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authorAndy Lutomirski <luto@amacapital.net>2014-05-28 23:09:58 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-16 13:45:46 -0700
commit39da9a416814e556060bab8569293b8f3d889765 (patch)
tree47e6e9dc9b64c873e31bd67dfe4d9ecdfb81ea98
parent35a2bae84d5bc0a6609134b51053f78d235940c2 (diff)
downloadlinux-linaro-stable-39da9a416814e556060bab8569293b8f3d889765.tar.gz
auditsc: audit_krule mask accesses need bounds checking
commit a3c54931199565930d6d84f4c3456f6440aefd41 upstream. 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... Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/auditsc.c27
1 files changed, 18 insertions, 9 deletions
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index af1de0f34eae..549071209258 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -868,6 +868,22 @@ 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
@@ -885,11 +901,8 @@ 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();
@@ -909,20 +922,16 @@ 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;