ibmasm: fix heap over-read in ibmasm_send_i2o_message()

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Summary

CVECVE-2026-46064
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-27 14:17:26 UTC
Updated2026-06-01 17:17:22 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ibmasm: fix heap over-read in ibmasm_send_i2o_message() The ibmasm_send_i2o_message() function uses get_dot_command_size() to compute the byte count for memcpy_toio(), but this value is derived from user-controlled fields in the dot_command_header (command_size: u8, data_size: u16) and is never validated against the actual allocation size. A root user can write a small buffer with inflated header fields, causing memcpy_toio() to read up to ~65 KB past the end of the allocation into adjacent kernel heap, which is then forwarded to the service processor over MMIO. Silently clamping the copy size is not sufficient: if the header fields claim a larger size than the buffer, the SP receives a dot command whose own header is inconsistent with the I2O message length, which can cause the SP to desynchronize. Reject such commands outright by returning failure. Validate command_size before calling get_mfa_inbound() to avoid leaking an I2O message frame: reading INBOUND_QUEUE_PORT dequeues a hardware frame from the controller's free pool, and returning without a corresponding set_mfa_inbound() call would permanently exhaust it. Additionally, clamp command_size to I2O_COMMAND_SIZE before the memcpy_toio() so the MMIO write stays within the I2O message frame, consistent with the clamping already performed by outgoing_message_size() for the header field.

Risk And Classification

EPSS: 0.000320000 probability, percentile 0.097530000 (date 2026-06-02)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ca1c857e2bb74a9fc0606128334f85316d57067b git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 b870f652877bfbe321bd0f4096fc37a93296f7b6 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ce57fa439bd1b5d664f334a0c3e3f0e42abb0153 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 fd19eb1c75047a4ed4e855f56cafd704dc3914e0 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 fe31722b0194ff76bf8b461e8bf97a2081147787 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 c1c2417c60dbdca5ebb00462f21ee71c2d7f7083 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 9e8f6c9d4ecddda2f28baa1678340286cff3969c git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 9aad71144fa3682cca3837a06c8623016790e7ec git Not specified
CNA Linux Linux affected 2.6.12 Not specified
CNA Linux Linux unaffected 2.6.12 semver Not specified
CNA Linux Linux unaffected 5.10.258 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.209 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.175 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.140 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.86 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.27 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.4 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/ce57fa439bd1b5d664f334a0c3e3f0e42abb0153 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9e8f6c9d4ecddda2f28baa1678340286cff3969c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b870f652877bfbe321bd0f4096fc37a93296f7b6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/fd19eb1c75047a4ed4e855f56cafd704dc3914e0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c1c2417c60dbdca5ebb00462f21ee71c2d7f7083 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9aad71144fa3682cca3837a06c8623016790e7ec 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ca1c857e2bb74a9fc0606128334f85316d57067b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/fe31722b0194ff76bf8b461e8bf97a2081147787 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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