/*
 * security/tomoyo/audit.c
 *
 * Copyright (C) 2005-2011  NTT DATA CORPORATION
 */

#include "common.h"
#include <linux/slab.h>

/**
 * tomoyo_print_bprm - Print "struct linux_binprm" for auditing.
 *
 * @bprm: Pointer to "struct linux_binprm".
 * @dump: Pointer to "struct tomoyo_page_dump".
 *
 * Returns the contents of @bprm on success, NULL otherwise.
 *
 * This function uses kzalloc(), so caller must kfree() if this function
 * didn't return NULL.
 */
static char *tomoyo_print_bprm(struct linux_binprm *bprm,
                               struct tomoyo_page_dump *dump)
{
        static const int tomoyo_buffer_len = 4096 * 2;
        char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
        char *cp;
        char *last_start;
        int len;
        unsigned long pos = bprm->p;
        int offset = pos % PAGE_SIZE;
        int argv_count = bprm->argc;
        int envp_count = bprm->envc;
        bool truncated = false;
        if (!buffer)
                return NULL;
        len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
        cp = buffer + len;
        if (!argv_count) {
                memmove(cp, "} envp[]={ ", 11);
                cp += 11;
        }
        last_start = cp;
        while (argv_count || envp_count) {
                if (!tomoyo_dump_page(bprm, pos, dump))
                        goto out;
                pos += PAGE_SIZE - offset;
                /* Read. */
                while (offset < PAGE_SIZE) {
                        const char *kaddr = dump->data;
                        const unsigned char c = kaddr[offset++];
                        if (cp == last_start)
                                *cp++ = '"';
                        if (cp >= buffer + tomoyo_buffer_len - 32) {
                                /* Reserve some room for "..." string. */
                                truncated = true;
                        } else if (c == '\\') {
                                *cp++ = '\\';
                                *cp++ = '\\';
                        } else if (c > ' ' && c < 127) {
                                *cp++ = c;
                        } else if (!c) {
                                *cp++ = '"';
                                *cp++ = ' ';
                                last_start = cp;
                        } else {
                                *cp++ = '\\';
                                *cp++ = (c >> 6) + '0';
                                *cp++ = ((c >> 3) & 7) + '0';
                                *cp++ = (c & 7) + '0';
                        }
                        if (c)
                                continue;
                        if (argv_count) {
                                if (--argv_count == 0) {
                                        if (truncated) {
                                                cp = last_start;
                                                memmove(cp, "... ", 4);
                                                cp += 4;
                                        }
                                        memmove(cp, "} envp[]={ ", 11);
                                        cp += 11;
                                        last_start = cp;
                                        truncated = false;
                                }
                        } else if (envp_count) {
                                if (--envp_count == 0) {
                                        if (truncated) {
                                                cp = last_start;
                                                memmove(cp, "... ", 4);
                                                cp += 4;
                                        }
                                }
                        }
                        if (!argv_count && !envp_count)
                                break;
                }
                offset = 0;
        }
        *cp++ = '}';
        *cp = '\0';
        return buffer;
out:
        snprintf(buffer, tomoyo_buffer_len - 1,
                 "argv[]={ ... } envp[]= { ... }");
        return buffer;
}

/**
 * tomoyo_filetype - Get string representation of file type.
 *
 * @mode: Mode value for stat().
 *
 * Returns file type string.
 */
static inline const char *tomoyo_filetype(const umode_t mode)
{
        switch (mode & S_IFMT) {
        case S_IFREG:
        case 0:
                return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
        case S_IFDIR:
                return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
        case S_IFLNK:
                return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
        case S_IFIFO:
                return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
        case S_IFSOCK:
                return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
        case S_IFBLK:
                return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
        case S_IFCHR:
                return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
        }
        return "unknown"; /* This should not happen. */
}

