Re: [PATCH V1] accel/amdxdna: Fix out-of-bounds memset in command slot handling

[Mario Limonciello <superm1@kernel.org>]

On 2/17/26 12:54 PM, Lizhi Hou wrote:
> The remaining space in a command slot may be smaller than the size of
> the command header. Clearing the command header with memset() before
> verifying the available slot space can result in an out-of-bounds write
> and memory corruption.
> 
> Fix this by moving the memset() call after the size validation.
> 
> Fixes: 3d32eb7a5ecf ("accel/amdxdna: Fix cu_idx being cleared by memset() during command setup")
> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
> ---
>   drivers/accel/amdxdna/aie2_message.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/accel/amdxdna/aie2_message.c b/drivers/accel/amdxdna/aie2_message.c
> index 7d7dcfeaf794..8fbbc3280468 100644
> --- a/drivers/accel/amdxdna/aie2_message.c
> +++ b/drivers/accel/amdxdna/aie2_message.c
> @@ -694,11 +694,11 @@ aie2_cmdlist_fill_npu_cf(struct amdxdna_gem_obj *cmd_bo, void *slot, size_t *siz
>   	u32 cmd_len;
>   	void *cmd;
>   
> -	memset(npu_slot, 0, sizeof(*npu_slot));
>   	cmd = amdxdna_cmd_get_payload(cmd_bo, &cmd_len);
>   	if (*size < sizeof(*npu_slot) + cmd_len)
>   		return -EINVAL;
>   
> +	memset(npu_slot, 0, sizeof(*npu_slot));
>   	npu_slot->cu_idx = amdxdna_cmd_get_cu_idx(cmd_bo);
>   	if (npu_slot->cu_idx == INVALID_CU_IDX)
>   		return -EINVAL;
> @@ -719,7 +719,6 @@ aie2_cmdlist_fill_npu_dpu(struct amdxdna_gem_obj *cmd_bo, void *slot, size_t *si
>   	u32 cmd_len;
>   	u32 arg_sz;
>   
> -	memset(npu_slot, 0, sizeof(*npu_slot));
>   	sn = amdxdna_cmd_get_payload(cmd_bo, &cmd_len);
>   	arg_sz = cmd_len - sizeof(*sn);
>   	if (cmd_len < sizeof(*sn) || arg_sz > MAX_NPU_ARGS_SIZE)
> @@ -728,6 +727,7 @@ aie2_cmdlist_fill_npu_dpu(struct amdxdna_gem_obj *cmd_bo, void *slot, size_t *si
>   	if (*size < sizeof(*npu_slot) + arg_sz)
>   		return -EINVAL;
>   
> +	memset(npu_slot, 0, sizeof(*npu_slot));
>   	npu_slot->cu_idx = amdxdna_cmd_get_cu_idx(cmd_bo);
>   	if (npu_slot->cu_idx == INVALID_CU_IDX)
>   		return -EINVAL;
> @@ -751,7 +751,6 @@ aie2_cmdlist_fill_npu_preempt(struct amdxdna_gem_obj *cmd_bo, void *slot, size_t
>   	u32 cmd_len;
>   	u32 arg_sz;
>   
> -	memset(npu_slot, 0, sizeof(*npu_slot));
>   	pd = amdxdna_cmd_get_payload(cmd_bo, &cmd_len);
>   	arg_sz = cmd_len - sizeof(*pd);
>   	if (cmd_len < sizeof(*pd) || arg_sz > MAX_NPU_ARGS_SIZE)
> @@ -760,6 +759,7 @@ aie2_cmdlist_fill_npu_preempt(struct amdxdna_gem_obj *cmd_bo, void *slot, size_t
>   	if (*size < sizeof(*npu_slot) + arg_sz)
>   		return -EINVAL;
>   
> +	memset(npu_slot, 0, sizeof(*npu_slot));
>   	npu_slot->cu_idx = amdxdna_cmd_get_cu_idx(cmd_bo);
>   	if (npu_slot->cu_idx == INVALID_CU_IDX)
>   		return -EINVAL;
> @@ -787,7 +787,6 @@ aie2_cmdlist_fill_npu_elf(struct amdxdna_gem_obj *cmd_bo, void *slot, size_t *si
>   	u32 cmd_len;
>   	u32 arg_sz;
>   
> -	memset(npu_slot, 0, sizeof(*npu_slot));
>   	pd = amdxdna_cmd_get_payload(cmd_bo, &cmd_len);
>   	arg_sz = cmd_len - sizeof(*pd);
>   	if (cmd_len < sizeof(*pd) || arg_sz > MAX_NPU_ARGS_SIZE)
> @@ -796,6 +795,7 @@ aie2_cmdlist_fill_npu_elf(struct amdxdna_gem_obj *cmd_bo, void *slot, size_t *si
>   	if (*size < sizeof(*npu_slot) + arg_sz)
>   		return -EINVAL;
>   
> +	memset(npu_slot, 0, sizeof(*npu_slot));
>   	npu_slot->type = EXEC_NPU_TYPE_ELF;
>   	npu_slot->inst_buf_addr = pd->inst_buf;
>   	npu_slot->save_buf_addr = pd->save_buf;