Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry New test case fails unexpectedly when avx2 matching functions are used. The test first loads a ranomly generated pipapo set with 'ipv4 . port' key, i.e. nft -f foo. This works. Then, it reloads the set after a flush: (echo flush set t s; cat foo) | nft -f - This is expected to work, because its the same set after all and it was already loaded once. But with avx2, this fails: nft reports a clashing element. The reported clash is of following form: We successfully re-inserted a . b c . d Then we try to insert a . d avx2 finds the already existing a . d, which (due to 'flush set') is marked as invalid in the new generation. It skips the element and moves to next. Due to incorrect masking, the skip-step finds the next matching element *only considering the first field*, i.e. we return the already reinserted "a . b", even though the last field is different and the entry should not have been matched. No such error is reported for the generic c implementation (no avx2) or when the last field has to use the 'nft_pipapo_avx2_lookup_slow' fallback. Bisection points to 7711f4bb4b36 ("netfilter: nft_set_pipapo: fix range overlap detection") but that fix merely uncovers this bug. Before this commit, the wrong element is returned, but erronously reported as a full, identical duplicate. The root-cause is too early return in the avx2 match functions. When we process the last field, we should continue to process data until the entire input size has been consumed to make sure no stale bits remain in the map.

Affected Products 9

References 8

• git.kernel.org https://git.kernel.org/stable/c/07de44424bb7f17ef9357e8535df96d9e97c40cb
  Patch
• git.kernel.org https://git.kernel.org/stable/c/0abbc43f71d99baadeeba6fa3fe1c80b676f57ed
  Patch
• git.kernel.org https://git.kernel.org/stable/c/1c43f0dd8691ddf8884793b481ddc7511cf593c3
• git.kernel.org https://git.kernel.org/stable/c/3d53f9aafd469ae1ea27051e00f5b96ca1b55d52
  Patch
• git.kernel.org https://git.kernel.org/stable/c/c7babe2f28b507e17f28e9f753b7caec72d4857f
• git.kernel.org https://git.kernel.org/stable/c/d3c0037ffe1273fa1961e779ff6906234d6cf53c
  Patch
• git.kernel.org https://git.kernel.org/stable/c/f8c39983fc9c1a978c82e6f2df7bfba8a8561587
• git.kernel.org https://git.kernel.org/stable/c/fa4f1f52528c73989d820f32bfca06bec5afeece
  Patch

Remediation

• git.kernel.org https://git.kernel.org/stable/c/07de44424bb7f17ef9357e8535df96d9e97c40cb
  Patch
• git.kernel.org https://git.kernel.org/stable/c/0abbc43f71d99baadeeba6fa3fe1c80b676f57ed
  Patch
• git.kernel.org https://git.kernel.org/stable/c/3d53f9aafd469ae1ea27051e00f5b96ca1b55d52
  Patch
• git.kernel.org https://git.kernel.org/stable/c/d3c0037ffe1273fa1961e779ff6906234d6cf53c
  Patch
• git.kernel.org https://git.kernel.org/stable/c/fa4f1f52528c73989d820f32bfca06bec5afeece
  Patch