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Fix for the recent patch that allows segment offloaded packets.

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We recently added support for segment offloaded packets. It turns out
that this can lead to problems in UDP/ICMP based parsers since I missed
correctly also updating the payloadlength there, and using the capture
length instead when segment offloading is enabled.

Credit to OSS-Fuzz for discovery
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=41391
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=41394
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=41395
(Link to details becomes public 30 days after patch release)
This commit is contained in:
Johanna Amann 2021-11-30 18:24:03 +00:00 • committed by Tim Wojtulewicz
parent 6a5b51eba8
commit 94ee837398
4 changed files with 24 additions and 1 deletions
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4
src/packet_analysis/protocol/icmp/ICMP.cc
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@ -67,6 +67,10 @@ void ICMPAnalyzer::DeliverPacket(Connection* c, double t, bool is_orig, int rema
const u_char* data = pkt->ip_hdr->Payload();
int len = pkt->ip_hdr->PayloadLen();
// If segment offloading or similar is enabled, the payload len will return 0.
// Thus, let's ignore that case.
if ( len == 0 )
len = remaining;
if ( packet_contents && len > 0 )
adapter->PacketContents(data + 8, std::min(len, remaining) - 8);