// SPDX-License-Identifier: GPL-2.0
/*
 * security/tomoyo/util.c
 *
 * Copyright (C) 2005-2011  NTT DATA CORPORATION
 */

#include <linux/slab.h>
#include <linux/rculist.h>

#include "common.h"

/* Lock for protecting policy. */
DEFINE_MUTEX(tomoyo_policy_lock);

/* Has /sbin/init started? */
bool tomoyo_policy_loaded;

/*
 * Mapping table from "enum tomoyo_mac_index" to
 * "enum tomoyo_mac_category_index".
 */
const u8 tomoyo_index2category[TOMOYO_MAX_MAC_INDEX] = {
        /* CONFIG::file group */
        [TOMOYO_MAC_FILE_EXECUTE]    = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_OPEN]       = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_CREATE]     = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_UNLINK]     = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_GETATTR]    = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_MKDIR]      = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_RMDIR]      = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_MKFIFO]     = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_MKSOCK]     = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_TRUNCATE]   = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_SYMLINK]    = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_MKBLOCK]    = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_MKCHAR]     = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_LINK]       = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_RENAME]     = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_CHMOD]      = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_CHOWN]      = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_CHGRP]      = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_IOCTL]      = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_CHROOT]     = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_MOUNT]      = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_UMOUNT]     = TOMOYO_MAC_CATEGORY_FILE,
        [TOMOYO_MAC_FILE_PIVOT_ROOT] = TOMOYO_MAC_CATEGORY_FILE,
        /* CONFIG::network group */
        [TOMOYO_MAC_NETWORK_INET_STREAM_BIND]       =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_INET_STREAM_LISTEN]     =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_INET_STREAM_CONNECT]    =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_INET_DGRAM_BIND]        =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_INET_DGRAM_SEND]        =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_INET_RAW_BIND]          =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_INET_RAW_SEND]          =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_UNIX_STREAM_BIND]       =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_UNIX_STREAM_LISTEN]     =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_UNIX_STREAM_CONNECT]    =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_UNIX_DGRAM_BIND]        =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_UNIX_DGRAM_SEND]        =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_UNIX_SEQPACKET_BIND]    =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_UNIX_SEQPACKET_LISTEN]  =
        TOMOYO_MAC_CATEGORY_NETWORK,
        [TOMOYO_MAC_NETWORK_UNIX_SEQPACKET_CONNECT] =
        TOMOYO_MAC_CATEGORY_NETWORK,
        /* CONFIG::misc group */
        [TOMOYO_MAC_ENVIRON]         = TOMOYO_MAC_CATEGORY_MISC,
};

/**
 * tomoyo_convert_time - Convert time_t to YYYY/MM/DD hh/mm/ss.
 *
 * @time64: Seconds since 1970/01/01 00:00:00.
 * @stamp:  Pointer to "struct tomoyo_time".
 *
 * Returns nothing.
 */
void tomoyo_convert_time(time64_t time64, struct tomoyo_time *stamp)
{
        struct tm tm;

        time64_to_tm(time64, 0, &tm);
        stamp->sec = tm.tm_sec;
        stamp->min = tm.tm_min;
        stamp->hour = tm.tm_hour;
        stamp->day = tm.tm_mday;
        stamp->month = tm.tm_mon + 1;
        stamp->year = tm.tm_year + 1900;
}

/**
 * tomoyo_permstr - Find permission keywords.
 *
 * @string: String representation for permissions in foo/bar/buz format.
 * @keyword: Keyword to find from @string/
 *
 * Returns true if @keyword was found in @string, false otherwise.
 *
 * This function assumes that strncmp(w1, w2, strlen(w1)) != 0 if w1 != w2.
 */
bool tomoyo_permstr(const char *string, const char *keyword)
{
        const char *cp = strstr(string, keyword);

        if (cp)
                return cp == string || *(cp - 1) == '/';
        return false;
}

