                        }
                                }
                        }
                        break;
                case AUDIT_OBJ_UID:
                        if (name) {
                                result = audit_uid_comparator(name->uid, f->op, f->uid);
                        } else if (ctx) {
                                list_for_each_entry(n, &ctx->names_list, list) {
                                        if (audit_uid_comparator(n->uid, f->op, f->uid)) {
                                                ++result;
                                                break;
                                        }
                                }
                        }
                        break;
                case AUDIT_OBJ_GID:
                        if (name) {
                                result = audit_gid_comparator(name->gid, f->op, f->gid);
                        } else if (ctx) {
                                list_for_each_entry(n, &ctx->names_list, list) {
                                        if (audit_gid_comparator(n->gid, f->op, f->gid)) {
                                                ++result;
                                                break;
                                        }
                                }
                        }
                        break;
                case AUDIT_WATCH:
                        if (name)
                                result = audit_watch_compare(rule->watch, name->ino, name->dev);
                        break;
                case AUDIT_DIR:
                        if (ctx)
                                result = match_tree_refs(ctx, rule->tree);
                        break;
                case AUDIT_LOGINUID:
                        result = audit_uid_comparator(tsk->loginuid, f->op, f->uid);
                        break;
                case AUDIT_LOGINUID_SET:
                        result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
                        break;
                case AUDIT_SUBJ_USER:
                case AUDIT_SUBJ_ROLE:
                case AUDIT_SUBJ_TYPE:
                case AUDIT_SUBJ_SEN:
                case AUDIT_SUBJ_CLR:
                        /* NOTE: this may return negative values indicating
                           a temporary error.  We simply treat this as a
                           match for now to avoid losing information that
                           may be wanted.   An error message will also be
                           logged upon error */
                        if (f->lsm_rule) {
                                if (need_sid) {
                                        security_task_getsecid(tsk, &sid);
                                        need_sid = 0;
                                }
                                result = security_audit_rule_match(sid, f->type,
                                                                  f->op,
                                                                  f->lsm_rule,
                                                                  ctx);
                        }
                        break;
                case AUDIT_OBJ_USER:
                case AUDIT_OBJ_ROLE:
                case AUDIT_OBJ_TYPE:
                case AUDIT_OBJ_LEV_LOW:
                case AUDIT_OBJ_LEV_HIGH:
                        /* The above note for AUDIT_SUBJ_USER...AUDIT_SUBJ_CLR
                           also applies here */
                        if (f->lsm_rule) {
                                /* Find files that match */
                                if (name) {
                                        result = security_audit_rule_match(
                                                   name->osid, f->type, f->op,
                                                   f->lsm_rule, ctx);
                                } else if (ctx) {
                                        list_for_each_entry(n, &ctx->names_list, list) {
                                                if (security_audit_rule_match(n->osid, f->type,
                                                                              f->op, f->lsm_rule,
                                                                              ctx)) {
                                                        ++result;
                                                        break;
                                                }
                                        }
                                }
                                /* Find ipc objects that match */
                                if (!ctx || ctx->type != AUDIT_IPC)
                                        break;
                                if (security_audit_rule_match(ctx->ipc.osid,
                                                              f->type, f->op,
                                                              f->lsm_rule, ctx))
                                        ++result;
                        }
                        break;
                case AUDIT_ARG0:
                case AUDIT_ARG1:
                case AUDIT_ARG2:
                case AUDIT_ARG3:
                        if (ctx)
                                result = audit_comparator(ctx->argv[f->type-AUDIT_ARG0], f->op, f->val);
                        break;
                case AUDIT_FILTERKEY:
                        /* ignore this field for filtering */
                        result = 1;
                        break;
                case AUDIT_PERM:
                        result = audit_match_perm(ctx, f->val);
                        break;
                case AUDIT_FILETYPE:
                        result = audit_match_filetype(ctx, f->val);
                        break;
                case AUDIT_FIELD_COMPARE:
                        result = audit_field_compare(tsk, cred, f, ctx, name);
                        break;
                }
                if (!result)
                        return 0;
        }

        if (ctx) {
                if (rule->prio <= ctx->prio)
                        return 0;
                if (rule->filterkey) {
                        kfree(ctx->filterkey);
                        ctx->filterkey = kstrdup(rule->filterkey, GFP_ATOMIC);
                }
                ctx->prio = rule->prio;
        }
        switch (rule->action) {
        case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
        case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
        }
        return 1;
}

/* At process creation time, we can determine if system-call auditing is
 * completely disabled for this task.  Since we only have the task
 * structure at this point, we can only check uid and gid.
 */
static enum audit_state audit_filter_task(struct task_struct *tsk, char **key)
{
        struct audit_entry *e;
        enum audit_state   state;

        rcu_read_lock();
        list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TASK], list) {
                if (audit_filter_rules(tsk, &e->rule, NULL, NULL,
                                       &state, true)) {
                        if (state == AUDIT_RECORD_CONTEXT)
                                *key = kstrdup(e->rule.filterkey, GFP_ATOMIC);
                        rcu_read_unlock();
                        return state;
                }
        }
        rcu_read_unlock();
        return AUDIT_BUILD_CONTEXT;
}

static int audit_in_mask(const struct audit_krule *rule, unsigned long val)
{
        int word, bit;

        if (val > 0xffffffff)
                return false;

        word = AUDIT_WORD(val);
        if (word >= AUDIT_BITMASK_SIZE)
                return false;

        bit = AUDIT_BIT(val);

        return rule->mask[word] & bit;
}

/* At syscall entry and exit time, this filter is called if the
 * audit_state is not low enough that auditing cannot take place, but is
 * also not high enough that we already know we have to write an audit
 * record (i.e., the state is AUDIT_SETUP_CONTEXT or AUDIT_BUILD_CONTEXT).
 */
static enum audit_state audit_filter_syscall(struct task_struct *tsk,
                                             struct audit_context *ctx,
                                             struct list_head *list)
{
        struct audit_entry *e;
        enum audit_state state;

        if (audit_pid && tsk->tgid == audit_pid)
                return AUDIT_DISABLED;

        rcu_read_lock();
        if (!list_empty(list)) {
                list_for_each_entry_rcu(e, list, list) {
                        if (audit_in_mask(&e->rule, ctx->major) &&
                            audit_filter_rules(tsk, &e->rule, ctx, NULL,
                                               &state, false)) {
                                rcu_read_unlock();
                                ctx->current_state = state;
                                return state;
                        }
                }
        }
        rcu_read_unlock();
        return AUDIT_BUILD_CONTEXT;
}

/*
 * Given an audit_name check the inode hash table to see if they match.
 * Called holding the rcu read lock to protect the use of audit_inode_hash
 */
static int audit_filter_inode_name(struct task_struct *tsk,
                                   struct audit_names *n,
                                   struct audit_context *ctx) {
        int h = audit_hash_ino((u32)n->ino);
        struct list_head *list = &audit_inode_hash[h];
        struct audit_entry *e;
        enum audit_state state;

        if (list_empty(list))
                return 0;

        list_for_each_entry_rcu(e, list, list) {
                if (audit_in_mask(&e->rule, ctx->major) &&
                    audit_filter_rules(tsk, &e->rule, ctx, n, &state, false)) {
                        ctx->current_state = state;
                        return 1;
                }
        }

        return 0;
}

/* At syscall exit time, this filter is called if any audit_names have been
 * collected during syscall processing.  We only check rules in sublists at hash
 * buckets applicable to the inode numbers in audit_names.
 * Regarding audit_state, same rules apply as for audit_filter_syscall().
 */
void audit_filter_inodes(struct task_struct *tsk, struct audit_context *ctx)
{
        struct audit_names *n;

        if (audit_pid && tsk->tgid == audit_pid)
                return;

        rcu_read_lock();

        list_for_each_entry(n, &ctx->names_list, list) {
                if (audit_filter_inode_name(tsk, n, ctx))
                        break;
        }
        rcu_read_unlock();
}

