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authorAlexander Duyck <alexander.h.duyck@redhat.com>2015-03-10 14:39:34 -0700
committerDavid S. Miller <davem@davemloft.net>2015-03-10 18:36:56 -0400
commitddb4b9a1328ea89733133e86cf1972d23891abfc (patch)
tree39e6b01f93a37c97fa6721ff7fa0976cd44a0555 /net/ipv4/fib_trie.c
parent416377ea392823e8ea1f8a10477e7d08a9bb715e (diff)
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.c6
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);
}