/**
 * tomoyo_read_token - Read a word from a line.
 *
 * @param: Pointer to "struct tomoyo_acl_param".
 *
 * Returns a word on success, "" otherwise.
 *
 * To allow the caller to skip NULL check, this function returns "" rather than
 * NULL if there is no more words to read.
 */
char *tomoyo_read_token(struct tomoyo_acl_param *param)
{
        char *pos = param->data;
        char *del = strchr(pos, ' ');

        if (del)
                *del++ = '\0';
        else
                del = pos + strlen(pos);
        param->data = del;
        return pos;
}

static bool tomoyo_correct_path2(const char *filename, const size_t len);

/**
 * tomoyo_get_domainname - Read a domainname from a line.
 *
 * @param: Pointer to "struct tomoyo_acl_param".
 *
 * Returns a domainname on success, NULL otherwise.
 */
const struct tomoyo_path_info *tomoyo_get_domainname
(struct tomoyo_acl_param *param)
{
        char *start = param->data;
        char *pos = start;

        while (*pos) {
                if (*pos++ != ' ' ||
                    tomoyo_correct_path2(pos, strchrnul(pos, ' ') - pos))
                        continue;
                *(pos - 1) = '\0';
                break;
        }
        param->data = pos;
        if (tomoyo_correct_domain(start))
                return tomoyo_get_name(start);
        return NULL;
}

/**
 * tomoyo_parse_ulong - Parse an "unsigned long" value.
 *
 * @result: Pointer to "unsigned long".
 * @str:    Pointer to string to parse.
 *
 * Returns one of values in "enum tomoyo_value_type".
 *
 * The @src is updated to point the first character after the value
 * on success.
 */
u8 tomoyo_parse_ulong(unsigned long *result, char **str)
{
        const char *cp = *str;
        char *ep;
        int base = 10;

        if (*cp == '0') {
                char c = *(cp + 1);

                if (c == 'x' || c == 'X') {
                        base = 16;
                        cp += 2;
                } else if (c >= '0' && c <= '7') {
                        base = 8;
                        cp++;
                }
        }
        *result = simple_strtoul(cp, &ep, base);
        if (cp == ep)
                return TOMOYO_VALUE_TYPE_INVALID;
        *str = ep;
        switch (base) {
        case 16:
                return TOMOYO_VALUE_TYPE_HEXADECIMAL;
        case 8:
                return TOMOYO_VALUE_TYPE_OCTAL;
        default:
                return TOMOYO_VALUE_TYPE_DECIMAL;
        }
}

/**
 * tomoyo_print_ulong - Print an "unsigned long" value.
 *
 * @buffer:     Pointer to buffer.
 * @buffer_len: Size of @buffer.
 * @value:      An "unsigned long" value.
 * @type:       Type of @value.
 *
 * Returns nothing.
 */
void tomoyo_print_ulong(char *buffer, const int buffer_len,
                        const unsigned long value, const u8 type)
{
        if (type == TOMOYO_VALUE_TYPE_DECIMAL)
                snprintf(buffer, buffer_len, "%lu", value);
        else if (type == TOMOYO_VALUE_TYPE_OCTAL)
                snprintf(buffer, buffer_len, "0%lo", value);
        else if (type == TOMOYO_VALUE_TYPE_HEXADECIMAL)
                snprintf(buffer, buffer_len, "0x%lX", value);
        else
                snprintf(buffer, buffer_len, "type(%u)", type);
}

/**
 * tomoyo_parse_name_union - Parse a tomoyo_name_union.
 *
 * @param: Pointer to "struct tomoyo_acl_param".
 * @ptr:   Pointer to "struct tomoyo_name_union".
 *
 * Returns true on success, false otherwise.
 */
bool tomoyo_parse_name_union(struct tomoyo_acl_param *param,
                             struct tomoyo_name_union *ptr)
{
        char *filename;

        if (param->data[0] == '@') {
                param->data++;
                ptr->group = tomoyo_get_group(param, TOMOYO_PATH_GROUP);
                return ptr->group != NULL;
        }
        filename = tomoyo_read_token(param);
        if (!tomoyo_correct_word(filename))
                return false;
        ptr->filename = tomoyo_get_name(filename);
        return ptr->filename != NULL;
}

