Description
In the Linux kernel, the following vulnerability has been resolved: 6lowpan: fix NHC entry use-after-free on error path lowpan_nhc_do_uncompression() looks up an NHC descriptor while holding lowpan_nhc_lock. If the descriptor has no uncompress callback, the error path drops the lock before printing nhc->name. lowpan_nhc_del() removes descriptors under the same lock and then relies on synchronize_net() before the owning module can be unloaded. That only waits for net RX RCU readers. lowpan_header_decompress() is also exported and can be reached from callers that are not necessarily covered by the net core RX critical section, for example the Bluetooth 6LoWPAN L2CAP receive path. This leaves a race where one task drops lowpan_nhc_lock in the error path, another task unregisters and frees the matching descriptor after synchronize_net() returns, and the first task then dereferences nhc->name for the warning. With the post-unlock window widened, KASAN reports: BUG: KASAN: slab-use-after-free in lowpan_nhc_do_uncompression+0x1f4/0x220 Read of size 8 lowpan_nhc_do_uncompression lowpan_header_decompress Fix this by printing the warning before dropping lowpan_nhc_lock, so the descriptor name is read while unregister is still excluded. The malformed packet is still rejected with -ENOTSUPP.
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
92aa7c65d295f3cbb96904afe335f683e55584b8 to < 9c2f5c0829a8c8b904dae36be6d8056b719ac605affected92aa7c65d295f3cbb96904afe335f683e55584b8 to < 80b5c8779acee0550845394fb3e5176a398aa24caffected92aa7c65d295f3cbb96904afe335f683e55584b8 to < cc27aea4d454abfb385ee2c9499c78b96db9b728affected92aa7c65d295f3cbb96904afe335f683e55584b8 to < a8e3a94711134e898c6021a6b77374efa91b3639affected92aa7c65d295f3cbb96904afe335f683e55584b8 to < 593b78bb3c7ef0c6e9ae6fdf5afa80a5f7573168affected92aa7c65d295f3cbb96904afe335f683e55584b8 to < 0beccbcf50de125be5520d0ffc59af4bb8655482affected92aa7c65d295f3cbb96904afe335f683e55584b8 to < b713aa0cc344f10f7a9928a230b5f5e780d04078affected92aa7c65d295f3cbb96904afe335f683e55584b8 to < 1720db928e5a58ca7d75ac1d514c3b73fd7061a7affected
Linux Linux
Default version status: affected
4.1affected0 to < 4.1unaffected5.10.261 to ≤ 5.10.*unaffected5.15.212 to ≤ 5.15.*unaffected6.1.178 to ≤ 6.1.*unaffected6.6.145 to ≤ 6.6.*unaffected6.12.96 to ≤ 6.12.*unaffected6.18.39 to ≤ 6.18.*unaffected7.1.4 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/9c2f5c0829a8c8b904dae36be6d8056b719ac605 ↗
- https://git.kernel.org/stable/c/80b5c8779acee0550845394fb3e5176a398aa24c ↗
- https://git.kernel.org/stable/c/cc27aea4d454abfb385ee2c9499c78b96db9b728 ↗
- https://git.kernel.org/stable/c/a8e3a94711134e898c6021a6b77374efa91b3639 ↗
- https://git.kernel.org/stable/c/593b78bb3c7ef0c6e9ae6fdf5afa80a5f7573168 ↗
- https://git.kernel.org/stable/c/0beccbcf50de125be5520d0ffc59af4bb8655482 ↗
- https://git.kernel.org/stable/c/b713aa0cc344f10f7a9928a230b5f5e780d04078 ↗
- https://git.kernel.org/stable/c/1720db928e5a58ca7d75ac1d514c3b73fd7061a7 ↗