Re: [PATCH] accel/qaic: use sizeof(*trans_hdr) for transaction length check

From: Jeff Hugo

Date: Wed Jul 29 2026 - 16:59:00 EST


On 6/17/2026 3:25 PM, Muhammad Bilal wrote:
In encode_message() the per-transaction lower-bound check compares
trans_hdr->len against sizeof(trans_hdr), i.e. the size of the pointer,
instead of sizeof(*trans_hdr), the size of struct qaic_manage_trans_hdr.

Every other length check in this file (encode_message() at the loop
guard, decode_message(), etc.) correctly uses sizeof(*trans_hdr), so
this is an inconsistency. On 64-bit builds the pointer and the struct
are both 8 bytes, so the check is correct by coincidence and there is
no behavioural change. On 32-bit builds the pointer is 4 bytes, which
weakens the minimum-length check below the 8-byte header size.

Use sizeof(*trans_hdr) so the check validates against the actual
transaction header size on all builds.

Fixes: ea33cb6fc278 ("accel/qaic: tighten bounds checking in encode_message()")
Signed-off-by: Muhammad Bilal <meatuni001@xxxxxxxxx>

Reviewed-by: Jeff Hugo <jeff.hugo@xxxxxxxxxxxxxxxx>