Messages in this thread Patch in this message | | | Date | Sat, 14 Jun 2014 21:12:58 +0200 | From | Willy Tarreau <> | Subject | [ 8/9] auditsc: audit_krule mask accesses need bounds checking |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
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From: Andy Lutomirski <luto@amacapital.net>
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: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit a3c54931199565930d6d84f4c3456f6440aefd41) [wt: no audit_filter_inode_name(), applied to audit_filter_inodes() instead] Signed-off-by: Willy Tarreau <w@1wt.eu> --- kernel/auditsc.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 267e484..b6998ef 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -680,6 +680,22 @@ 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 @@ -697,11 +713,8 @@ 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)) { rcu_read_unlock(); @@ -730,8 +743,6 @@ void audit_filter_inodes(struct task_struct *tsk, struct audit_context *ctx) rcu_read_lock(); for (i = 0; i < ctx->name_count; i++) { - int word = AUDIT_WORD(ctx->major); - int bit = AUDIT_BIT(ctx->major); struct audit_names *n = &ctx->names[i]; int h = audit_hash_ino((u32)n->ino); struct list_head *list = &audit_inode_hash[h]; @@ -740,7 +751,7 @@ void audit_filter_inodes(struct task_struct *tsk, struct audit_context *ctx) continue; 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)) { rcu_read_unlock(); ctx->current_state = state; -- 1.7.12.2.21.g234cd45.dirty
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