net/sched: cls_api: fix teardown of an adopted proto on insert-race loss

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-90248
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 17:17:20 UTC
Updated2026-09-17 17:17:20 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: fix teardown of an adopted proto on insert-race loss In tc_new_tfilter() the create branch sets tp_created = 1 before calling tcf_chain_tp_insert_unique(). When the caller loses the race (another request inserted a proto at the same chain/prio first), insert_unique() destroys the caller's own tp_new and returns the winner's proto with an extra reference. tp_created was never cleared, so the loser's errout path treated the winner's live proto as its own and called tcf_chain_tp_delete_empty() on it, silently unlinking an active classifier that the winning request already advertised via RTM_NEWTFILTER. Track the outcome of the insert step in a single tri-state variable so each errout path reacts correctly: - TP_NOT_CREATED: no proto created; pursue the old path. - TP_CREATED: proto inserted successfully; same code path as before. - TP_NOT_OWNED: New - lost the insert race; tp is another request's proto (chain ref already released by tp_new's destroy) Both errout reactions are single expressions derived from the state. This fix is motivated by the Sashiko's automated review of Patch (net/sched: cls_api: Always acquire rtnl_lock when destroying locked classifiers) [1][2]. The review identified the silent-unlink behaviour of an adopted proto's teardown when a request loses the tcf_chain_tp_insert_unique() race. [1] https://sashiko.dev/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com [2] https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 8b64678e0af8f4d62a40149baedebe78503a5255 a68e664ddf16ecae6d769d6a2eb356f8abab75c9 git Not specified
CNA Linux Linux affected 8b64678e0af8f4d62a40149baedebe78503a5255 df02b6dc136af45e92ee4c86f4aa6c9a60790b1e git Not specified
CNA Linux Linux affected 8b64678e0af8f4d62a40149baedebe78503a5255 bee2208276c8e0e40a249ffdcf6e5434a79a847c git Not specified
CNA Linux Linux affected 8b64678e0af8f4d62a40149baedebe78503a5255 219c87aeefdcc8c1caf28cc99e9b361ce7393d3a git Not specified
CNA Linux Linux affected 8b64678e0af8f4d62a40149baedebe78503a5255 bbe2fd6d77df630356185406a97317f6aa6a92cf git Not specified
CNA Linux Linux affected 8b64678e0af8f4d62a40149baedebe78503a5255 dc8b33b819cb02a75936940c120aa669ad89942d git Not specified
CNA Linux Linux affected 8b64678e0af8f4d62a40149baedebe78503a5255 d4e359b3608a0e184bbe8d61a5c3b50d0831c44a git Not specified
CNA Linux Linux affected 5.1 Not specified
CNA Linux Linux unaffected 5.1 semver Not specified
CNA Linux Linux unaffected 5.15.221 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.188 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.157 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.52 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.6 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/d4e359b3608a0e184bbe8d61a5c3b50d0831c44a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/dc8b33b819cb02a75936940c120aa669ad89942d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bbe2fd6d77df630356185406a97317f6aa6a92cf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bee2208276c8e0e40a249ffdcf6e5434a79a847c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/219c87aeefdcc8c1caf28cc99e9b361ce7393d3a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/df02b6dc136af45e92ee4c86f4aa6c9a60790b1e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a68e664ddf16ecae6d769d6a2eb356f8abab75c9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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