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authorPrasad J Pandit <pjp@fedoraproject.org>2016-03-02 17:29:58 +0530
committerJason Wang <jasowang@redhat.com>2016-03-08 15:34:18 +0800
commit362786f14a753d8a5256ef97d7c10ed576d6572b (patch)
treedf46cf293e0e12fdd91068e3aa60b228a8ab061d /net/checksum.c
parentf1b2bc601af5037f0af6d55575e619b912e348b5 (diff)
net: check packet payload length
While computing IP checksum, 'net_checksum_calculate' reads payload length from the packet. It could exceed the given 'data' buffer size. Add a check to avoid it. Reported-by: Liu Ling <liuling-it@360.cn> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org> Signed-off-by: Jason Wang <jasowang@redhat.com>
Diffstat (limited to 'net/checksum.c')
-rw-r--r--net/checksum.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/net/checksum.c b/net/checksum.c
index b5016ab40c..d0fa424cc1 100644
--- a/net/checksum.c
+++ b/net/checksum.c
@@ -60,6 +60,11 @@ void net_checksum_calculate(uint8_t *data, int length)
int hlen, plen, proto, csum_offset;
uint16_t csum;
+ /* Ensure data has complete L2 & L3 headers. */
+ if (length < 14 + 20) {
+ return;
+ }
+
if ((data[14] & 0xf0) != 0x40)
return; /* not IPv4 */
hlen = (data[14] & 0x0f) * 4;
@@ -77,8 +82,9 @@ void net_checksum_calculate(uint8_t *data, int length)
return;
}
- if (plen < csum_offset+2)
- return;
+ if (plen < csum_offset + 2 || 14 + hlen + plen > length) {
+ return;
+ }
data[14+hlen+csum_offset] = 0;
data[14+hlen+csum_offset+1] = 0;