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SubjectRe: [PATCH] drm/amdgpu: fix out of bounds write
On Wed, Oct 13, 2021 at 04:04:13PM -0400, Thelford Williams wrote:
> Size can be any value and is user controlled resulting in overwriting the
> 40 byte array wr_buf with an arbitrary length of data from buf.
>
> Signed-off-by: Thelford Williams <tdwilliamsiv@gmail.com>
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

The fix works, but unless I am missing something it is incomplete.
parse_write_buffer_into_params() is called several times, and the
size parameter is always wrong. This patch only fixes one of several
instances of the problem.

Guenter

> ---
> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
> index 814f67d86a3c..9b3ad56607bb 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
> @@ -264,7 +264,7 @@ static ssize_t dp_link_settings_write(struct file *f, const char __user *buf,
> if (!wr_buf)
> return -ENOSPC;
>
> - if (parse_write_buffer_into_params(wr_buf, size,
> + if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
> (long *)param, buf,
> max_param_num,
> &param_nums)) {
> --
> 2.33.0

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