/**
 * tomoyo_parse_number_union - Parse a tomoyo_number_union.
 *
 * @param: Pointer to "struct tomoyo_acl_param".
 * @ptr:   Pointer to "struct tomoyo_number_union".
 *
 * Returns true on success, false otherwise.
 */
bool tomoyo_parse_number_union(struct tomoyo_acl_param *param,
                               struct tomoyo_number_union *ptr)
{
        char *data;
        u8 type;
        unsigned long v;

        memset(ptr, 0, sizeof(*ptr));
        if (param->data[0] == '@') {
                param->data++;
                ptr->group = tomoyo_get_group(param, TOMOYO_NUMBER_GROUP);
                return ptr->group != NULL;
        }
        data = tomoyo_read_token(param);
        type = tomoyo_parse_ulong(&v, &data);
        if (type == TOMOYO_VALUE_TYPE_INVALID)
                return false;
        ptr->values[0] = v;
        ptr->value_type[0] = type;
        if (!*data) {
                ptr->values[1] = v;
                ptr->value_type[1] = type;
                return true;
        }
        if (*data++ != '-')
                return false;
        type = tomoyo_parse_ulong(&v, &data);
        if (type == TOMOYO_VALUE_TYPE_INVALID || *data || ptr->values[0] > v)
                return false;
        ptr->values[1] = v;
        ptr->value_type[1] = type;
        return true;
}

/**
 * tomoyo_byte_range - Check whether the string is a \ooo style octal value.
 *
 * @str: Pointer to the string.
 *
 * Returns true if @str is a \ooo style octal value, false otherwise.
 *
 * TOMOYO uses \ooo style representation for 0x01 - 0x20 and 0x7F - 0xFF.
 * This function verifies that \ooo is in valid range.
 */
static inline bool tomoyo_byte_range(const char *str)
{
        return *str >= '0' && *str++ <= '3' &&
                *str >= '0' && *str++ <= '7' &&
                *str >= '0' && *str <= '7';
}

/**
 * tomoyo_alphabet_char - Check whether the character is an alphabet.
 *
 * @c: The character to check.
 *
 * Returns true if @c is an alphabet character, false otherwise.
 */
static inline bool tomoyo_alphabet_char(const char c)
{
        return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
}

/**
 * tomoyo_make_byte - Make byte value from three octal characters.
 *
 * @c1: The first character.
 * @c2: The second character.
 * @c3: The third character.
 *
 * Returns byte value.
 */
static inline u8 tomoyo_make_byte(const u8 c1, const u8 c2, const u8 c3)
{
        return ((c1 - '0') << 6) + ((c2 - '0') << 3) + (c3 - '0');
}

/**
 * tomoyo_valid - Check whether the character is a valid char.
 *
 * @c: The character to check.
 *
 * Returns true if @c is a valid character, false otherwise.
 */
static inline bool tomoyo_valid(const unsigned char c)
{
        return c > ' ' && c < 127;
}

/**
 * tomoyo_invalid - Check whether the character is an invalid char.
 *
 * @c: The character to check.
 *
 * Returns true if @c is an invalid character, false otherwise.
 */
static inline bool tomoyo_invalid(const unsigned char c)
{
        return c && (c <= ' ' || c >= 127);
}

/**
 * tomoyo_str_starts - Check whether the given string starts with the given keyword.
 *
 * @src:  Pointer to pointer to the string.
 * @find: Pointer to the keyword.
 *
 * Returns true if @src starts with @find, false otherwise.
 *
 * The @src is updated to point the first character after the @find
 * if @src starts with @find.
 */
bool tomoyo_str_starts(char **src, const char *find)
{
        const int len = strlen(find);
        char *tmp = *src;

        if (strncmp(tmp, find, len))
                return false;
        tmp += len;
        *src = tmp;
        return true;
}

/**
 * tomoyo_normalize_line - Format string.
 *
 * @buffer: The line to normalize.
 *
 * Leading and trailing whitespaces are removed.
 * Multiple whitespaces are packed into single space.
 *
 * Returns nothing.
 */
void tomoyo_normalize_line(unsigned char *buffer)
{
        unsigned char *sp = buffer;
        unsigned char *dp = buffer;
        bool first = true;

        while (tomoyo_invalid(*sp))
                sp++;
        while (*sp) {
                if (!first)
                        *dp++ = ' ';
                first = false;
                while (tomoyo_valid(*sp))
                        *dp++ = *sp++;
                while (tomoyo_invalid(*sp))
                        sp++;
        }
        *dp = '\0';
}

