diff options
| author | Harry Wentland <harry.wentland@amd.com> | 2026-05-04 11:14:45 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2026-05-19 12:13:07 -0400 |
| commit | cd86529ec61474a38c3837fb7823790a7c3f8cce (patch) | |
| tree | 41524159f7829b4d06e25a1dca3dbcf1ab3ec059 /drivers/gpu | |
| parent | 6dc2c49a705195c89b09b134d0bc4dc5e42d1fea (diff) | |
drm/amd/display: Fix integer overflow in bios_get_image()
[Why&How]
The bounds check in bios_get_image() computes 'offset + size' using
unsigned 32-bit arithmetic before comparing against bios_size. If a
VBIOS image contains a near-UINT32_MAX offset the addition wraps to a
small value, the comparison passes, and the function returns a wild
pointer past the VBIOS mapping.
Additionally, the comparison uses '<' (strict), which incorrectly
rejects the valid exact-fit case where offset + size == bios_size.
Fix both issues by restructuring the check to avoid the addition
entirely: first reject if offset alone exceeds bios_size, then check
size against the remaining space (bios_size - offset). This eliminates
the overflow and correctly permits exact-fit accesses.
Assisted-by: GitHub Copilot:claude-opus-4.6
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit d40fb392af659c4a02b560319f226842f6ec1a95)
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/bios/bios_parser_helper.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/bios/bios_parser_helper.c b/drivers/gpu/drm/amd/display/dc/bios/bios_parser_helper.c index 8d2cf95ae739..e00dc05c2d9d 100644 --- a/drivers/gpu/drm/amd/display/dc/bios/bios_parser_helper.c +++ b/drivers/gpu/drm/amd/display/dc/bios/bios_parser_helper.c @@ -37,10 +37,13 @@ uint8_t *bios_get_image(struct dc_bios *bp, uint32_t offset, uint32_t size) { - if (bp->bios && offset + size < bp->bios_size) - return bp->bios + offset; - else + if (!bp->bios) return NULL; + + if (offset > bp->bios_size || size > bp->bios_size - offset) + return NULL; + + return bp->bios + offset; } #include "reg_helper.h" |