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

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
...@@ -728,6 +728,22 @@ static enum audit_state audit_filter_task(struct task_struct *tsk, char **key) ...@@ -728,6 +728,22 @@ static enum audit_state audit_filter_task(struct task_struct *tsk, char **key)
return AUDIT_BUILD_CONTEXT; 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 /* 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 * 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 * 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, ...@@ -745,11 +761,8 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk,
rcu_read_lock(); rcu_read_lock();
if (!list_empty(list)) { if (!list_empty(list)) {
int word = AUDIT_WORD(ctx->major);
int bit = AUDIT_BIT(ctx->major);
list_for_each_entry_rcu(e, list, list) { 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, audit_filter_rules(tsk, &e->rule, ctx, NULL,
&state, false)) { &state, false)) {
rcu_read_unlock(); rcu_read_unlock();
...@@ -769,20 +782,16 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk, ...@@ -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, static int audit_filter_inode_name(struct task_struct *tsk,
struct audit_names *n, struct audit_names *n,
struct audit_context *ctx) { struct audit_context *ctx) {
int word, bit;
int h = audit_hash_ino((u32)n->ino); int h = audit_hash_ino((u32)n->ino);
struct list_head *list = &audit_inode_hash[h]; struct list_head *list = &audit_inode_hash[h];
struct audit_entry *e; struct audit_entry *e;
enum audit_state state; enum audit_state state;
word = AUDIT_WORD(ctx->major);
bit = AUDIT_BIT(ctx->major);
if (list_empty(list)) if (list_empty(list))
return 0; return 0;
list_for_each_entry_rcu(e, list, list) { 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)) { audit_filter_rules(tsk, &e->rule, ctx, n, &state, false)) {
ctx->current_state = state; ctx->current_state = state;
return 1; return 1;
......
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