stream: improve 3whs completed by ACK with data #11824
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If the ACK packet completing the 3whs is received, the stream engine will transition to "established". However, the packet itself will not be tagged as "established". This will only happen for the next packet after the 3whs, so that `flow:established` only matches after the 3whs. It is possible that the ACK packet completing the 3whs was lost. Since the ACK packets themselves are not acknowledged, there will be no retransmission of them. Instead, the next packet can have the expected ACK flag as well as data. This case was mishandled in a subtle way. The stream engine state transition was done correctly, as well as the data handling and app-layer updates. However, the packet itself was not tagged as "established", which meant that `flow:established` would not yet match. This patch detects this case and tags the packet as established if ACK with data is received that completes the 3whs. Bug: OISF#7264.
Codecov ReportAll modified and coverable lines are covered by tests ✅
Additional details and impacted files@@ Coverage Diff @@
## master #11824 +/- ##
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Coverage 82.58% 82.59%
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Files 914 914
Lines 249500 249502 +2
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+ Hits 206045 206070 +25
+ Misses 43455 43432 -23
Flags with carried forward coverage won't be shown. Click here to find out more. |
jufajardini
approved these changes
Sep 23, 2024
jasonish
approved these changes
Sep 23, 2024
|
WARNING:
Pipeline 22785 |
Merged
|
Merged in #11829, thanks! |
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If the ACK packet completing the 3whs is received, the stream engine will transition to "established". However, the packet itself will not be tagged as "established". This will only happen for the next packet after the 3whs, so that
flow:establishedonly matches after the 3whs.It is possible that the ACK packet completing the 3whs was lost. Since the ACK packets themselves are not acknowledged, there will be no retransmission of them. Instead, the next packet can have the expected ACK flag as well as data.
This case was mishandled in a subtle way. The stream engine state transition was done correctly, as well as the data handling and app-layer updates. However, the packet itself was not tagged as "established", which meant that
flow:establishedwould not yet match.This patch detects this case and tags the packet as established if ACK with data is received that completes the 3whs.
Bug: #7264.
replaces #11821
SV_BRANCH=OISF/suricata-verify#2051