It looks good to me.
Reviewed-by: Tom Chung <chiahsuan.ch...@amd.com>
<mailto:chiahsuan.ch...@amd.com>
On 1/30/2024 5:49 PM, SHANMUGAM, SRINIVASAN wrote:
[AMD Official Use Only - General]
*From:* SHANMUGAM, SRINIVASAN
*Sent:* Tuesday, January 30, 2024 3:18 PM
*To:* Siqueira, Rodrigo <rodrigo.sique...@amd.com>; Pillai, Aurabindo
<aurabindo.pil...@amd.com>
*Cc:* Cyr, Aric <aric....@amd.com>; amd-gfx@lists.freedesktop.org;
Somasundaram, Meenakshikumar <meenakshikumar.somasunda...@amd.com>;
Huang, PeiChen (Pei-Chen) <peichen.hu...@amd.com>
*Subject:* Re: [PATCH] drm/amd/display: Fix buffer overflow in
'get_host_router_total_dp_tunnel_bw()'
+ Cc: Tom Chung <chiahsuan.ch...@amd.com>
On 1/29/2024 9:19 PM, Srinivasan Shanmugam wrote:
The error message buffer overflow 'dc->links' 12 <= 12 suggests that the
code is trying to access an element of the dc->links array that is
beyond its bounds. In C, arrays are zero-indexed, so an array with 12
elements has valid indices from 0 to 11. Trying to access dc->links[12]
would be an attempt to access the 13th element of a 12-element array,
which is a buffer overflow.
To fix this, ensure that the loop does not go beyond the last valid
index when accessing dc->links[i + 1] by subtracting 1 from the loop
condition.
This would ensure that i + 1 is always a valid index in the array.
Fixes the below:
drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_dp_dpia_bw.c:208
get_host_router_total_dp_tunnel_bw() error: buffer overflow 'dc->links' 12 <= 12
Fixes: 9ed0893b7c58 ("drm/amd/display: Add dpia display mode validation
logic")
Cc: PeiChen Huang<peichen.hu...@amd.com> <mailto:peichen.hu...@amd.com>
Cc: Aric Cyr<aric....@amd.com> <mailto:aric....@amd.com>
Cc: Rodrigo Siqueira<rodrigo.sique...@amd.com>
<mailto:rodrigo.sique...@amd.com>
Cc: Aurabindo Pillai<aurabindo.pil...@amd.com>
<mailto:aurabindo.pil...@amd.com>
Cc: Meenakshikumar Somasundaram<meenakshikumar.somasunda...@amd.com>
<mailto:meenakshikumar.somasunda...@amd.com>
Signed-off-by: Srinivasan Shanmugam<srinivasan.shanmu...@amd.com>
<mailto:srinivasan.shanmu...@amd.com>
---
drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git
a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c
b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c
index dd0d2b206462..5491b707cec8 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c
@@ -196,7 +196,7 @@ static int get_host_router_total_dp_tunnel_bw(const
struct dc *dc, uint8_t hr_in
struct dc_link *link_dpia_primary, *link_dpia_secondary;
int total_bw = 0;
- for (uint8_t i = 0; i < MAX_PIPES * 2; ++i) {
+ for (uint8_t i = 0; i < (MAX_PIPES * 2) - 1; ++i) {
if (!dc->links[i] || dc->links[i]->ep_type !=
DISPLAY_ENDPOINT_USB4_DPIA)
continue;