/* Transfer the audit context pointer to the caller, clearing it in the tsk's struct */
static inline struct audit_context *audit_take_context(struct task_struct *tsk,
                                                      int return_valid,
                                                      long return_code)
{
        struct audit_context *context = tsk->audit_context;

        if (!context)
                return NULL;
        context->return_valid = return_valid;

        /*
         * we need to fix up the return code in the audit logs if the actual
         * return codes are later going to be fixed up by the arch specific
         * signal handlers
         *
         * This is actually a test for:
         * (rc == ERESTARTSYS ) || (rc == ERESTARTNOINTR) ||
         * (rc == ERESTARTNOHAND) || (rc == ERESTART_RESTARTBLOCK)
         *
         * but is faster than a bunch of ||
         */
        if (unlikely(return_code <= -ERESTARTSYS) &&
            (return_code >= -ERESTART_RESTARTBLOCK) &&
            (return_code != -ENOIOCTLCMD))
                context->return_code = -EINTR;
        else
                context->return_code  = return_code;

        if (context->in_syscall && !context->dummy) {
                audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_EXIT]);
                audit_filter_inodes(tsk, context);
        }

        tsk->audit_context = NULL;
        return context;
}

static inline void audit_proctitle_free(struct audit_context *context)
{
        kfree(context->proctitle.value);
        context->proctitle.value = NULL;
        context->proctitle.len = 0;
}

static inline void audit_free_names(struct audit_context *context)
{
        struct audit_names *n, *next;

        list_for_each_entry_safe(n, next, &context->names_list, list) {
                list_del(&n->list);
                if (n->name)
                        putname(n->name);
                if (n->should_free)
                        kfree(n);
        }
        context->name_count = 0;
        path_put(&context->pwd);
        context->pwd.dentry = NULL;
        context->pwd.mnt = NULL;
}

static inline void audit_free_aux(struct audit_context *context)
{
        struct audit_aux_data *aux;

        while ((aux = context->aux)) {
                context->aux = aux->next;
                kfree(aux);
        }
        while ((aux = context->aux_pids)) {
                context->aux_pids = aux->next;
                kfree(aux);
        }
}

static inline struct audit_context *audit_alloc_context(enum audit_state state)
{
        struct audit_context *context;

        context = kzalloc(sizeof(*context), GFP_KERNEL);
        if (!context)
                return NULL;
        context->state = state;
        context->prio = state == AUDIT_RECORD_CONTEXT ? ~0ULL : 0;
        INIT_LIST_HEAD(&context->killed_trees);
        INIT_LIST_HEAD(&context->names_list);
        return context;
}

/**
 * audit_alloc - allocate an audit context block for a task
 * @tsk: task
 *
 * Filter on the task information and allocate a per-task audit context
 * if necessary.  Doing so turns on system call auditing for the
 * specified task.  This is called from copy_process, so no lock is
 * needed.
 */
int audit_alloc(struct task_struct *tsk)
{
        struct audit_context *context;
        enum audit_state     state;
        char *key = NULL;

        if (likely(!audit_ever_enabled))
                return 0; /* Return if not auditing. */

        state = audit_filter_task(tsk, &key);
        if (state == AUDIT_DISABLED) {
                clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
                return 0;
        }

        if (!(context = audit_alloc_context(state))) {
                kfree(key);
                audit_log_lost("out of memory in audit_alloc");
                return -ENOMEM;
        }
        context->filterkey = key;

        tsk->audit_context  = context;
        set_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
        return 0;
}

static inline void audit_free_context(struct audit_context *context)
{
        audit_free_names(context);
        unroll_tree_refs(context, NULL, 0);
        free_tree_refs(context);
        audit_free_aux(context);
        kfree(context->filterkey);
        kfree(context->sockaddr);
        audit_proctitle_free(context);
        kfree(context);
}

static int audit_log_pid_context(struct audit_context *context, pid_t pid,
                                 kuid_t auid, kuid_t uid, unsigned int sessionid,
                                 u32 sid, char *comm)
{
        struct audit_buffer *ab;
        char *ctx = NULL;
        u32 len;
        int rc = 0;

        ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
        if (!ab)
                return rc;

        audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
                         from_kuid(&init_user_ns, auid),
                         from_kuid(&init_user_ns, uid), sessionid);
        if (sid) {
                if (security_secid_to_secctx(sid, &ctx, &len)) {
                        audit_log_format(ab, " obj=(none)");
                        rc = 1;
                } else {
                        audit_log_format(ab, " obj=%s", ctx);
                        security_release_secctx(ctx, len);
                }
        }
        audit_log_format(ab, " ocomm=");
        audit_log_untrustedstring(ab, comm);
        audit_log_end(ab);

        return rc;
}

/*
 * to_send and len_sent accounting are very loose estimates.  We aren't
 * really worried about a hard cap to MAX_EXECVE_AUDIT_LEN so much as being
 * within about 500 bytes (next page boundary)
 *
 * why snprintf?  an int is up to 12 digits long.  if we just assumed when
 * logging that a[%d]= was going to be 16 characters long we would be wasting
 * space in every audit message.  In one 7500 byte message we can log up to
 * about 1000 min size arguments.  That comes down to about 50% waste of space
 * if we didn't do the snprintf to find out how long arg_num_len was.

 */
static int audit_log_single_execve_arg(struct audit_context *context,
                                        struct audit_buffer **ab,
                                        int arg_num,
                                        size_t *len_sent,
                                        const char __user *p,
                                        char *buf)
{
        char arg_num_len_buf[12];
        const char __user *tmp_p = p;
        /* how many digits are in arg_num? 5 is the length of ' a=""' */
        size_t arg_num_len = snprintf(arg_num_len_buf, 12, "%d", arg_num) + 5;
        size_t len, len_left, to_send;
        size_t max_execve_audit_len = MAX_EXECVE_AUDIT_LEN;
        unsigned int i, has_cntl = 0, too_long = 0;
        int ret;

        /* strnlen_user includes the null we don't want to send */
        len_left = len = strnlen_user(p, MAX_ARG_STRLEN) - 1;

        /*
         * We just created this mm, if we can't find the strings
         * we just copied into it something is _very_ wrong. Similar
         * for strings that are too long, we should not have created
         * any.
         */
        if (WARN_ON_ONCE(len < 0 || len > MAX_ARG_STRLEN - 1)) {
                send_sig(SIGKILL, current, 0);
                return -1;
        }

