Description
In the Linux kernel, the following vulnerability has been resolved: tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) When MTU is large, ip6_default_advmss() can return IPV6_MAXPLEN (65535). This is interpreted by TCP as mss_clamp, allowing the MSS to reach 65535. However, 0xFFFF is also used as a magic value GSO_BY_FRAGS in the kernel. If a TCP packet with gso_size=0xFFFF is passed to skb_segment(), it will be mistakenly treated as GSO_BY_FRAGS, leading to a NULL pointer dereference because local TCP packets do not use frag_list. Fix this by returning min(IPV6_MAXPLEN, GSO_BY_FRAGS - 1) (65534) from ip6_default_advmss() when MTU is large. Also update the stale comment in ip6_default_advmss() which suggested that IPV6_MAXPLEN is returned to mean "any MSS".
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
3953c46c3ac7eef31a9935427371c6f54a22f1ba to < 560b33b434e922ef97f9ff23aa2e909ef7aacd5caffected3953c46c3ac7eef31a9935427371c6f54a22f1ba to < 21f69ac1879bb970588d5e7c12a96e6542f7c1a7affected3953c46c3ac7eef31a9935427371c6f54a22f1ba to < c0db3dc2ac323b6c4b76adede3b355a9daa6dea8affected3953c46c3ac7eef31a9935427371c6f54a22f1ba to < 572fff10819dfc359298d1f774839e76a4d96f93affected3953c46c3ac7eef31a9935427371c6f54a22f1ba to < 8e6214a530c03e341dc1b0a846c8f2b716b3551aaffected3953c46c3ac7eef31a9935427371c6f54a22f1ba to < d774cdbda6634a78d0f2baf201ee5a8c57f3bc0eaffected3953c46c3ac7eef31a9935427371c6f54a22f1ba to < a210791f33345aa87187f7d7a9f3b9b7f4a28e6daffected3953c46c3ac7eef31a9935427371c6f54a22f1ba to < 2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22affected
Linux Linux
Default version status: affected
4.8affected0 to < 4.8unaffected5.10.261 to ≤ 5.10.*unaffected5.15.212 to ≤ 5.15.*unaffected6.1.178 to ≤ 6.1.*unaffected6.6.145 to ≤ 6.6.*unaffected6.12.97 to ≤ 6.12.*unaffected6.18.40 to ≤ 6.18.*unaffected7.1.5 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/560b33b434e922ef97f9ff23aa2e909ef7aacd5c ↗
- https://git.kernel.org/stable/c/21f69ac1879bb970588d5e7c12a96e6542f7c1a7 ↗
- https://git.kernel.org/stable/c/c0db3dc2ac323b6c4b76adede3b355a9daa6dea8 ↗
- https://git.kernel.org/stable/c/572fff10819dfc359298d1f774839e76a4d96f93 ↗
- https://git.kernel.org/stable/c/8e6214a530c03e341dc1b0a846c8f2b716b3551a ↗
- https://git.kernel.org/stable/c/d774cdbda6634a78d0f2baf201ee5a8c57f3bc0e ↗
- https://git.kernel.org/stable/c/a210791f33345aa87187f7d7a9f3b9b7f4a28e6d ↗
- https://git.kernel.org/stable/c/2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22 ↗