From:   Kees Cook <keescook@chromium.org>
To:     Ben Skeggs <bskeggs@redhat.com>
Cc:     Kees Cook <keescook@chromium.org>, Lyude Paul <lyude@redhat.com>,
        Karol Herbst <kherbst@redhat.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Dave Airlie <airlied@redhat.com>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
        dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH] drm/nouveau/disp: More DP_RECEIVER_CAP_SIZE array fixes
Date:   Sat,  4 Feb 2023 10:43:10 -0800
Message-Id: <20230204184307.never.825-kees@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

More arrays (and arguments) for dcpd were set to 16, when it looks like
DP_RECEIVER_CAP_SIZE (15) should be used. Fix the remaining cases, seen
with GCC 13:

../drivers/gpu/drm/nouveau/nvif/outp.c: In function 'nvif_outp_acquire_dp':
../include/linux/fortify-string.h:57:33: warning: array subscript 'unsigned char[16][0]' is partly outside array bounds of 'u8[15]' {aka 'unsigned char[15]'} [-Warray-bounds=]
   57 | #define __underlying_memcpy     __builtin_memcpy
      |                                 ^
...
../drivers/gpu/drm/nouveau/nvif/outp.c:140:9: note: in expansion of macro 'memcpy'
  140 |         memcpy(args.dp.dpcd, dpcd, sizeof(args.dp.dpcd));
      |         ^~~~~~
../drivers/gpu/drm/nouveau/nvif/outp.c:130:49: note: object 'dpcd' of size [0, 15]
  130 | nvif_outp_acquire_dp(struct nvif_outp *outp, u8 dpcd[DP_RECEIVER_CAP_SIZE],
      |                                              ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 813443721331 ("drm/nouveau/disp: move DP link config into acquire")
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/gpu/drm/nouveau/include/nvif/if0012.h    | 4 +++-
 drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.h  | 3 ++-
 drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/include/nvif/if0012.h b/drivers/gpu/drm/nouveau/include/nvif/if0012.h
index eb99d84eb844..16d4ad5023a3 100644
--- a/drivers/gpu/drm/nouveau/include/nvif/if0012.h
+++ b/drivers/gpu/drm/nouveau/include/nvif/if0012.h
@@ -2,6 +2,8 @@
 #ifndef __NVIF_IF0012_H__
 #define __NVIF_IF0012_H__
 
+#include <drm/display/drm_dp.h>
+
 union nvif_outp_args {
 	struct nvif_outp_v0 {
 		__u8 version;
@@ -63,7 +65,7 @@ union nvif_outp_acquire_args {
 				__u8 hda;
 				__u8 mst;
 				__u8 pad04[4];
-				__u8 dpcd[16];
+				__u8 dpcd[DP_RECEIVER_CAP_SIZE];
 			} dp;
 		};
 	} v0;
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.h b/drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.h
index b7631c1ab242..4e7f873f66e2 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.h
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.h
@@ -3,6 +3,7 @@
 #define __NVKM_DISP_OUTP_H__
 #include "priv.h"
 
+#include <drm/display/drm_dp.h>
 #include <subdev/bios.h>
 #include <subdev/bios/dcb.h>
 #include <subdev/bios/dp.h>
@@ -42,7 +43,7 @@ struct nvkm_outp {
 			bool aux_pwr_pu;
 			u8 lttpr[6];
 			u8 lttprs;
-			u8 dpcd[16];
+			u8 dpcd[DP_RECEIVER_CAP_SIZE];
 
 			struct {
 				int dpcd; /* -1, or index into SUPPORTED_LINK_RATES table */
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c
index 4f0ca709c85a..fc283a4a1522 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c
@@ -146,7 +146,7 @@ nvkm_uoutp_mthd_release(struct nvkm_outp *outp, void *argv, u32 argc)
 }
 
 static int
-nvkm_uoutp_mthd_acquire_dp(struct nvkm_outp *outp, u8 dpcd[16],
+nvkm_uoutp_mthd_acquire_dp(struct nvkm_outp *outp, u8 dpcd[DP_RECEIVER_CAP_SIZE],
 			   u8 link_nr, u8 link_bw, bool hda, bool mst)
 {
 	int ret;
-- 
2.34.1