rxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg

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Summary

CVECVE-2026-64026
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 16:17:42 UTC
Updated2026-07-19 16:17:42 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg This improves the fix for CVE-2026-43500. Fix the pagecache corruption from in-place decryption of a DATA packet transmitted locally by splice() by getting rid of the packet sharing in the I/O thread and unconditionally extracting the packet content into a bounce buffer in which the buffer is decrypted. recvmsg() (or the kernel equivalent) then copies the data from the bounce buffer to the destination buffer. The sk_buff then remains unmodified. This has an additional advantage in that the packet is then arranged in the buffer with the correct alignment required for the crypto algorithms to process directly. The performance of the crypto does seem to be a little faster and, surprisingly, the unencrypted performance doesn't seem to change much - possibly due to removing complexity from the I/O thread. Yet another advantage is that the I/O thread doesn't have to copy packets which would slow down packet distribution, ACK generation, etc.. The buffer belongs to the call and is allocated initially at 2K, sufficiently large to hold a whole jumbo subpacket, but the buffer will be increased in size if needed. However, to take this work, MSG_PEEK may cause a later packet to be decrypted into the buffer, in which case the earlier one will need re-decrypting for a subsequent recvmsg(). Note that rx_pkt_offset may legitimately see 0 as a valid offset now, so switch to using USHRT_MAX to indicate an invalid offset. Note also that I would generally prefer to replace the buffers of the current sk_buff with a new kmalloc'd buffer of the right size, ditching the old data and frags as this makes the handling of MSG_PEEK easier and removes the re-decryption issue, but this looks like quite a complicated thing to achieve. skb_morph() looks half way to what I want, but I don't want to have to allocate a new sk_buff.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected d0d5c0cd1e711c98703f3544c1e6fc1372898de5 a05bf6d9e621fa71e89ccebe3047ba45218d7b38 git Not specified
CNA Linux Linux affected d0d5c0cd1e711c98703f3544c1e6fc1372898de5 b94a6ccbaf1104dd980150a65fdeb2f69d17d2f5 git Not specified
CNA Linux Linux affected d0d5c0cd1e711c98703f3544c1e6fc1372898de5 46cb765e2e5ad52303ea157e10d370bb6b7acbbf git Not specified
CNA Linux Linux affected d0d5c0cd1e711c98703f3544c1e6fc1372898de5 c580087743712112778a06d65a4074053072d7bf git Not specified
CNA Linux Linux affected d0d5c0cd1e711c98703f3544c1e6fc1372898de5 d2bc90cf6c75cb96d2ce549be6c35efa3099d25b git Not specified
CNA Linux Linux affected 5.3 Not specified
CNA Linux Linux unaffected 5.3 semver Not specified
CNA Linux Linux unaffected 6.6.143 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.93 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.35 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.11 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/46cb765e2e5ad52303ea157e10d370bb6b7acbbf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d2bc90cf6c75cb96d2ce549be6c35efa3099d25b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c580087743712112778a06d65a4074053072d7bf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a05bf6d9e621fa71e89ccebe3047ba45218d7b38 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b94a6ccbaf1104dd980150a65fdeb2f69d17d2f5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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