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TOMOYO: Allow using executable's realpath and symlink's target as con…
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…ditions.

This patch adds support for permission checks using executable file's realpath
upon execve() and symlink's target upon symlink(). Hooks are in the last patch
of this pathset.

Signed-off-by: Tetsuo Handa <[email protected]>
Signed-off-by: James Morris <[email protected]>
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Tetsuo Handa authored and James Morris committed Jul 11, 2011
1 parent 8761afd commit 2ca9bf4
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Showing 5 changed files with 228 additions and 4 deletions.
21 changes: 21 additions & 0 deletions security/tomoyo/audit.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -140,22 +140,43 @@ char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
{
char *buf = 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);
if (!realpath)
goto out;
/* +80 is for " exec={ realpath=\"%s\" }" */
len += strlen(realpath) + 80;
} 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) {
pos += snprintf(buf + pos, len - pos,
" exec={ realpath=\"%s\" }", realpath);
} 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(header);
return buf;
}
Expand Down
66 changes: 66 additions & 0 deletions security/tomoyo/common.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -79,6 +79,8 @@ const char * const tomoyo_condition_keyword[TOMOYO_MAX_CONDITION_KEYWORD] = {
[TOMOYO_MODE_OTHERS_READ] = "others_read",
[TOMOYO_MODE_OTHERS_WRITE] = "others_write",
[TOMOYO_MODE_OTHERS_EXECUTE] = "others_execute",
[TOMOYO_EXEC_REALPATH] = "exec.realpath",
[TOMOYO_SYMLINK_TARGET] = "symlink.target",
[TOMOYO_PATH1_UID] = "path1.uid",
[TOMOYO_PATH1_GID] = "path1.gid",
[TOMOYO_PATH1_INO] = "path1.ino",
Expand Down Expand Up @@ -352,6 +354,27 @@ static void tomoyo_print_name_union(struct tomoyo_io_buffer *head,
}
}

/**
* tomoyo_print_name_union_quoted - Print a tomoyo_name_union with a quote.
*
* @head: Pointer to "struct tomoyo_io_buffer".
* @ptr: Pointer to "struct tomoyo_name_union".
*
* Returns nothing.
*/
static void tomoyo_print_name_union_quoted(struct tomoyo_io_buffer *head,
const struct tomoyo_name_union *ptr)
{
if (ptr->group) {
tomoyo_set_string(head, "@");
tomoyo_set_string(head, ptr->group->group_name->name);
} else {
tomoyo_set_string(head, "\"");
tomoyo_set_string(head, ptr->filename->name);
tomoyo_set_string(head, "\"");
}
}

/**
* tomoyo_print_number_union_nospace - Print a tomoyo_number_union without a space.
*
Expand Down Expand Up @@ -1101,6 +1124,9 @@ static bool tomoyo_print_condition(struct tomoyo_io_buffer *head,
(typeof(condp)) (cond + 1);
const struct tomoyo_number_union *numbers_p =
(typeof(numbers_p)) (condp + condc);
const struct tomoyo_name_union *names_p =
(typeof(names_p))
(numbers_p + cond->numbers_count);
u16 skip;
for (skip = 0; skip < head->r.cond_index; skip++) {
const u8 left = condp->left;
Expand All @@ -1112,6 +1138,9 @@ static bool tomoyo_print_condition(struct tomoyo_io_buffer *head,
break;
}
switch (right) {
case TOMOYO_NAME_UNION:
names_p++;
break;
case TOMOYO_NUMBER_UNION:
numbers_p++;
break;
Expand All @@ -1138,6 +1167,10 @@ static bool tomoyo_print_condition(struct tomoyo_io_buffer *head,
}
tomoyo_set_string(head, match ? "=" : "!=");
switch (right) {
case TOMOYO_NAME_UNION:
tomoyo_print_name_union_quoted
(head, names_p++);
break;
case TOMOYO_NUMBER_UNION:
tomoyo_print_number_union_nospace
(head, numbers_p++);
Expand Down Expand Up @@ -1665,6 +1698,22 @@ static DEFINE_SPINLOCK(tomoyo_query_list_lock);
*/
static atomic_t tomoyo_query_observers = ATOMIC_INIT(0);

