crypto: algif_skcipher - force synchronous processing on trees without ctx->state

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74578
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-16 09:16:21 UTC
Updated2026-08-16 09:16:21 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: crypto: algif_skcipher - force synchronous processing on trees without ctx->state The AIO/async path in skcipher_recvmsg() passes the socket-wide ctx->iv directly into the skcipher request. After io_submit() the socket lock is dropped and the request is processed asynchronously, so a concurrent sendmsg(ALG_SET_IV) can overwrite ctx->iv and make the in-flight request run under an attacker-controlled IV. For CTR/stream modes this is IV/keystream reuse and lets an unprivileged user recover the plaintext of a concurrent operation. Snapshotting ctx->iv into per-request storage for the async path is not sufficient. For ciphers with statesize == 0 - which includes cbc and ctr - the MSG_MORE inter-chunk IV chaining is carried solely by the in-place req->iv writeback, which a snapshot redirects into per-request memory that af_alg_free_resources() releases on completion, silently producing wrong output. Writing the IV back from the completion callback instead is not possible either: that would require lock_sock() there, but the callback can run in softirq/atomic context, so it must not sleep. Make the operation synchronous instead, which removes both the IV race and any writeback race. This is equivalent to the upstream resolution, commit fcc77d33a34c ("net: Remove support for AIO on sockets"), which removed the AIO socket path across net/ entirely and so produces the same end state for this file. This patch deviates from that commit deliberately: rather than removing AIO socket support tree-wide, which would be far too invasive for stable, it removes only the AIO branch in crypto/algif_skcipher.c. io_submit() now completes synchronously; AF_ALG async is rarely used in practice. The -EIOCBQUEUED check in skcipher_recvmsg() is now dead but harmless, and is left alone to keep the fix minimal. Tested on 6.6.y: attacker IV injection dropped from 2296/200000 to 0/200000 after the change; MSG_MORE chunked CTR output bit-identical to single-shot.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected e870456d8e7c8d57c059ea479b5aadbb55ff4c3a bf09b0be8e851f050e98da702d247c14d81b591a git Not specified
CNA Linux Linux affected e870456d8e7c8d57c059ea479b5aadbb55ff4c3a 73dd3bf704ca6c20639de70c08e9a10bee904a95 git Not specified
CNA Linux Linux affected e870456d8e7c8d57c059ea479b5aadbb55ff4c3a f1a87ca0843d74482402a206ea2dfb315ee9acbd git Not specified
CNA Linux Linux affected e870456d8e7c8d57c059ea479b5aadbb55ff4c3a 7b91e51d0eb7cbb07f7f086f9176bd93dbbc85dd git Not specified
CNA Linux Linux affected e870456d8e7c8d57c059ea479b5aadbb55ff4c3a 60eafc7b08c6689ea3ad39eff8d97aefc8a087c7 git Not specified
CNA Linux Linux affected e870456d8e7c8d57c059ea479b5aadbb55ff4c3a d7860b682da55433b5da0591b0e4c1982ecd2689 git Not specified
CNA Linux Linux affected e870456d8e7c8d57c059ea479b5aadbb55ff4c3a b05defc41b27c7d0c05c45f67bf5b91c28f93669 git Not specified
CNA Linux Linux affected e870456d8e7c8d57c059ea479b5aadbb55ff4c3a fcc77d33a34cf271702e8daafb6c593e4626776d git Not specified
CNA Linux Linux affected 4.14 Not specified
CNA Linux Linux unaffected 4.14 semver Not specified
CNA Linux Linux unaffected 5.10.261 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.212 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/73dd3bf704ca6c20639de70c08e9a10bee904a95 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/fcc77d33a34cf271702e8daafb6c593e4626776d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d7860b682da55433b5da0591b0e4c1982ecd2689 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b05defc41b27c7d0c05c45f67bf5b91c28f93669 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f1a87ca0843d74482402a206ea2dfb315ee9acbd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/60eafc7b08c6689ea3ad39eff8d97aefc8a087c7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7b91e51d0eb7cbb07f7f086f9176bd93dbbc85dd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bf09b0be8e851f050e98da702d247c14d81b591a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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