From 6f5d51148921c242680a7a1d9913384a30ab3cbe Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 19 Dec 2009 15:59:45 +0000 Subject: [PATCH] fix braindamage in audit_tree.c untag_chunk() ... aka "Al had badly fscked up when writing that thing and nobody noticed until Eric had fixed leaks that used to mask the breakage". The function essentially creates a copy of old array sans one element and replaces the references to elements of original (they are on cyclic lists) with those to corresponding elements of new one. After that the old one is fair game for freeing. First of all, there's a dumb braino: when we get to list_replace_init we use indices for wrong arrays - position in new one with the old array and vice versa. Another bug is more subtle - termination condition is wrong if the element to be excluded happens to be the last one. We shouldn't go until we fill the new array, we should go until we'd finished the old one. Otherwise the element we are trying to kill will remain on the cyclic lists... That crap used to be masked by several leaks, so it was not quite trivial to hit. Eric had fixed some of those leaks a while ago and the shit had hit the fan... Signed-off-by: Al Viro Signed-off-by: Linus Torvalds --- kernel/audit_tree.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c index 2451dc6f328..b36aa9651ba 100644 --- a/kernel/audit_tree.c +++ b/kernel/audit_tree.c @@ -277,7 +277,7 @@ static void untag_chunk(struct node *p) owner->root = NULL; } - for (i = j = 0; i < size; i++, j++) { + for (i = j = 0; j <= size; i++, j++) { struct audit_tree *s; if (&chunk->owners[j] == p) { list_del_init(&p->list); @@ -290,7 +290,7 @@ static void untag_chunk(struct node *p) if (!s) /* result of earlier fallback */ continue; get_tree(s); - list_replace_init(&chunk->owners[i].list, &new->owners[j].list); + list_replace_init(&chunk->owners[j].list, &new->owners[i].list); } list_replace_rcu(&chunk->hash, &new->hash);