/**
 * tomoyo_correct_word2 - Validate a string.
 *
 * @string: The string to check. Maybe non-'\0'-terminated.
 * @len:    Length of @string.
 *
 * Check whether the given string follows the naming rules.
 * Returns true if @string follows the naming rules, false otherwise.
 */
static bool tomoyo_correct_word2(const char *string, size_t len)
{
        u8 recursion = 20;
        const char *const start = string;
        bool in_repetition = false;

        if (!len)
                goto out;
        while (len--) {
                unsigned char c = *string++;

                if (c == '\\') {
                        if (!len--)
                                goto out;
                        c = *string++;
                        if (c >= '0' && c <= '3') {
                                unsigned char d;
                                unsigned char e;

                                if (!len-- || !len--)
                                        goto out;
                                d = *string++;
                                e = *string++;
                                if (d < '0' || d > '7' || e < '0' || e > '7')
                                        goto out;
                                c = tomoyo_make_byte(c, d, e);
                                if (c <= ' ' || c >= 127)
                                        continue;
                                goto out;
                        }
                        switch (c) {
                        case '\\':  /* "\\" */
                        case '+':   /* "\+" */
                        case '?':   /* "\?" */
                        case 'x':   /* "\x" */
                        case 'a':   /* "\a" */
                        case '-':   /* "\-" */
                                continue;
                        }
                        if (!recursion--)
                                goto out;
                        switch (c) {
                        case '*':   /* "\*" */
                        case '@':   /* "\@" */
                        case '$':   /* "\$" */
                        case 'X':   /* "\X" */
                        case 'A':   /* "\A" */
                                continue;
                        case '{':   /* "/\{" */
                                if (string - 3 < start || *(string - 3) != '/')
                                        goto out;
                                in_repetition = true;
                                continue;
                        case '}':   /* "\}/" */
                                if (*string != '/')
                                        goto out;
                                if (!in_repetition)
                                        goto out;
                                in_repetition = false;
                                continue;
                        }
                        goto out;
                } else if (in_repetition && c == '/') {
                        goto out;
                } else if (c <= ' ' || c >= 127) {
                        goto out;
                }
        }
        if (in_repetition)
                goto out;
        return true;
 out:
        return false;
}

/**
 * tomoyo_correct_word - Validate a string.
 *
 * @string: The string to check.
 *
 * Check whether the given string follows the naming rules.
 * Returns true if @string follows the naming rules, false otherwise.
 */
bool tomoyo_correct_word(const char *string)
{
        return tomoyo_correct_word2(string, strlen(string));
}

/**
 * tomoyo_correct_path2 - Check whether the given pathname follows the naming rules.
 *
 * @filename: The pathname to check.
 * @len:      Length of @filename.
 *
 * Returns true if @filename follows the naming rules, false otherwise.
 */
static bool tomoyo_correct_path2(const char *filename, const size_t len)
{
        const char *cp1 = memchr(filename, '/', len);
        const char *cp2 = memchr(filename, '.', len);

        return cp1 && (!cp2 || (cp1 < cp2)) && tomoyo_correct_word2(filename, len);
}

/**
 * tomoyo_correct_path - Validate a pathname.
 *
 * @filename: The pathname to check.
 *
 * Check whether the given pathname follows the naming rules.
 * Returns true if @filename follows the naming rules, false otherwise.
 */
bool tomoyo_correct_path(const char *filename)
{
        return tomoyo_correct_path2(filename, strlen(filename));
}

/**
 * tomoyo_correct_domain - Check whether the given domainname follows the naming rules.
 *
 * @domainname: The domainname to check.
 *
 * Returns true if @domainname follows the naming rules, false otherwise.
 */
bool tomoyo_correct_domain(const unsigned char *domainname)
{
        if (!domainname || !tomoyo_domain_def(domainname))
                return false;
        domainname = strchr(domainname, ' ');
        if (!domainname++)
                return true;
        while (1) {
                const unsigned char *cp = strchr(domainname, ' ');

                if (!cp)
                        break;
                if (!tomoyo_correct_path2(domainname, cp - domainname))
                        return false;
                domainname = cp + 1;
        }
        return tomoyo_correct_path(domainname);
}

