Commit 25a1a08f authored by Harry Wentland's avatar Harry Wentland Committed by Alex Deucher
Browse files

drm/amd/display: Don't allow partial copy_from_user 

There is no reason to allow for partial buffers from userspace in our
debugfs. In this particular case callers will zero out the wr_buf but if
callers in the future don't do that we might be looking at corrupt data.

Linus puts it better than I can in
https://lkml.org/lkml/2021/10/26/993



Reviewed-by: default avatarRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: default avatarHarry Wentland <harry.wentland@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 78469728

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c

+4 −6
Original line number Diff line number Diff line
@@ -78,12 +78,10 @@ static int parse_write_buffer_into_params(char *wr_buf, uint32_t wr_buf_size, 


	wr_buf_ptr = wr_buf;



	r = copy_from_user(wr_buf_ptr, buf, wr_buf_size);



	/* r is bytes not be copied */

	if (r >= wr_buf_size) {

		DRM_DEBUG_DRIVER("user data not be read\n");

		return -EINVAL;

	if (copy_from_user(wr_buf_ptr, buf, wr_buf_size)) {

		DRM_DEBUG_DRIVER("user data could not be read successfully\n");

		return -EFAULT;

	}



	/* check number of parameters. isspace could not differ space and \n */