        /* walk the whole argument looking for non-ascii chars */
        do {
                if (len_left > MAX_EXECVE_AUDIT_LEN)
                        to_send = MAX_EXECVE_AUDIT_LEN;
                else
                        to_send = len_left;
                ret = copy_from_user(buf, tmp_p, to_send);
                /*
                 * There is no reason for this copy to be short. We just
                 * copied them here, and the mm hasn't been exposed to user-
                 * space yet.
                 */
                if (ret) {
                        WARN_ON(1);
                        send_sig(SIGKILL, current, 0);
                        return -1;
                }
                buf[to_send] = '\0';
                has_cntl = audit_string_contains_control(buf, to_send);
                if (has_cntl) {
                        /*
                         * hex messages get logged as 2 bytes, so we can only
                         * send half as much in each message
                         */
                        max_execve_audit_len = MAX_EXECVE_AUDIT_LEN / 2;
                        break;
                }
                len_left -= to_send;
                tmp_p += to_send;
        } while (len_left > 0);

        len_left = len;

        if (len > max_execve_audit_len)
                too_long = 1;

        /* rewalk the argument actually logging the message */
        for (i = 0; len_left > 0; i++) {
                int room_left;

                if (len_left > max_execve_audit_len)
                        to_send = max_execve_audit_len;
                else
                        to_send = len_left;

                /* do we have space left to send this argument in this ab? */
                room_left = MAX_EXECVE_AUDIT_LEN - arg_num_len - *len_sent;
                if (has_cntl)
                        room_left -= (to_send * 2);
                else
                        room_left -= to_send;
                if (room_left < 0) {
                        *len_sent = 0;
                        audit_log_end(*ab);
                        *ab = audit_log_start(context, GFP_KERNEL, AUDIT_EXECVE);
                        if (!*ab)
                                return 0;
                }

                /*
                 * first record needs to say how long the original string was
                 * so we can be sure nothing was lost.
                 */
                if ((i == 0) && (too_long))
                        audit_log_format(*ab, " a%d_len=%zu", arg_num,
                                         has_cntl ? 2*len : len);

                /*
                 * normally arguments are small enough to fit and we already
                 * filled buf above when we checked for control characters
                 * so don't bother with another copy_from_user
                 */
                if (len >= max_execve_audit_len)
                        ret = copy_from_user(buf, p, to_send);
                else
                        ret = 0;
                if (ret) {
                        WARN_ON(1);
                        send_sig(SIGKILL, current, 0);
                        return -1;
                }
                buf[to_send] = '\0';

                /* actually log it */
                audit_log_format(*ab, " a%d", arg_num);
                if (too_long)
                        audit_log_format(*ab, "[%d]", i);
                audit_log_format(*ab, "=");
                if (has_cntl)
                        audit_log_n_hex(*ab, buf, to_send);
                else
                        audit_log_string(*ab, buf);

                p += to_send;
                len_left -= to_send;
                *len_sent += arg_num_len;
                if (has_cntl)
                        *len_sent += to_send * 2;
                else
                        *len_sent += to_send;
        }
        /* include the null we didn't log */
        return len + 1;
}

static void audit_log_execve_info(struct audit_context *context,
                                  struct audit_buffer **ab)
{
        int i, len;
        size_t len_sent = 0;
        const char __user *p;
        char *buf;

        p = (const char __user *)current->mm->arg_start;

        audit_log_format(*ab, "argc=%d", context->execve.argc);

        /*
         * we need some kernel buffer to hold the userspace args.  Just
         * allocate one big one rather than allocating one of the right size
         * for every single argument inside audit_log_single_execve_arg()
         * should be <8k allocation so should be pretty safe.
         */
        buf = kmalloc(MAX_EXECVE_AUDIT_LEN + 1, GFP_KERNEL);
        if (!buf) {
                audit_panic("out of memory for argv string");
                return;
        }

        for (i = 0; i < context->execve.argc; i++) {
                len = audit_log_single_execve_arg(context, ab, i,
                                                  &len_sent, p, buf);
                if (len <= 0)
                        break;
                p += len;
        }
        kfree(buf);
}

static void show_special(struct audit_context *context, int *call_panic)
{
        struct audit_buffer *ab;
        int i;

        ab = audit_log_start(context, GFP_KERNEL, context->type);
        if (!ab)
                return;

        switch (context->type) {
        case AUDIT_SOCKETCALL: {
                int nargs = context->socketcall.nargs;
                audit_log_format(ab, "nargs=%d", nargs);
                for (i = 0; i < nargs; i++)
                        audit_log_format(ab, " a%d=%lx", i,
                                context->socketcall.args[i]);
                break; }
        case AUDIT_IPC: {
                u32 osid = context->ipc.osid;

                audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
                                 from_kuid(&init_user_ns, context->ipc.uid),
                                 from_kgid(&init_user_ns, context->ipc.gid),
                                 context->ipc.mode);
                if (osid) {
                        char *ctx = NULL;
                        u32 len;
                        if (security_secid_to_secctx(osid, &ctx, &len)) {
                                audit_log_format(ab, " osid=%u", osid);
                                *call_panic = 1;
                        } else {
                                audit_log_format(ab, " obj=%s", ctx);
                                security_release_secctx(ctx, len);
                        }
                }
                if (context->ipc.has_perm) {
                        audit_log_end(ab);
                        ab = audit_log_start(context, GFP_KERNEL,
                                             AUDIT_IPC_SET_PERM);
                        if (unlikely(!ab))
                                return;
                        audit_log_format(ab,
                                "qbytes=%lx ouid=%u ogid=%u mode=%#ho",
                                context->ipc.qbytes,
                                context->ipc.perm_uid,
                                context->ipc.perm_gid,
                                context->ipc.perm_mode);
                }
                break; }
        case AUDIT_MQ_OPEN: {
                audit_log_format(ab,
                        "oflag=0x%x mode=%#ho mq_flags=0x%lx mq_maxmsg=%ld "
                        "mq_msgsize=%ld mq_curmsgs=%ld",
                        context->mq_open.oflag, context->mq_open.mode,
                        context->mq_open.attr.mq_flags,
                        context->mq_open.attr.mq_maxmsg,
                        context->mq_open.attr.mq_msgsize,
                        context->mq_open.attr.mq_curmsgs);
                break; }
        case AUDIT_MQ_SENDRECV: {
                audit_log_format(ab,
                        "mqdes=%d msg_len=%zd msg_prio=%u "
                        "abs_timeout_sec=%ld abs_timeout_nsec=%ld",
                        context->mq_sendrecv.mqdes,
                        context->mq_sendrecv.msg_len,
                        context->mq_sendrecv.msg_prio,
                        context->mq_sendrecv.abs_timeout.tv_sec,
                        context->mq_sendrecv.abs_timeout.tv_nsec);
                break; }
        case AUDIT_MQ_NOTIFY: {
                audit_log_format(ab, "mqdes=%d sigev_signo=%d",
                                context->mq_notify.mqdes,
                                context->mq_notify.sigev_signo);
                break; }
        case AUDIT_MQ_GETSETATTR: {
                struct mq_attr *attr = &context->mq_getsetattr.mqstat;
                audit_log_format(ab,
                        "mqdes=%d mq_flags=0x%lx mq_maxmsg=%ld mq_msgsize=%ld "
                        "mq_curmsgs=%ld ",
                        context->mq_getsetattr.mqdes,
                        attr->mq_flags, attr->mq_maxmsg,
                        attr->mq_msgsize, attr->mq_curmsgs);
                break; }
        case AUDIT_CAPSET: {
                audit_log_format(ab, "pid=%d", context->capset.pid);
                audit_log_cap(ab, "cap_pi", &context->capset.cap.inheritable);
                audit_log_cap(ab, "cap_pp", &context->capset.cap.permitted);
                audit_log_cap(ab, "cap_pe", &context->capset.cap.effective);
                break; }
        case AUDIT_MMAP: {
                audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
                                 context->mmap.flags);
                break; }
        case AUDIT_EXECVE: {
                audit_log_execve_info(context, &ab);
                break; }
        }
        audit_log_end(ab);
}

static inline int audit_proctitle_rtrim(char *proctitle, int len)
{
        char *end = proctitle + len - 1;
        while (end > proctitle && !isprint(*end))
                end--;