/**
 * tomoyo_domain_def - Check whether the given token can be a domainname.
 *
 * @buffer: The token to check.
 *
 * Returns true if @buffer possibly be a domainname, false otherwise.
 */
bool tomoyo_domain_def(const unsigned char *buffer)
{
        const unsigned char *cp;
        int len;

        if (*buffer != '<')
                return false;
        cp = strchr(buffer, ' ');
        if (!cp)
                len = strlen(buffer);
        else
                len = cp - buffer;
        if (buffer[len - 1] != '>' ||
            !tomoyo_correct_word2(buffer + 1, len - 2))
                return false;
        return true;
}

/**
 * tomoyo_find_domain - Find a domain by the given name.
 *
 * @domainname: The domainname to find.
 *
 * Returns pointer to "struct tomoyo_domain_info" if found, NULL otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
struct tomoyo_domain_info *tomoyo_find_domain(const char *domainname)
{
        struct tomoyo_domain_info *domain;
        struct tomoyo_path_info name;

        name.name = domainname;
        tomoyo_fill_path_info(&name);
        list_for_each_entry_rcu(domain, &tomoyo_domain_list, list,
                                srcu_read_lock_held(&tomoyo_ss)) {
                if (!domain->is_deleted &&
                    !tomoyo_pathcmp(&name, domain->domainname))
                        return domain;
        }
        return NULL;
}

/**
 * tomoyo_const_part_length - Evaluate the initial length without a pattern in a token.
 *
 * @filename: The string to evaluate.
 *
 * Returns the initial length without a pattern in @filename.
 */
static int tomoyo_const_part_length(const char *filename)
{
        char c;
        int len = 0;

        if (!filename)
                return 0;
        while ((c = *filename++) != '\0') {
                if (c != '\\') {
                        len++;
                        continue;
                }
                c = *filename++;
                switch (c) {
                case '\\':  /* "\\" */
                        len += 2;
                        continue;
                case '0':   /* "\ooo" */
                case '1':
                case '2':
                case '3':
                        c = *filename++;
                        if (c < '0' || c > '7')
                                break;
                        c = *filename++;
                        if (c < '0' || c > '7')
                                break;
                        len += 4;
                        continue;
                }
                break;
        }
        return len;
}

/**
 * tomoyo_fill_path_info - Fill in "struct tomoyo_path_info" members.
 *
 * @ptr: Pointer to "struct tomoyo_path_info" to fill in.
 *
 * The caller sets "struct tomoyo_path_info"->name.
 */
void tomoyo_fill_path_info(struct tomoyo_path_info *ptr)
{
        const char *name = ptr->name;
        const int len = strlen(name);

        ptr->const_len = tomoyo_const_part_length(name);
        ptr->is_dir = len && (name[len - 1] == '/');
        ptr->is_patterned = (ptr->const_len < len);
        ptr->hash = full_name_hash(NULL, name, len);
}

/**
 * tomoyo_file_matches_pattern2 - Pattern matching without '/' character and "\-" pattern.
 *
 * @filename:     The start of string to check.
 * @filename_end: The end of string to check.
 * @pattern:      The start of pattern to compare.
 * @pattern_end:  The end of pattern to compare.
 *
 * Returns true if @filename matches @pattern, false otherwise.
 */
static bool tomoyo_file_matches_pattern2(const char *filename,
                                         const char *filename_end,
                                         const char *pattern,
                                         const char *pattern_end)
{
        while (filename < filename_end && pattern < pattern_end) {
                char c;
                int i;
                int j;

