CVE-2026-46064
published 2026-05-27CVE-2026-46064: 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()…
medium5.5
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.
Affected
10 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| linux | linux | — | — |
| linux | linux | >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ca1c857e2bb74a9fc0606128334f85316d57067b | ca1c857e2bb74a9fc0606128334f85316d57067b |
| linux | linux | >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b870f652877bfbe321bd0f4096fc37a93296f7b6 | b870f652877bfbe321bd0f4096fc37a93296f7b6 |
| linux | linux | >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ce57fa439bd1b5d664f334a0c3e3f0e42abb0153 | ce57fa439bd1b5d664f334a0c3e3f0e42abb0153 |
| linux | linux | >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < fd19eb1c75047a4ed4e855f56cafd704dc3914e0 | fd19eb1c75047a4ed4e855f56cafd704dc3914e0 |
| linux | linux | >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < fe31722b0194ff76bf8b461e8bf97a2081147787 | fe31722b0194ff76bf8b461e8bf97a2081147787 |
| linux | linux | >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c1c2417c60dbdca5ebb00462f21ee71c2d7f7083 | c1c2417c60dbdca5ebb00462f21ee71c2d7f7083 |
| linux | linux | >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9e8f6c9d4ecddda2f28baa1678340286cff3969c | 9e8f6c9d4ecddda2f28baa1678340286cff3969c |
| linux | linux | >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9aad71144fa3682cca3837a06c8623016790e7ec | 9aad71144fa3682cca3837a06c8623016790e7ec |
| linux | linux_kernel | — | — |