        /* catch the case where proctitle is only 1 non-print character */
        len = end - proctitle + 1;
        len -= isprint(proctitle[len-1]) == 0;
        return len;
}

static void audit_log_proctitle(struct task_struct *tsk,
                         struct audit_context *context)
{
        int res;
        char *buf;
        char *msg = "(null)";
        int len = strlen(msg);
        struct audit_buffer *ab;

        ab = audit_log_start(context, GFP_KERNEL, AUDIT_PROCTITLE);
        if (!ab)
                return; /* audit_panic or being filtered */

        audit_log_format(ab, "proctitle=");

        /* Not  cached */
        if (!context->proctitle.value) {
                buf = kmalloc(MAX_PROCTITLE_AUDIT_LEN, GFP_KERNEL);
                if (!buf)
                        goto out;
                /* Historically called this from procfs naming */
                res = get_cmdline(tsk, buf, MAX_PROCTITLE_AUDIT_LEN);
                if (res == 0) {
                        kfree(buf);
                        goto out;
                }
                res = audit_proctitle_rtrim(buf, res);
                if (res == 0) {
                        kfree(buf);
                        goto out;
                }
                context->proctitle.value = buf;
                context->proctitle.len = res;
        }
        msg = context->proctitle.value;
        len = context->proctitle.len;
out:
        audit_log_n_untrustedstring(ab, msg, len);
        audit_log_end(ab);
}

static void audit_log_exit(struct audit_context *context, struct task_struct *tsk)
{
        int i, call_panic = 0;
        struct audit_buffer *ab;
        struct audit_aux_data *aux;
        struct audit_names *n;

        /* tsk == current */
        context->personality = tsk->personality;

        ab = audit_log_start(context, GFP_KERNEL, AUDIT_SYSCALL);
        if (!ab)
                return;         /* audit_panic has been called */
        audit_log_format(ab, "arch=%x syscall=%d",
                         context->arch, context->major);
        if (context->personality != PER_LINUX)
                audit_log_format(ab, " per=%lx", context->personality);
        if (context->return_valid)
                audit_log_format(ab, " success=%s exit=%ld",
                                 (context->return_valid==AUDITSC_SUCCESS)?"yes":"no",
                                 context->return_code);

        audit_log_format(ab,
                         " a0=%lx a1=%lx a2=%lx a3=%lx items=%d",
                         context->argv[0],
                         context->argv[1],
                         context->argv[2],
                         context->argv[3],
                         context->name_count);

        audit_log_task_info(ab, tsk);
        audit_log_key(ab, context->filterkey);
        audit_log_end(ab);

        for (aux = context->aux; aux; aux = aux->next) {

                ab = audit_log_start(context, GFP_KERNEL, aux->type);
                if (!ab)
                        continue; /* audit_panic has been called */

                switch (aux->type) {

                case AUDIT_BPRM_FCAPS: {
                        struct audit_aux_data_bprm_fcaps *axs = (void *)aux;
                        audit_log_format(ab, "fver=%x", axs->fcap_ver);
                        audit_log_cap(ab, "fp", &axs->fcap.permitted);
                        audit_log_cap(ab, "fi", &axs->fcap.inheritable);
                        audit_log_format(ab, " fe=%d", axs->fcap.fE);
                        audit_log_cap(ab, "old_pp", &axs->old_pcap.permitted);
                        audit_log_cap(ab, "old_pi", &axs->old_pcap.inheritable);
                        audit_log_cap(ab, "old_pe", &axs->old_pcap.effective);
                        audit_log_cap(ab, "new_pp", &axs->new_pcap.permitted);
                        audit_log_cap(ab, "new_pi", &axs->new_pcap.inheritable);
                        audit_log_cap(ab, "new_pe", &axs->new_pcap.effective);
                        break; }

                }
                audit_log_end(ab);
        }

        if (context->type)
                show_special(context, &call_panic);

        if (context->fds[0] >= 0) {
                ab = audit_log_start(context, GFP_KERNEL, AUDIT_FD_PAIR);
                if (ab) {
                        audit_log_format(ab, "fd0=%d fd1=%d",
                                        context->fds[0], context->fds[1]);
                        audit_log_end(ab);
                }
        }

        if (context->sockaddr_len) {
                ab = audit_log_start(context, GFP_KERNEL, AUDIT_SOCKADDR);
                if (ab) {
                        audit_log_format(ab, "saddr=");
                        audit_log_n_hex(ab, (void *)context->sockaddr,
                                        context->sockaddr_len);
                        audit_log_end(ab);
                }
        }

        for (aux = context->aux_pids; aux; aux = aux->next) {
                struct audit_aux_data_pids *axs = (void *)aux;

                for (i = 0; i < axs->pid_count; i++)
                        if (audit_log_pid_context(context, axs->target_pid[i],
                                                  axs->target_auid[i],
                                                  axs->target_uid[i],
                                                  axs->target_sessionid[i],
                                                  axs->target_sid[i],
                                                  axs->target_comm[i]))
                                call_panic = 1;
        }

        if (context->target_pid &&
            audit_log_pid_context(context, context->target_pid,
                                  context->target_auid, context->target_uid,
                                  context->target_sessionid,
                                  context->target_sid, context->target_comm))
                        call_panic = 1;

        if (context->pwd.dentry && context->pwd.mnt) {
                ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD);
                if (ab) {
                        audit_log_d_path(ab, " cwd=", &context->pwd);
                        audit_log_end(ab);
                }
        }

        i = 0;
        list_for_each_entry(n, &context->names_list, list) {
                if (n->hidden)
                        continue;
                audit_log_name(context, n, NULL, i++, &call_panic);
        }

        audit_log_proctitle(tsk, context);

        /* Send end of event record to help user space know we are finished */
        ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
        if (ab)
                audit_log_end(ab);
        if (call_panic)
                audit_panic("error converting sid to string");
}

/**
 * audit_free - free a per-task audit context
 * @tsk: task whose audit context block to free
 *
 * Called from copy_process and do_exit
 */
void __audit_free(struct task_struct *tsk)
{
        struct audit_context *context;

        context = audit_take_context(tsk, 0, 0);
        if (!context)
                return;

