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Commit a3c54931 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Linus Torvalds
Browse files

auditsc: audit_krule mask accesses need bounds checking 



Fixes an easy DoS and possible information disclosure.

This does nothing about the broken state of x32 auditing.

eparis: If the admin has enabled auditd and has specifically loaded
audit rules.  This bug has been around since before git.  Wow...

Cc: stable@vger.kernel.org
Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 64b2d1fb

kernel/auditsc.c

+18 −9
Original line number Diff line number Diff line
@@ -728,6 +728,22 @@ static enum audit_state audit_filter_task(struct task_struct *tsk, char **key) 
	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
@@ -745,11 +761,8 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk, 


	rcu_read_lock();

	if (!list_empty(list)) {

		int word = AUDIT_WORD(ctx->major);

		int bit  = AUDIT_BIT(ctx->major);



		list_for_each_entry_rcu(e, list, list) {

			if ((e->rule.mask[word] & bit) == bit &&

			if (audit_in_mask(&e->rule, ctx->major) &&

			    audit_filter_rules(tsk, &e->rule, ctx, NULL,

					       &state, false)) {

				rcu_read_unlock();
@@ -769,20 +782,16 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk, 
static int audit_filter_inode_name(struct task_struct *tsk,

				   struct audit_names *n,

				   struct audit_context *ctx) {

	int word, bit;

	int h = audit_hash_ino((u32)n->ino);

	struct list_head *list = &audit_inode_hash[h];

	struct audit_entry *e;

	enum audit_state state;



	word = AUDIT_WORD(ctx->major);

	bit  = AUDIT_BIT(ctx->major);



	if (list_empty(list))

		return 0;



	list_for_each_entry_rcu(e, list, list) {

		if ((e->rule.mask[word] & bit) == bit &&

		if (audit_in_mask(&e->rule, ctx->major) &&

		    audit_filter_rules(tsk, &e->rule, ctx, n, &state, false)) {

			ctx->current_state = state;

			return 1;