                if (*pattern != '\\') {
                        if (*filename++ != *pattern++)
                                return false;
                        continue;
                }
                c = *filename;
                pattern++;
                switch (*pattern) {
                case '?':
                        if (c == '/') {
                                return false;
                        } else if (c == '\\') {
                                if (filename[1] == '\\')
                                        filename++;
                                else if (tomoyo_byte_range(filename + 1))
                                        filename += 3;
                                else
                                        return false;
                        }
                        break;
                case '\\':
                        if (c != '\\')
                                return false;
                        if (*++filename != '\\')
                                return false;
                        break;
                case '+':
                        if (!isdigit(c))
                                return false;
                        break;
                case 'x':
                        if (!isxdigit(c))
                                return false;
                        break;
                case 'a':
                        if (!tomoyo_alphabet_char(c))
                                return false;
                        break;
                case '0':
                case '1':
                case '2':
                case '3':
                        if (c == '\\' && tomoyo_byte_range(filename + 1)
                            && strncmp(filename + 1, pattern, 3) == 0) {
                                filename += 3;
                                pattern += 2;
                                break;
                        }
                        return false; /* Not matched. */
                case '*':
                case '@':
                        for (i = 0; i <= filename_end - filename; i++) {
                                if (tomoyo_file_matches_pattern2(
                                                    filename + i, filename_end,
                                                    pattern + 1, pattern_end))
                                        return true;
                                c = filename[i];
                                if (c == '.' && *pattern == '@')
                                        break;
                                if (c != '\\')
                                        continue;
                                if (filename[i + 1] == '\\')
                                        i++;
                                else if (tomoyo_byte_range(filename + i + 1))
                                        i += 3;
                                else
                                        break; /* Bad pattern. */
                        }
                        return false; /* Not matched. */
                default:
                        j = 0;
                        c = *pattern;
                        if (c == '$') {
                                while (isdigit(filename[j]))
                                        j++;
                        } else if (c == 'X') {
                                while (isxdigit(filename[j]))
                                        j++;
                        } else if (c == 'A') {
                                while (tomoyo_alphabet_char(filename[j]))
                                        j++;
                        }
                        for (i = 1; i <= j; i++) {
                                if (tomoyo_file_matches_pattern2(
                                                    filename + i, filename_end,
                                                    pattern + 1, pattern_end))
                                        return true;
                        }
                        return false; /* Not matched or bad pattern. */
                }
                filename++;
                pattern++;
        }
        while (*pattern == '\\' &&
               (*(pattern + 1) == '*' || *(pattern + 1) == '@'))
                pattern += 2;
        return filename == filename_end && pattern == pattern_end;
}

/**
 * tomoyo_file_matches_pattern - Pattern matching without '/' character.
 *
 * @filename:     The start of string to check.
 * @filename_end: The end of string to check.
 * @pattern:      The start of pattern to compare.
 * @pattern_end:  The end of pattern to compare.
 *
 * Returns true if @filename matches @pattern, false otherwise.
 */
static bool tomoyo_file_matches_pattern(const char *filename,
                                        const char *filename_end,
                                        const char *pattern,
                                        const char *pattern_end)
{
        const char *pattern_start = pattern;
        bool first = true;
        bool result;

        while (pattern < pattern_end - 1) {
                /* Split at "\-" pattern. */
                if (*pattern++ != '\\' || *pattern++ != '-')
                        continue;
                result = tomoyo_file_matches_pattern2(filename,
                                                      filename_end,
                                                      pattern_start,
                                                      pattern - 2);
                if (first)
                        result = !result;
                if (result)
                        return false;
                first = false;
                pattern_start = pattern;
        }
        result = tomoyo_file_matches_pattern2(filename, filename_end,
                                              pattern_start, pattern_end);
        return first ? result : !result;
}

/**
 * tomoyo_path_matches_pattern2 - Do pathname pattern matching.
 *
 * @f: The start of string to check.
 * @p: The start of pattern to compare.
 *
 * Returns true if @f matches @p, false otherwise.
 */
static bool tomoyo_path_matches_pattern2(const char *f, const char *p)
{
        const char *f_delimiter;
        const char *p_delimiter;