        /* Check for system calls that do not go through the exit
         * function (e.g., exit_group), then free context block.
         * We use GFP_ATOMIC here because we might be doing this
         * in the context of the idle thread */
        /* that can happen only if we are called from do_exit() */
        if (context->in_syscall && context->current_state == AUDIT_RECORD_CONTEXT)
                audit_log_exit(context, tsk);
        if (!list_empty(&context->killed_trees))
                audit_kill_trees(&context->killed_trees);

        audit_free_context(context);
}

/**
 * audit_syscall_entry - fill in an audit record at syscall entry
 * @major: major syscall type (function)
 * @a1: additional syscall register 1
 * @a2: additional syscall register 2
 * @a3: additional syscall register 3
 * @a4: additional syscall register 4
 *
 * Fill in audit context at syscall entry.  This only happens if the
 * audit context was created when the task was created and the state or
 * filters demand the audit context be built.  If the state from the
 * per-task filter or from the per-syscall filter is AUDIT_RECORD_CONTEXT,
 * then the record will be written at syscall exit time (otherwise, it
 * will only be written if another part of the kernel requests that it
 * be written).
 */
void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2,
                           unsigned long a3, unsigned long a4)
{
        struct task_struct *tsk = current;
        struct audit_context *context = tsk->audit_context;
        enum audit_state     state;

        if (!context)
                return;

        BUG_ON(context->in_syscall || context->name_count);

        if (!audit_enabled)
                return;

        context->arch       = syscall_get_arch();
        context->major      = major;
        context->argv[0]    = a1;
        context->argv[1]    = a2;
        context->argv[2]    = a3;
        context->argv[3]    = a4;

        state = context->state;
        context->dummy = !audit_n_rules;
        if (!context->dummy && state == AUDIT_BUILD_CONTEXT) {
                context->prio = 0;
                state = audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_ENTRY]);
        }
        if (state == AUDIT_DISABLED)
                return;

        context->serial     = 0;
        context->ctime      = CURRENT_TIME;
        context->in_syscall = 1;
        context->current_state  = state;
        context->ppid       = 0;
}

/**
 * audit_syscall_exit - deallocate audit context after a system call
 * @success: success value of the syscall
 * @return_code: return value of the syscall
 *
 * Tear down after system call.  If the audit context has been marked as
 * auditable (either because of the AUDIT_RECORD_CONTEXT state from
 * filtering, or because some other part of the kernel wrote an audit
 * message), then write out the syscall information.  In call cases,
 * free the names stored from getname().
 */
void __audit_syscall_exit(int success, long return_code)
{
        struct task_struct *tsk = current;
        struct audit_context *context;

        if (success)
                success = AUDITSC_SUCCESS;
        else
                success = AUDITSC_FAILURE;

        context = audit_take_context(tsk, success, return_code);
        if (!context)
                return;

        if (context->in_syscall && context->current_state == AUDIT_RECORD_CONTEXT)
                audit_log_exit(context, tsk);

        context->in_syscall = 0;
        context->prio = context->state == AUDIT_RECORD_CONTEXT ? ~0ULL : 0;

        if (!list_empty(&context->killed_trees))
                audit_kill_trees(&context->killed_trees);

        audit_free_names(context);
        unroll_tree_refs(context, NULL, 0);
        audit_free_aux(context);
        context->aux = NULL;
        context->aux_pids = NULL;
        context->target_pid = 0;
        context->target_sid = 0;
        context->sockaddr_len = 0;
        context->type = 0;
        context->fds[0] = -1;
        if (context->state != AUDIT_RECORD_CONTEXT) {
                kfree(context->filterkey);
                context->filterkey = NULL;
        }
        tsk->audit_context = context;
}

static inline void handle_one(const struct inode *inode)
{
#ifdef CONFIG_AUDIT_TREE
        struct audit_context *context;
        struct audit_tree_refs *p;
        struct audit_chunk *chunk;
        int count;
        if (likely(hlist_empty(&inode->i_fsnotify_marks)))
                return;
        context = current->audit_context;
        p = context->trees;
        count = context->tree_count;
        rcu_read_lock();
        chunk = audit_tree_lookup(inode);
        rcu_read_unlock();
        if (!chunk)
                return;
        if (likely(put_tree_ref(context, chunk)))
                return;
        if (unlikely(!grow_tree_refs(context))) {
                pr_warn("out of memory, audit has lost a tree reference\n");
                audit_set_auditable(context);
                audit_put_chunk(chunk);
                unroll_tree_refs(context, p, count);
                return;
        }
        put_tree_ref(context, chunk);
#endif
}

static void handle_path(const struct dentry *dentry)
{
#ifdef CONFIG_AUDIT_TREE
        struct audit_context *context;
        struct audit_tree_refs *p;
        const struct dentry *d, *parent;
        struct audit_chunk *drop;
        unsigned long seq;
        int count;

        context = current->audit_context;
        p = context->trees;
        count = context->tree_count;
retry:
        drop = NULL;
        d = dentry;
        rcu_read_lock();
        seq = read_seqbegin(&rename_lock);
        for(;;) {
                struct inode *inode = d_backing_inode(d);
                if (inode && unlikely(!hlist_empty(&inode->i_fsnotify_marks))) {
                        struct audit_chunk *chunk;
                        chunk = audit_tree_lookup(inode);
                        if (chunk) {
                                if (unlikely(!put_tree_ref(context, chunk))) {
                                        drop = chunk;
                                        break;
                                }
                        }
                }
                parent = d->d_parent;
                if (parent == d)
                        break;
                d = parent;
        }
        if (unlikely(read_seqretry(&rename_lock, seq) || drop)) {  /* in this order */
                rcu_read_unlock();
                if (!drop) {
                        /* just a race with rename */
                        unroll_tree_refs(context, p, count);
                        goto retry;
                }
                audit_put_chunk(drop);
                if (grow_tree_refs(context)) {
                        /* OK, got more space */
                        unroll_tree_refs(context, p, count);
                        goto retry;
                }
                /* too bad */
                pr_warn("out of memory, audit has lost a tree reference\n");
                unroll_tree_refs(context, p, count);
                audit_set_auditable(context);
                return;
        }
        rcu_read_unlock();
#endif
}

static struct audit_names *audit_alloc_name(struct audit_context *context,
                                                unsigned char type)
{
        struct audit_names *aname;

        if (context->name_count < AUDIT_NAMES) {
                aname = &context->preallocated_names[context->name_count];
                memset(aname, 0, sizeof(*aname));
        } else {
                aname = kzalloc(sizeof(*aname), GFP_NOFS);
                if (!aname)
                        return NULL;
                aname->should_free = true;
        }

        aname->ino = AUDIT_INO_UNSET;
        aname->type = type;
        list_add_tail(&aname->list, &context->names_list);

        context->name_count++;
        return aname;
}

/**
 * audit_reusename - fill out filename with info from existing entry
 * @uptr: userland ptr to pathname
 *
 * Search the audit_names list for the current audit context. If there is an
 * existing entry with a matching "uptr" then return the filename
 * associated with that audit_name. If not, return NULL.
 */
struct filename *
__audit_reusename(const __user char *uptr)
{
        struct audit_context *context = current->audit_context;
        struct audit_names *n;

        list_for_each_entry(n, &context->names_list, list) {
                if (!n->name)
                        continue;
                if (n->name->uptr == uptr) {
                        n->name->refcnt++;
                        return n->name;
                }
        }
        return NULL;
}

