diff options
| author | Alexander Duyck <alexander.h.duyck@redhat.com> | 2015-03-10 14:39:34 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-03-10 18:36:56 -0400 |
| commit | ddb4b9a1328ea89733133e86cf1972d23891abfc (patch) | |
| tree | 39e6b01f93a37c97fa6721ff7fa0976cd44a0555 /net/ipv4/fib_trie.c | |
| parent | 416377ea392823e8ea1f8a10477e7d08a9bb715e (diff) | |
| download | lwn-ddb4b9a1328ea89733133e86cf1972d23891abfc.tar.gz lwn-ddb4b9a1328ea89733133e86cf1972d23891abfc.zip | |
fib_trie: Address possible NULL pointer dereference in resize
If the inflate call failed it would return NULL. As a result tp would be
set to NULL and cause use to trigger a NULL pointer dereference in
should_halve if the inflate failed on the first attempt.
In order to prevent this we should decrement max_work before we actually
attempt to inflate as this will force us to exit before attempting to halve
a node we should have inflated. In order to keep things symmetric between
inflate and halve I went ahead and also moved the decrement of max_work for
the halve case as well so we take care of that before we actually attempt
to halve the tnode.
Fixes: 88bae714 ("fib_trie: Add key vector to root, return parent key_vector in resize")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/fib_trie.c')
| -rw-r--r-- | net/ipv4/fib_trie.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index 44cab1d41463..83290beaf7cf 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -830,7 +830,7 @@ static struct key_vector *resize(struct trie *t, struct key_vector *tn) /* Double as long as the resulting node has a number of * nonempty nodes that are above the threshold. */ - while (should_inflate(tp, tn) && max_work) { + while (should_inflate(tp, tn) && max_work--) { tp = inflate(t, tn); if (!tp) { #ifdef CONFIG_IP_FIB_TRIE_STATS @@ -839,7 +839,6 @@ static struct key_vector *resize(struct trie *t, struct key_vector *tn) break; } - max_work--; tn = get_child(tp, cindex); } @@ -850,7 +849,7 @@ static struct key_vector *resize(struct trie *t, struct key_vector *tn) /* Halve as long as the number of empty children in this * node is above threshold. */ - while (should_halve(tp, tn) && max_work) { + while (should_halve(tp, tn) && max_work--) { tp = halve(t, tn); if (!tp) { #ifdef CONFIG_IP_FIB_TRIE_STATS @@ -859,7 +858,6 @@ static struct key_vector *resize(struct trie *t, struct key_vector *tn) break; } - max_work--; tn = get_child(tp, cindex); } |