CVE-2026-74712vdpa/mlx5: Fix buffer length in create_direct_keys()

Official description

In the Linux kernel, the following vulnerability has been resolved: vdpa/mlx5: Fix buffer length in create_direct_keys() We have seen in our CI the following KASAN message: BUG: KASAN: slab-out-of-bounds in cmd_exec+0x550/0xca0 [mlx5_core] Read of size 272 at addr 0000000176795020 by task qemu-system-s39/82764 [...] [<000011388ab3a7a0>] cmd_exec+0x550/0xca0 [mlx5_core] [<000011388ab3b61c>] mlx5_cmd_exec_cb+0x25c/0x4f0 [mlx5_core] [<000011388b21e82e>] mlx5_vdpa_exec_async_cmds+0x22e/0x5e0 [mlx5_vdpa] [<000011388b21fd44>] create_direct_keys+0x954/0xef0 [mlx5_vdpa] [...] The buggy address is located 4128 bytes inside of allocated 4384-byte region [0000000176794000, 0000000176795120) So in essence we read 16 bytes beyond 4384-byte allocation. create_direct_keys calculates the pointer and length for in and out buffers. The size calculation for in includes the entire structure size (out + in + mtt[]) but the pointer passed to cmd_exec points only to the 'in' field, skipping the 'out' field. This causes mlx5_copy_to_msg() to read beyond the allocated buffer by sizeof(out) bytes when copying command data. Properly calculate the input size to match the pointer and allocation size.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/ec3bb289cf19d526224117d5d450a5fd9cbd5ab2
• https://git.kernel.org/stable/c/cde8931a25392670dd59a0acfcab87a830ab66c5
• https://git.kernel.org/stable/c/6c8a9f7bc00301e533a5366384f3070a8e7f8430
• https://git.kernel.org/stable/c/727e1f569855df83579edbd73dcb4a0723543a12