/**
 * audit_getname - add a name to the list
 * @name: name to add
 *
 * Add a name to the list of audit names for this context.
 * Called from fs/namei.c:getname().
 */
void __audit_getname(struct filename *name)
{
        struct audit_context *context = current->audit_context;
        struct audit_names *n;

        if (!context->in_syscall)
                return;

        n = audit_alloc_name(context, AUDIT_TYPE_UNKNOWN);
        if (!n)
                return;

        n->name = name;
        n->name_len = AUDIT_NAME_FULL;
        name->aname = n;
        name->refcnt++;

        if (!context->pwd.dentry)
                get_fs_pwd(current->fs, &context->pwd);
}

/**
 * __audit_inode - store the inode and device from a lookup
 * @name: name being audited
 * @dentry: dentry being audited
 * @flags: attributes for this particular entry
 */
void __audit_inode(struct filename *name, const struct dentry *dentry,
                   unsigned int flags)
{
        struct audit_context *context = current->audit_context;
        struct inode *inode = d_backing_inode(dentry);
        struct audit_names *n;
        bool parent = flags & AUDIT_INODE_PARENT;

        if (!context->in_syscall)
                return;

        if (!name)
                goto out_alloc;

        /*
         * If we have a pointer to an audit_names entry already, then we can
         * just use it directly if the type is correct.
         */
        n = name->aname;
        if (n) {
                if (parent) {
                        if (n->type == AUDIT_TYPE_PARENT ||
                            n->type == AUDIT_TYPE_UNKNOWN)
                                goto out;
                } else {
                        if (n->type != AUDIT_TYPE_PARENT)
                                goto out;
                }
        }

        list_for_each_entry_reverse(n, &context->names_list, list) {
                if (n->ino) {
                        /* valid inode number, use that for the comparison */
                        if (n->ino != inode->i_ino ||
                            n->dev != inode->i_sb->s_dev)
                                continue;
                } else if (n->name) {
                        /* inode number has not been set, check the name */
                        if (strcmp(n->name->name, name->name))
                                continue;
                } else
                        /* no inode and no name (?!) ... this is odd ... */
                        continue;

                /* match the correct record type */
                if (parent) {
                        if (n->type == AUDIT_TYPE_PARENT ||
                            n->type == AUDIT_TYPE_UNKNOWN)
                                goto out;
                } else {
                        if (n->type != AUDIT_TYPE_PARENT)
                                goto out;
                }
        }

out_alloc:
        /* unable to find an entry with both a matching name and type */
        n = audit_alloc_name(context, AUDIT_TYPE_UNKNOWN);
        if (!n)
                return;
        if (name) {
                n->name = name;
                name->refcnt++;
        }

out:
        if (parent) {
                n->name_len = n->name ? parent_len(n->name->name) : AUDIT_NAME_FULL;
                n->type = AUDIT_TYPE_PARENT;
                if (flags & AUDIT_INODE_HIDDEN)
                        n->hidden = true;
        } else {
                n->name_len = AUDIT_NAME_FULL;
                n->type = AUDIT_TYPE_NORMAL;
        }
        handle_path(dentry);
        audit_copy_inode(n, dentry, inode);
}

void __audit_file(const struct file *file)
{
        __audit_inode(NULL, file->f_path.dentry, 0);
}

/**
 * __audit_inode_child - collect inode info for created/removed objects
 * @parent: inode of dentry parent
 * @dentry: dentry being audited
 * @type:   AUDIT_TYPE_* value that we're looking for
 *
 * For syscalls that create or remove filesystem objects, audit_inode
 * can only collect information for the filesystem object's parent.
 * This call updates the audit context with the child's information.
 * Syscalls that create a new filesystem object must be hooked after
 * the object is created.  Syscalls that remove a filesystem object
 * must be hooked prior, in order to capture the target inode during
 * unsuccessful attempts.
 */
void __audit_inode_child(struct inode *parent,
                         const struct dentry *dentry,
                         const unsigned char type)
{
        struct audit_context *context = current->audit_context;
        struct inode *inode = d_backing_inode(dentry);
        const char *dname = dentry->d_name.name;
        struct audit_names *n, *found_parent = NULL, *found_child = NULL;

        if (!context->in_syscall)
                return;

        if (inode)
                handle_one(inode);

        /* look for a parent entry first */
        list_for_each_entry(n, &context->names_list, list) {
                if (!n->name ||
                    (n->type != AUDIT_TYPE_PARENT &&
                     n->type != AUDIT_TYPE_UNKNOWN))
                        continue;

                if (n->ino == parent->i_ino && n->dev == parent->i_sb->s_dev &&
                    !audit_compare_dname_path(dname,
                                              n->name->name, n->name_len)) {
                        if (n->type == AUDIT_TYPE_UNKNOWN)
                                n->type = AUDIT_TYPE_PARENT;
                        found_parent = n;
                        break;
                }
        }

        /* is there a matching child entry? */
        list_for_each_entry(n, &context->names_list, list) {
                /* can only match entries that have a name */
                if (!n->name ||
                    (n->type != type && n->type != AUDIT_TYPE_UNKNOWN))
                        continue;

                if (!strcmp(dname, n->name->name) ||
                    !audit_compare_dname_path(dname, n->name->name,
                                                found_parent ?
                                                found_parent->name_len :
                                                AUDIT_NAME_FULL)) {
                        if (n->type == AUDIT_TYPE_UNKNOWN)
                                n->type = type;
                        found_child = n;
                        break;
                }
        }

        if (!found_parent) {
                /* create a new, "anonymous" parent record */
                n = audit_alloc_name(context, AUDIT_TYPE_PARENT);
                if (!n)
                        return;
                audit_copy_inode(n, NULL, parent);
        }

        if (!found_child) {
                found_child = audit_alloc_name(context, type);
                if (!found_child)
                        return;

                /* Re-use the name belonging to the slot for a matching parent
                 * directory. All names for this context are relinquished in
                 * audit_free_names() */
                if (found_parent) {
                        found_child->name = found_parent->name;
                        found_child->name_len = AUDIT_NAME_FULL;
                        found_child->name->refcnt++;
                }
        }

        if (inode)
                audit_copy_inode(found_child, dentry, inode);
        else
                found_child->ino = AUDIT_INO_UNSET;
}
EXPORT_SYMBOL_GPL(__audit_inode_child);

/**
 * auditsc_get_stamp - get local copies of audit_context values
 * @ctx: audit_context for the task
 * @t: timespec to store time recorded in the audit_context
 * @serial: serial value that is recorded in the audit_context
 *
 * Also sets the context as auditable.
 */
int auditsc_get_stamp(struct audit_context *ctx,
                       struct timespec *t, unsigned int *serial)
{
        if (!ctx->in_syscall)
                return 0;
        if (!ctx->serial)
                ctx->serial = audit_serial();
        t->tv_sec  = ctx->ctime.tv_sec;
        t->tv_nsec = ctx->ctime.tv_nsec;
        *serial    = ctx->serial;
        if (!ctx->prio) {
                ctx->prio = 1;
                ctx->current_state = AUDIT_RECORD_CONTEXT;
        }
        return 1;
}