        while (*f && *p) {
                f_delimiter = strchr(f, '/');
                if (!f_delimiter)
                        f_delimiter = f + strlen(f);
                p_delimiter = strchr(p, '/');
                if (!p_delimiter)
                        p_delimiter = p + strlen(p);
                if (*p == '\\' && *(p + 1) == '{')
                        goto recursive;
                if (!tomoyo_file_matches_pattern(f, f_delimiter, p,
                                                 p_delimiter))
                        return false;
                f = f_delimiter;
                if (*f)
                        f++;
                p = p_delimiter;
                if (*p)
                        p++;
        }
        /* Ignore trailing "\*" and "\@" in @pattern. */
        while (*p == '\\' &&
               (*(p + 1) == '*' || *(p + 1) == '@'))
                p += 2;
        return !*f && !*p;
 recursive:
        /*
         * The "\{" pattern is permitted only after '/' character.
         * This guarantees that below "*(p - 1)" is safe.
         * Also, the "\}" pattern is permitted only before '/' character
         * so that "\{" + "\}" pair will not break the "\-" operator.
         */
        if (*(p - 1) != '/' || p_delimiter <= p + 3 || *p_delimiter != '/' ||
            *(p_delimiter - 1) != '}' || *(p_delimiter - 2) != '\\')
                return false; /* Bad pattern. */
        do {
                /* Compare current component with pattern. */
                if (!tomoyo_file_matches_pattern(f, f_delimiter, p + 2,
                                                 p_delimiter - 2))
                        break;
                /* Proceed to next component. */
                f = f_delimiter;
                if (!*f)
                        break;
                f++;
                /* Continue comparison. */
                if (tomoyo_path_matches_pattern2(f, p_delimiter + 1))
                        return true;
                f_delimiter = strchr(f, '/');
        } while (f_delimiter);
        return false; /* Not matched. */
}

/**
 * tomoyo_path_matches_pattern - Check whether the given filename matches the given pattern.
 *
 * @filename: The filename to check.
 * @pattern:  The pattern to compare.
 *
 * Returns true if matches, false otherwise.
 *
 * The following patterns are available.
 *   \\     \ itself.
 *   \ooo   Octal representation of a byte.
 *   \*     Zero or more repetitions of characters other than '/'.
 *   \@     Zero or more repetitions of characters other than '/' or '.'.
 *   \?     1 byte character other than '/'.
 *   \$     One or more repetitions of decimal digits.
 *   \+     1 decimal digit.
 *   \X     One or more repetitions of hexadecimal digits.
 *   \x     1 hexadecimal digit.
 *   \A     One or more repetitions of alphabet characters.
 *   \a     1 alphabet character.
 *
 *   \-     Subtraction operator.
 *
 *   /\{dir\}/   '/' + 'One or more repetitions of dir/' (e.g. /dir/ /dir/dir/
 *               /dir/dir/dir/ ).
 */
bool tomoyo_path_matches_pattern(const struct tomoyo_path_info *filename,
                                 const struct tomoyo_path_info *pattern)
{
        const char *f = filename->name;
        const char *p = pattern->name;
        const int len = pattern->const_len;

        /* If @pattern doesn't contain pattern, I can use strcmp(). */
        if (!pattern->is_patterned)
                return !tomoyo_pathcmp(filename, pattern);
        /* Don't compare directory and non-directory. */
        if (filename->is_dir != pattern->is_dir)
                return false;
        /* Compare the initial length without patterns. */
        if (strncmp(f, p, len))
                return false;
        f += len;
        p += len;
        return tomoyo_path_matches_pattern2(f, p);
}

/**
 * tomoyo_get_exe - Get tomoyo_realpath() of current process.
 *
 * Returns the tomoyo_realpath() of current process on success, NULL otherwise.
 *
 * This function uses kzalloc(), so the caller must call kfree()
 * if this function didn't return NULL.
 */
const char *tomoyo_get_exe(void)
{
        struct file *exe_file;
        const char *cp;
        struct mm_struct *mm = current->mm;

        if (!mm)
                return NULL;
        exe_file = get_mm_exe_file(mm);
        if (!exe_file)
                return NULL;

        cp = tomoyo_realpath_from_path(&exe_file->f_path);
        fput(exe_file);
        return cp;
}

/**
 * tomoyo_get_mode - Get MAC mode.
 *
 * @ns:      Pointer to "struct tomoyo_policy_namespace".
 * @profile: Profile number.
 * @index:   Index number of functionality.
 *
 * Returns mode.
 */
int tomoyo_get_mode(const struct tomoyo_policy_namespace *ns, const u8 profile,
                    const u8 index)
{
        u8 mode;
        struct tomoyo_profile *p;

        if (!tomoyo_policy_loaded)
                return TOMOYO_CONFIG_DISABLED;
        p = tomoyo_profile(ns, profile);

        mode = p->config[index];
        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
                mode = p->config[tomoyo_index2category[index]
                                 + TOMOYO_MAX_MAC_INDEX];
        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
                mode = p->default_config;
        return mode & 3;
}

