6.6-stable review patch. If anyone has any objections, please let me know.
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From: Srinivasan Shanmugam srinivasan.shanmugam@amd.com
commit 97cba232549b9fe7e491fb60a69cf93075015f29 upstream.
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: 59f1622a5f05 ("drm/amd/display: Add dpia display mode validation logic") Cc: PeiChen Huang peichen.huang@amd.com Cc: Aric Cyr aric.cyr@amd.com Cc: Rodrigo Siqueira rodrigo.siqueira@amd.com Cc: Aurabindo Pillai aurabindo.pillai@amd.com Cc: Meenakshikumar Somasundaram meenakshikumar.somasundaram@amd.com Signed-off-by: Srinivasan Shanmugam srinivasan.shanmugam@amd.com Reviewed-by: Tom Chung chiahsuan.chung@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 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_tunn 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;