/* global counter which is incremented every time something logs in */
static atomic_t session_id = ATOMIC_INIT(0);

static int audit_set_loginuid_perm(kuid_t loginuid)
{
        /* if we are unset, we don't need privs */
        if (!audit_loginuid_set(current))
                return 0;
        /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
        if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
                return -EPERM;
        /* it is set, you need permission */
        if (!capable(CAP_AUDIT_CONTROL))
                return -EPERM;
        /* reject if this is not an unset and we don't allow that */
        if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID) && uid_valid(loginuid))
                return -EPERM;
        return 0;
}

static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
                                   unsigned int oldsessionid, unsigned int sessionid,
                                   int rc)
{
        struct audit_buffer *ab;
        uid_t uid, oldloginuid, loginuid;

        if (!audit_enabled)
                return;

        uid = from_kuid(&init_user_ns, task_uid(current));
        oldloginuid = from_kuid(&init_user_ns, koldloginuid);
        loginuid = from_kuid(&init_user_ns, kloginuid),

        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
        if (!ab)
                return;
        audit_log_format(ab, "pid=%d uid=%u", task_pid_nr(current), uid);
        audit_log_task_context(ab);
        audit_log_format(ab, " old-auid=%u auid=%u old-ses=%u ses=%u res=%d",
                         oldloginuid, loginuid, oldsessionid, sessionid, !rc);
        audit_log_end(ab);
}

/**
 * audit_set_loginuid - set current task's audit_context loginuid
 * @loginuid: loginuid value
 *
 * Returns 0.
 *
 * Called (set) from fs/proc/base.c::proc_loginuid_write().
 */
int audit_set_loginuid(kuid_t loginuid)
{
        struct task_struct *task = current;
        unsigned int oldsessionid, sessionid = (unsigned int)-1;
        kuid_t oldloginuid;
        int rc;

        oldloginuid = audit_get_loginuid(current);
        oldsessionid = audit_get_sessionid(current);

        rc = audit_set_loginuid_perm(loginuid);
        if (rc)
                goto out;

        /* are we setting or clearing? */
        if (uid_valid(loginuid))
                sessionid = (unsigned int)atomic_inc_return(&session_id);

        task->sessionid = sessionid;
        task->loginuid = loginuid;
out:
        audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
        return rc;
}

/**
 * __audit_mq_open - record audit data for a POSIX MQ open
 * @oflag: open flag
 * @mode: mode bits
 * @attr: queue attributes
 *
 */
void __audit_mq_open(int oflag, umode_t mode, struct mq_attr *attr)
{
        struct audit_context *context = current->audit_context;

        if (attr)
                memcpy(&context->mq_open.attr, attr, sizeof(struct mq_attr));
        else
                memset(&context->mq_open.attr, 0, sizeof(struct mq_attr));

        context->mq_open.oflag = oflag;
        context->mq_open.mode = mode;

        context->type = AUDIT_MQ_OPEN;
}

/**
 * __audit_mq_sendrecv - record audit data for a POSIX MQ timed send/receive
 * @mqdes: MQ descriptor
 * @msg_len: Message length
 * @msg_prio: Message priority
 * @abs_timeout: Message timeout in absolute time
 *
 */
void __audit_mq_sendrecv(mqd_t mqdes, size_t msg_len, unsigned int msg_prio,
                        const struct timespec *abs_timeout)
{
        struct audit_context *context = current->audit_context;
        struct timespec *p = &context->mq_sendrecv.abs_timeout;

        if (abs_timeout)
                memcpy(p, abs_timeout, sizeof(struct timespec));
        else
                memset(p, 0, sizeof(struct timespec));

        context->mq_sendrecv.mqdes = mqdes;
        context->mq_sendrecv.msg_len = msg_len;
        context->mq_sendrecv.msg_prio = msg_prio;

        context->type = AUDIT_MQ_SENDRECV;
}

/**
 * __audit_mq_notify - record audit data for a POSIX MQ notify
 * @mqdes: MQ descriptor
 * @notification: Notification event
 *
 */

void __audit_mq_notify(mqd_t mqdes, const struct sigevent *notification)
{
        struct audit_context *context = current->audit_context;

        if (notification)
                context->mq_notify.sigev_signo = notification->sigev_signo;
        else
                context->mq_notify.sigev_signo = 0;

        context->mq_notify.mqdes = mqdes;
        context->type = AUDIT_MQ_NOTIFY;
}

/**
 * __audit_mq_getsetattr - record audit data for a POSIX MQ get/set attribute
 * @mqdes: MQ descriptor
 * @mqstat: MQ flags
 *
 */
void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
{
        struct audit_context *context = current->audit_context;
        context->mq_getsetattr.mqdes = mqdes;
        context->mq_getsetattr.mqstat = *mqstat;
        context->type = AUDIT_MQ_GETSETATTR;
}

/**
 * audit_ipc_obj - record audit data for ipc object
 * @ipcp: ipc permissions
 *
 */
void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
{
        struct audit_context *context = current->audit_context;
        context->ipc.uid = ipcp->uid;
        context->ipc.gid = ipcp->gid;
        context->ipc.mode = ipcp->mode;
        context->ipc.has_perm = 0;
        security_ipc_getsecid(ipcp, &context->ipc.osid);
        context->type = AUDIT_IPC;
}

/**
 * audit_ipc_set_perm - record audit data for new ipc permissions
 * @qbytes: msgq bytes
 * @uid: msgq user id
 * @gid: msgq group id
 * @mode: msgq mode (permissions)
 *
 * Called only after audit_ipc_obj().
 */
void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode)
{
        struct audit_context *context = current->audit_context;

        context->ipc.qbytes = qbytes;
        context->ipc.perm_uid = uid;
        context->ipc.perm_gid = gid;
        context->ipc.perm_mode = mode;
        context->ipc.has_perm = 1;
}

void __audit_bprm(struct linux_binprm *bprm)
{
        struct audit_context *context = current->audit_context;

        context->type = AUDIT_EXECVE;
        context->execve.argc = bprm->argc;
}


/**
 * audit_socketcall - record audit data for sys_socketcall
 * @nargs: number of args, which should not be more than AUDITSC_ARGS.
 * @args: args array
 *
 */
int __audit_socketcall(int nargs, unsigned long *args)
{
        struct audit_context *context = current->audit_context;

        if (nargs <= 0 || nargs > AUDITSC_ARGS || !args)
                return -EINVAL;
        context->type = AUDIT_SOCKETCALL;
        context->socketcall.nargs = nargs;
        memcpy(context->socketcall.args, args, nargs * sizeof(unsigned long));
        return 0;
}

/**
 * __audit_fd_pair - record audit data for pipe and socketpair
 * @fd1: the first file descriptor
 * @fd2: the second file descriptor
 *
 */
void __audit_fd_pair(int fd1, int fd2)
{
        struct audit_context *context = current->audit_context;
        context->fds[0] = fd1;
        context->fds[1] = fd2;
}