/**
* tomoyo_truncate - Truncate a line.
*
* @str: String to truncate.
*
* Returns length of truncated @str.
*/
static int tomoyo_truncate(char *str)
{
char *start = str;
while (*(unsigned char *) str > (unsigned char) ' ')
str++;
*str = '\0';
return strlen(start) + 1;
}

/**
* tomoyo_add_entry - Add an ACL to current thread's domain. Used by learning mode.
*
Expand All @@ -1676,6 +1725,8 @@ static atomic_t tomoyo_query_observers = ATOMIC_INIT(0);
static void tomoyo_add_entry(struct tomoyo_domain_info *domain, char *header)
{
char *buffer;
char *realpath = NULL;
char *symlink = NULL;
char *cp = strchr(header, '\n');
int len;
if (!cp)
Expand All @@ -1685,10 +1736,25 @@ static void tomoyo_add_entry(struct tomoyo_domain_info *domain, char *header)
return;
*cp++ = '\0';
len = strlen(cp) + 1;
/* strstr() will return NULL if ordering is wrong. */
if (*cp == 'f') {
realpath = strstr(header, " exec={ realpath=\"");
if (realpath) {
realpath += 8;
len += tomoyo_truncate(realpath) + 6;
}
symlink = strstr(header, " symlink.target=\"");
if (symlink)
len += tomoyo_truncate(symlink + 1) + 1;
}
buffer = kmalloc(len, GFP_NOFS);
if (!buffer)
return;
snprintf(buffer, len - 1, "%s", cp);
if (realpath)
tomoyo_addprintf(buffer, len, " exec.%s", realpath);
if (symlink)
tomoyo_addprintf(buffer, len, "%s", symlink);
tomoyo_normalize_line(buffer);
if (!tomoyo_write_domain2(domain->ns, &domain->acl_info_list, buffer,
false))
Expand Down
24 changes: 24 additions & 0 deletions security/tomoyo/common.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,8 @@ enum tomoyo_conditions_index {
TOMOYO_MODE_OTHERS_READ, /* S_IROTH */
TOMOYO_MODE_OTHERS_WRITE, /* S_IWOTH */
TOMOYO_MODE_OTHERS_EXECUTE, /* S_IXOTH */
TOMOYO_EXEC_REALPATH,
TOMOYO_SYMLINK_TARGET,
TOMOYO_PATH1_UID,
TOMOYO_PATH1_GID,
TOMOYO_PATH1_INO,
Expand Down Expand Up @@ -101,6 +103,7 @@ enum tomoyo_conditions_index {
TOMOYO_PATH2_PARENT_PERM,
TOMOYO_MAX_CONDITION_KEYWORD,
TOMOYO_NUMBER_UNION,
TOMOYO_NAME_UNION,
};


Expand Down Expand Up @@ -351,6 +354,11 @@ struct tomoyo_request_info {
* NULL if not dealing files.
*/
struct tomoyo_obj_info *obj;
/*
* For holding parameters specific to execve() request.
* NULL if not dealing do_execve().
*/
struct tomoyo_execve *ee;
struct tomoyo_domain_info *domain;
/* For holding parameters. */
union {
Expand Down Expand Up @@ -476,6 +484,20 @@ struct tomoyo_obj_info {
* parent directory.
*/
struct tomoyo_mini_stat stat[TOMOYO_MAX_PATH_STAT];
/*
* Content of symbolic link to be created. NULL for operations other
* than symlink().
*/
struct tomoyo_path_info *symlink_target;
};

/* Structure for execve() operation. */
struct tomoyo_execve {
struct tomoyo_request_info r;
struct tomoyo_obj_info obj;
struct linux_binprm *bprm;
/* For temporary use. */
char *tmp; /* Size is TOMOYO_EXEC_TMPSIZE bytes */
};

/* Structure for entries which follows "struct tomoyo_condition". */
Expand All @@ -494,9 +516,11 @@ struct tomoyo_condition {
u32 size; /* Memory size allocated for this entry. */
u16 condc; /* Number of conditions in this struct. */
u16 numbers_count; /* Number of "struct tomoyo_number_union values". */
u16 names_count; /* Number of "struct tomoyo_name_union names". */
/*
* struct tomoyo_condition_element condition[condc];
* struct tomoyo_number_union values[numbers_count];
* struct tomoyo_name_union names[names_count];
*/
};

Expand Down
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