/**
 * tomoyo_print_header - Get header line of audit log.
 *
 * @r: Pointer to "struct tomoyo_request_info".
 *
 * Returns string representation.
 *
 * This function uses kmalloc(), so caller must kfree() if this function
 * didn't return NULL.
 */
static char *tomoyo_print_header(struct tomoyo_request_info *r)
{
        struct tomoyo_time stamp;
        const pid_t gpid = task_pid_nr(current);
        struct tomoyo_obj_info *obj = r->obj;
        static const int tomoyo_buffer_len = 4096;
        char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
        int pos;
        u8 i;
        if (!buffer)
                return NULL;
        {
                struct timeval tv;
                do_gettimeofday(&tv);
                tomoyo_convert_time(tv.tv_sec, &stamp);
        }
        pos = snprintf(buffer, tomoyo_buffer_len - 1,
                       "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
                       "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
                       "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
                       "fsuid=%u fsgid=%u }", stamp.year, stamp.month,
                       stamp.day, stamp.hour, stamp.min, stamp.sec, r->profile,
                       tomoyo_mode[r->mode], tomoyo_yesno(r->granted), gpid,
                       tomoyo_sys_getpid(), tomoyo_sys_getppid(),
                       from_kuid(&init_user_ns, current_uid()),
                       from_kgid(&init_user_ns, current_gid()),
                       from_kuid(&init_user_ns, current_euid()),
                       from_kgid(&init_user_ns, current_egid()),
                       from_kuid(&init_user_ns, current_suid()),
                       from_kgid(&init_user_ns, current_sgid()),
                       from_kuid(&init_user_ns, current_fsuid()),
                       from_kgid(&init_user_ns, current_fsgid()));
        if (!obj)
                goto no_obj_info;
        if (!obj->validate_done) {
                tomoyo_get_attributes(obj);
                obj->validate_done = true;
        }
        for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
                struct tomoyo_mini_stat *stat;
                unsigned int dev;
                umode_t mode;
                if (!obj->stat_valid[i])
                        continue;
                stat = &obj->stat[i];
                dev = stat->dev;
                mode = stat->mode;
                if (i & 1) {
                        pos += snprintf(buffer + pos,
                                        tomoyo_buffer_len - 1 - pos,
                                        " path%u.parent={ uid=%u gid=%u "
                                        "ino=%lu perm=0%o }", (i >> 1) + 1,
                                        from_kuid(&init_user_ns, stat->uid),
                                        from_kgid(&init_user_ns, stat->gid),
                                        (unsigned long)stat->ino,
                                        stat->mode & S_IALLUGO);
                        continue;
                }
                pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
                                " path%u={ uid=%u gid=%u ino=%lu major=%u"
                                " minor=%u perm=0%o type=%s", (i >> 1) + 1,
                                from_kuid(&init_user_ns, stat->uid),
                                from_kgid(&init_user_ns, stat->gid),
                                (unsigned long)stat->ino,
                                MAJOR(dev), MINOR(dev),
                                mode & S_IALLUGO, tomoyo_filetype(mode));
                if (S_ISCHR(mode) || S_ISBLK(mode)) {
                        dev = stat->rdev;
                        pos += snprintf(buffer + pos,
                                        tomoyo_buffer_len - 1 - pos,
                                        " dev_major=%u dev_minor=%u",
                                        MAJOR(dev), MINOR(dev));
                }
                pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
                                " }");
        }
no_obj_info:
        if (pos < tomoyo_buffer_len - 1)
                return buffer;
        kfree(buffer);
        return NULL;
}

/**
 * tomoyo_init_log - Allocate buffer for audit logs.
 *
 * @r:    Pointer to "struct tomoyo_request_info".
 * @len:  Buffer size needed for @fmt and @args.
 * @fmt:  The printf()'s format string.
 * @args: va_list structure for @fmt.
 *
 * Returns pointer to allocated memory.
 *
 * This function uses kzalloc(), so caller must kfree() if this function
 * didn't return NULL.
 */
char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
                      va_list args)
{
        char *buf = NULL;
        char *bprm_info = NULL;
        const char *header = NULL;
        char *realpath = NULL;
        const char *symlink = NULL;
        int pos;
        const char *domainname = r->domain->domainname->name;
        header = tomoyo_print_header(r);
        if (!header)
                return NULL;
        /* +10 is for '\n' etc. and '\0'. */
        len += strlen(domainname) + strlen(header) + 10;
        if (r->ee) {
                struct file *file = r->ee->bprm->file;
                realpath = tomoyo_realpath_from_path(&file->f_path);
                bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
                if (!realpath || !bprm_info)
                        goto out;
                /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
                len += strlen(realpath) + 80 + strlen(bprm_info);
        } else if (r->obj && r->obj->symlink_target) {
                symlink = r->obj->symlink_target->name;
                /* +18 is for " symlink.target=\"%s\"" */
                len += 18 + strlen(symlink);
        }
        len = tomoyo_round2(len);
        buf = kzalloc(len, GFP_NOFS);
        if (!buf)
                goto out;
        len--;
        pos = snprintf(buf, len, "%s", header);
        if (realpath) {
                struct linux_binprm *bprm = r->ee->bprm;
                pos += snprintf(buf + pos, len - pos,
                                " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
                                realpath, bprm->argc, bprm->envc, bprm_info);
        } else if (symlink)
                pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
                                symlink);
        pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
        vsnprintf(buf + pos, len - pos, fmt, args);
out:
        kfree(realpath);
        kfree(bprm_info);
        kfree(header);
        return buf;
}

/* Wait queue for /sys/kernel/security/tomoyo/audit. */
static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);