/**
 * tomoyo_init_request_info - Initialize "struct tomoyo_request_info" members.
 *
 * @r:      Pointer to "struct tomoyo_request_info" to initialize.
 * @domain: Pointer to "struct tomoyo_domain_info". NULL for tomoyo_domain().
 * @index:  Index number of functionality.
 *
 * Returns mode.
 */
int tomoyo_init_request_info(struct tomoyo_request_info *r,
                             struct tomoyo_domain_info *domain, const u8 index)
{
        u8 profile;

        memset(r, 0, sizeof(*r));
        if (!domain)
                domain = tomoyo_domain();
        r->domain = domain;
        profile = domain->profile;
        r->profile = profile;
        r->type = index;
        r->mode = tomoyo_get_mode(domain->ns, profile, index);
        return r->mode;
}

/**
 * tomoyo_domain_quota_is_ok - Check for domain's quota.
 *
 * @r: Pointer to "struct tomoyo_request_info".
 *
 * Returns true if the domain is not exceeded quota, false otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
bool tomoyo_domain_quota_is_ok(struct tomoyo_request_info *r)
{
        unsigned int count = 0;
        struct tomoyo_domain_info *domain = r->domain;
        struct tomoyo_acl_info *ptr;

        if (r->mode != TOMOYO_CONFIG_LEARNING)
                return false;
        if (!domain)
                return true;
        list_for_each_entry_rcu(ptr, &domain->acl_info_list, list,
                                srcu_read_lock_held(&tomoyo_ss)) {
                u16 perm;
                u8 i;

                if (ptr->is_deleted)
                        continue;
                /*
                 * Reading perm bitmap might race with tomoyo_merge_*() because
                 * caller does not hold tomoyo_policy_lock mutex. But exceeding
                 * max_learning_entry parameter by a few entries does not harm.
                 */
                switch (ptr->type) {
                case TOMOYO_TYPE_PATH_ACL:
                        data_race(perm = container_of(ptr, struct tomoyo_path_acl, head)->perm);
                        break;
                case TOMOYO_TYPE_PATH2_ACL:
                        data_race(perm = container_of(ptr, struct tomoyo_path2_acl, head)->perm);
                        break;
                case TOMOYO_TYPE_PATH_NUMBER_ACL:
                        data_race(perm = container_of(ptr, struct tomoyo_path_number_acl, head)
                                  ->perm);
                        break;
                case TOMOYO_TYPE_MKDEV_ACL:
                        data_race(perm = container_of(ptr, struct tomoyo_mkdev_acl, head)->perm);
                        break;
                case TOMOYO_TYPE_INET_ACL:
                        data_race(perm = container_of(ptr, struct tomoyo_inet_acl, head)->perm);
                        break;
                case TOMOYO_TYPE_UNIX_ACL:
                        data_race(perm = container_of(ptr, struct tomoyo_unix_acl, head)->perm);
                        break;
                case TOMOYO_TYPE_MANUAL_TASK_ACL:
                        perm = 0;
                        break;
                default:
                        perm = 1;
                }
                for (i = 0; i < 16; i++)
                        if (perm & (1 << i))
                                count++;
        }
        if (count < tomoyo_profile(domain->ns, domain->profile)->
            pref[TOMOYO_PREF_MAX_LEARNING_ENTRY])
                return true;
        if (!domain->flags[TOMOYO_DIF_QUOTA_WARNED]) {
                domain->flags[TOMOYO_DIF_QUOTA_WARNED] = true;
                /* r->granted = false; */
                tomoyo_write_log(r, "%s", tomoyo_dif[TOMOYO_DIF_QUOTA_WARNED]);
#ifndef CONFIG_SECURITY_TOMOYO_INSECURE_BUILTIN_SETTING
                pr_warn("WARNING: Domain '%s' has too many ACLs to hold. Stopped learning mode.\n",
                        domain->domainname->name);
#endif
        }
        return false;
}