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| author | Prasad J Pandit <pjp@fedoraproject.org> | 2016-03-02 17:29:58 +0530 |
|---|---|---|
| committer | Jason Wang <jasowang@redhat.com> | 2016-03-08 15:34:18 +0800 |
| commit | 362786f14a753d8a5256ef97d7c10ed576d6572b (patch) | |
| tree | df46cf293e0e12fdd91068e3aa60b228a8ab061d /net | |
| parent | f1b2bc601af5037f0af6d55575e619b912e348b5 (diff) | |
| download | qemu-362786f14a753d8a5256ef97d7c10ed576d6572b.zip qemu-362786f14a753d8a5256ef97d7c10ed576d6572b.tar.gz qemu-362786f14a753d8a5256ef97d7c10ed576d6572b.tar.bz2 | |
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')
| -rw-r--r-- | net/checksum.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/net/checksum.c b/net/checksum.c index b5016ab..d0fa424 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; |