[ Upstream commit 96d3c1cade ]
The encode_dma() function has some validation on in_trans->size but it
would be more clear to move those checks to find_and_map_user_pages().
The encode_dma() had two checks:
if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size)
return -EINVAL;
The in_trans->addr variable is the starting address. The in_trans->size
variable is the total size of the transfer. The transfer can occur in
parts and the resources->xferred_dma_size tracks how many bytes we have
already transferred.
This patch introduces a new variable "remaining" which represents the
amount we want to transfer (in_trans->size) minus the amount we have
already transferred (resources->xferred_dma_size).
I have modified the check for if in_trans->size is zero to instead check
if in_trans->size is less than resources->xferred_dma_size. If we have
already transferred more bytes than in_trans->size then there are negative
bytes remaining which doesn't make sense. If there are zero bytes
remaining to be copied, just return success.
The check in encode_dma() checked that "addr + size" could not overflow
and barring a driver bug that should work, but it's easier to check if
we do this in parts. First check that "in_trans->addr +
resources->xferred_dma_size" is safe. Then check that "xfer_start_addr +
remaining" is safe.
My final concern was that we are dealing with u64 values but on 32bit
systems the kmalloc() function will truncate the sizes to 32 bits. So
I calculated "total = in_trans->size + offset_in_page(xfer_start_addr);"
and returned -EINVAL if it were >= SIZE_MAX. This will not affect 64bit
systems.
Fixes: 129776ac2e ("accel/qaic: Add control path")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Carl Vanderlip <quic_carlv@quicinc.com>
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Link: https://patchwork.freedesktop.org/patch/msgid/24d3348b-25ac-4c1b-b171-9dae7c43e4e0@moroto.mountain
Signed-off-by: Sasha Levin <sashal@kernel.org>
d410a96e5c