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CVE-2026-46064

ibmasm: fix heap over-read in ibmasm_send_i2o_message()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, and 2 more
None on Exploit-DB, Metasploit or GitHub

Summary

In 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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in ca1c857e2bb74a9fc0606128334f85316d57067b; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in b870f652877bfbe321bd0f4096fc37a93296f7b6; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in ce57fa439bd1b5d664f334a0c3e3f0e42abb0153; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in fd19eb1c75047a4ed4e855f56cafd704dc3914e0; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in fe31722b0194ff76bf8b461e8bf97a2081147787; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in c1c2417c60dbdca5ebb00462f21ee71c2d7f7083; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 9e8f6c9d4ecddda2f28baa1678340286cff3969c; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 9aad71144fa3682cca3837a06c8623016790e7ec

  • Linux Linux

    2.6.12

  • KernelLinux

    From 2.6.12 · fixed in 5.10.258; From 5.11.0 · fixed in 5.15.209; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.140; From 6.7.0 · fixed in 6.12.86; From 6.13.0 · fixed in 6.18.27; From 6.19.0 · fixed in 7.0.4

References 8

git.kernel.org