/**
 * audit_sockaddr - record audit data for sys_bind, sys_connect, sys_sendto
 * @len: data length in user space
 * @a: data address in kernel space
 *
 * Returns 0 for success or NULL context or < 0 on error.
 */
int __audit_sockaddr(int len, void *a)
{
        struct audit_context *context = current->audit_context;

        if (!context->sockaddr) {
                void *p = kmalloc(sizeof(struct sockaddr_storage), GFP_KERNEL);
                if (!p)
                        return -ENOMEM;
                context->sockaddr = p;
        }

        context->sockaddr_len = len;
        memcpy(context->sockaddr, a, len);
        return 0;
}

void __audit_ptrace(struct task_struct *t)
{
        struct audit_context *context = current->audit_context;

        context->target_pid = task_pid_nr(t);
        context->target_auid = audit_get_loginuid(t);
        context->target_uid = task_uid(t);
        context->target_sessionid = audit_get_sessionid(t);
        security_task_getsecid(t, &context->target_sid);
        memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
}

/**
 * audit_signal_info - record signal info for shutting down audit subsystem
 * @sig: signal value
 * @t: task being signaled
 *
 * If the audit subsystem is being terminated, record the task (pid)
 * and uid that is doing that.
 */
int __audit_signal_info(int sig, struct task_struct *t)
{
        struct audit_aux_data_pids *axp;
        struct task_struct *tsk = current;
        struct audit_context *ctx = tsk->audit_context;
        kuid_t uid = current_uid(), t_uid = task_uid(t);

        if (audit_pid && t->tgid == audit_pid) {
                if (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1 || sig == SIGUSR2) {
                        audit_sig_pid = task_pid_nr(tsk);
                        if (uid_valid(tsk->loginuid))
                                audit_sig_uid = tsk->loginuid;
                        else
                                audit_sig_uid = uid;
                        security_task_getsecid(tsk, &audit_sig_sid);
                }
                if (!audit_signals || audit_dummy_context())
                        return 0;
        }

        /* optimize the common case by putting first signal recipient directly
         * in audit_context */
        if (!ctx->target_pid) {
                ctx->target_pid = task_tgid_nr(t);
                ctx->target_auid = audit_get_loginuid(t);
                ctx->target_uid = t_uid;
                ctx->target_sessionid = audit_get_sessionid(t);
                security_task_getsecid(t, &ctx->target_sid);
                memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
                return 0;
        }

        axp = (void *)ctx->aux_pids;
        if (!axp || axp->pid_count == AUDIT_AUX_PIDS) {
                axp = kzalloc(sizeof(*axp), GFP_ATOMIC);
                if (!axp)
                        return -ENOMEM;

                axp->d.type = AUDIT_OBJ_PID;
                axp->d.next = ctx->aux_pids;
                ctx->aux_pids = (void *)axp;
        }
        BUG_ON(axp->pid_count >= AUDIT_AUX_PIDS);

        axp->target_pid[axp->pid_count] = task_tgid_nr(t);
        axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
        axp->target_uid[axp->pid_count] = t_uid;
        axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
        security_task_getsecid(t, &axp->target_sid[axp->pid_count]);
        memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
        axp->pid_count++;

        return 0;
}

/**
 * __audit_log_bprm_fcaps - store information about a loading bprm and relevant fcaps
 * @bprm: pointer to the bprm being processed
 * @new: the proposed new credentials
 * @old: the old credentials
 *
 * Simply check if the proc already has the caps given by the file and if not
 * store the priv escalation info for later auditing at the end of the syscall
 *
 * -Eric
 */
int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
                           const struct cred *new, const struct cred *old)
{
        struct audit_aux_data_bprm_fcaps *ax;
        struct audit_context *context = current->audit_context;
        struct cpu_vfs_cap_data vcaps;

        ax = kmalloc(sizeof(*ax), GFP_KERNEL);
        if (!ax)
                return -ENOMEM;

        ax->d.type = AUDIT_BPRM_FCAPS;
        ax->d.next = context->aux;
        context->aux = (void *)ax;

        get_vfs_caps_from_disk(bprm->file->f_path.dentry, &vcaps);

        ax->fcap.permitted = vcaps.permitted;
        ax->fcap.inheritable = vcaps.inheritable;
        ax->fcap.fE = !!(vcaps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
        ax->fcap_ver = (vcaps.magic_etc & VFS_CAP_REVISION_MASK) >> VFS_CAP_REVISION_SHIFT;

        ax->old_pcap.permitted   = old->cap_permitted;
        ax->old_pcap.inheritable = old->cap_inheritable;
        ax->old_pcap.effective   = old->cap_effective;

        ax->new_pcap.permitted   = new->cap_permitted;
        ax->new_pcap.inheritable = new->cap_inheritable;
        ax->new_pcap.effective   = new->cap_effective;
        return 0;
}

/**
 * __audit_log_capset - store information about the arguments to the capset syscall
 * @new: the new credentials
 * @old: the old (current) credentials
 *
 * Record the arguments userspace sent to sys_capset for later printing by the
 * audit system if applicable
 */
void __audit_log_capset(const struct cred *new, const struct cred *old)
{
        struct audit_context *context = current->audit_context;
        context->capset.pid = task_pid_nr(current);
        context->capset.cap.effective   = new->cap_effective;
        context->capset.cap.inheritable = new->cap_effective;
        context->capset.cap.permitted   = new->cap_permitted;
        context->type = AUDIT_CAPSET;
}

void __audit_mmap_fd(int fd, int flags)
{
        struct audit_context *context = current->audit_context;
        context->mmap.fd = fd;
        context->mmap.flags = flags;
        context->type = AUDIT_MMAP;
}

static void audit_log_task(struct audit_buffer *ab)
{
        kuid_t auid, uid;
        kgid_t gid;
        unsigned int sessionid;
        char comm[sizeof(current->comm)];

        auid = audit_get_loginuid(current);
        sessionid = audit_get_sessionid(current);
        current_uid_gid(&uid, &gid);

        audit_log_format(ab, "auid=%u uid=%u gid=%u ses=%u",
                         from_kuid(&init_user_ns, auid),
                         from_kuid(&init_user_ns, uid),
                         from_kgid(&init_user_ns, gid),
                         sessionid);
        audit_log_task_context(ab);
        audit_log_format(ab, " pid=%d comm=", task_pid_nr(current));
        audit_log_untrustedstring(ab, get_task_comm(comm, current));
        audit_log_d_path_exe(ab, current->mm);
}

/**
 * audit_core_dumps - record information about processes that end abnormally
 * @signr: signal value
 *
 * If a process ends with a core dump, something fishy is going on and we
 * should record the event for investigation.
 */
void audit_core_dumps(long signr)
{
        struct audit_buffer *ab;

        if (!audit_enabled)
                return;

        if (signr == SIGQUIT)   /* don't care for those */
                return;

        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_ANOM_ABEND);
        if (unlikely(!ab))
                return;
        audit_log_task(ab);
        audit_log_format(ab, " sig=%ld", signr);
        audit_log_end(ab);
}

void __audit_seccomp(unsigned long syscall, long signr, int code)
{
        struct audit_buffer *ab;

        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_SECCOMP);
        if (unlikely(!ab))
                return;
        audit_log_task(ab);
        audit_log_format(ab, " sig=%ld arch=%x syscall=%ld compat=%d ip=0x%lx code=0x%x",
                         signr, syscall_get_arch(), syscall,
                         in_compat_syscall(), KSTK_EIP(current), code);
        audit_log_end(ab);
}

struct list_head *audit_killed_trees(void)
{
        struct audit_context *ctx = current->audit_context;
        if (likely(!ctx || !ctx->in_syscall))
                return NULL;
        return &ctx->killed_trees;
}