/* Structure for audit log. */
struct tomoyo_log {
        struct list_head list;
        char *log;
        int size;
};

/* The list for "struct tomoyo_log". */
static LIST_HEAD(tomoyo_log);

/* Lock for "struct list_head tomoyo_log". */
static DEFINE_SPINLOCK(tomoyo_log_lock);

/* Length of "stuct list_head tomoyo_log". */
static unsigned int tomoyo_log_count;

/**
 * tomoyo_get_audit - Get audit mode.
 *
 * @ns:          Pointer to "struct tomoyo_policy_namespace".
 * @profile:     Profile number.
 * @index:       Index number of functionality.
 * @is_granted:  True if granted log, false otherwise.
 *
 * Returns true if this request should be audited, false otherwise.
 */
static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
                             const u8 profile, const u8 index,
                             const struct tomoyo_acl_info *matched_acl,
                             const bool is_granted)
{
        u8 mode;
        const u8 category = tomoyo_index2category[index] +
                TOMOYO_MAX_MAC_INDEX;
        struct tomoyo_profile *p;
        if (!tomoyo_policy_loaded)
                return false;
        p = tomoyo_profile(ns, profile);
        if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
                return false;
        if (is_granted && matched_acl && matched_acl->cond &&
            matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
                return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
        mode = p->config[index];
        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
                mode = p->config[category];
        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
                mode = p->default_config;
        if (is_granted)
                return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
        return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
}

/**
 * tomoyo_write_log2 - Write an audit log.
 *
 * @r:    Pointer to "struct tomoyo_request_info".
 * @len:  Buffer size needed for @fmt and @args.
 * @fmt:  The printf()'s format string.
 * @args: va_list structure for @fmt.
 *
 * Returns nothing.
 */
void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
                       va_list args)
{
        char *buf;
        struct tomoyo_log *entry;
        bool quota_exceeded = false;
        if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
                              r->matched_acl, r->granted))
                goto out;
        buf = tomoyo_init_log(r, len, fmt, args);
        if (!buf)
                goto out;
        entry = kzalloc(sizeof(*entry), GFP_NOFS);
        if (!entry) {
                kfree(buf);
                goto out;
        }
        entry->log = buf;
        len = tomoyo_round2(strlen(buf) + 1);
        /*
         * The entry->size is used for memory quota checks.
         * Don't go beyond strlen(entry->log).
         */
        entry->size = len + tomoyo_round2(sizeof(*entry));
        spin_lock(&tomoyo_log_lock);
        if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
            tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
            tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
                quota_exceeded = true;
        } else {
                tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
                list_add_tail(&entry->list, &tomoyo_log);
                tomoyo_log_count++;
        }
        spin_unlock(&tomoyo_log_lock);
        if (quota_exceeded) {
                kfree(buf);
                kfree(entry);
                goto out;
        }
        wake_up(&tomoyo_log_wait);
out:
        return;
}

/**
 * tomoyo_write_log - Write an audit log.
 *
 * @r:   Pointer to "struct tomoyo_request_info".
 * @fmt: The printf()'s format string, followed by parameters.
 *
 * Returns nothing.
 */
void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
{
        va_list args;
        int len;
        va_start(args, fmt);
        len = vsnprintf((char *) &len, 1, fmt, args) + 1;
        va_end(args);
        va_start(args, fmt);
        tomoyo_write_log2(r, len, fmt, args);
        va_end(args);
}

/**
 * tomoyo_read_log - Read an audit log.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns nothing.
 */
void tomoyo_read_log(struct tomoyo_io_buffer *head)
{
        struct tomoyo_log *ptr = NULL;
        if (head->r.w_pos)
                return;
        kfree(head->read_buf);
        head->read_buf = NULL;
        spin_lock(&tomoyo_log_lock);
        if (!list_empty(&tomoyo_log)) {
                ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
                list_del(&ptr->list);
                tomoyo_log_count--;
                tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
        }
        spin_unlock(&tomoyo_log_lock);
        if (ptr) {
                head->read_buf = ptr->log;
                head->r.w[head->r.w_pos++] = head->read_buf;
                kfree(ptr);
        }
}

/**
 * tomoyo_poll_log - Wait for an audit log.
 *
 * @file: Pointer to "struct file".
 * @wait: Pointer to "poll_table". Maybe NULL.
 *
 * Returns POLLIN | POLLRDNORM when ready to read an audit log.
 */
unsigned int tomoyo_poll_log(struct file *file, poll_table *wait)
{
        if (tomoyo_log_count)
                return POLLIN | POLLRDNORM;
        poll_wait(file, &tomoyo_log_wait, wait);
        if (tomoyo_log_count)
                return POLLIN | POLLRDNORM;
        return 0;
}