mptcp: fastopen: only mark MPTFO subflows with SYN data
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.6.153, 6.12.105, 6.18.46, 7.1.10
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
In the Linux kernel, the following vulnerability has been resolved: mptcp: fastopen: only mark MPTFO subflows with SYN data Passive TCP Fast Open accepts a valid-cookie SYN even when it carries no data. In that case the child socket's receive queue is intentionally left empty. mptcp_fastopen_subflow_synack_set_params() set is_mptfo before checking for queued SYN data. That made data-less TFO SYNs hit a WARN and, if the warning was non-fatal, left stale MPTFO state behind. The stale flag could later trigger a state-confusion bug in check_fully_established(). Only mark the subflow as MPTFO after confirming that an SKB was queued. Return quietly when the receive queue is empty. Note that mptcp_subflow_context's is_mptfo field is now not just about subflows where the TFO was present, but about MPTFO subflow that consumed SYN data. Only having a valid cookie but not carrying data is not really "doing TFO".
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- Linux Linux
From 36b122baf6a8bd46b4a591f12f4ed17b22257408 · fixed in f75f174edc865738522e514d042cf5627f084859; From 36b122baf6a8bd46b4a591f12f4ed17b22257408 · fixed in fca7e444c04689fe4cc6b56f2725f804a4bb1ef9; From 36b122baf6a8bd46b4a591f12f4ed17b22257408 · fixed in 75e564b2ced1cc3d9a8904c7d2d2bb448fffb8b5; From 36b122baf6a8bd46b4a591f12f4ed17b22257408 · fixed in 72b4a0c51a4b550d40301d60a366b429b8c8e78d; From 36b122baf6a8bd46b4a591f12f4ed17b22257408 · fixed in e00b63056fb4f261455b3e5df5268a1f8ce47a87
- Linux Linux
6.2
- KernelLinux
From 6.2.0 · fixed in 6.6.153; From 6.7.0 · fixed in 6.12.105; From 6.13.0 · fixed in 6.18.46; From 6.19.0 · fixed in 7.1.10