From: Kees Cook keescook@chromium.org
[ Upstream commit 474acc639fc8671fa4c1919d9e03253c82b6d321 ]
The call of mxc_jpeg_get_plane_size() from mxc_jpeg_dec_irq() sets plane_no argument to 1. The compiler sees that it's possible to end up with an access beyond the bounds of sizeimage, if mem_planes was too large:
if (plane_no >= fmt->mem_planes) // mem_planes = 2+ return 0;
if (fmt->mem_planes == fmt->comp_planes) // comp_planes != mem_planes return q_data->sizeimage[plane_no];
if (plane_no < fmt->mem_planes - 1) // mem_planes = 2 return q_data->sizeimage[plane_no];
comp_planes == 0 or 1 is safe. comp_planes > 2 would be out of bounds.
(This isn't currently possible given the contents of mxc_formats, though.)
Silence the warning by bounds checking comp_planes for future robustness. Seen with GCC 13:
In function 'mxc_jpeg_get_plane_size', inlined from 'mxc_jpeg_dec_irq' at ../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c:729:14: ../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c:641:42: warning: array subscript 2 is above array bounds of 'u32[2]' {aka 'unsigned int[2]'} [-Warray-bounds=] 641 | size += q_data->sizeimage[i]; | ~~~~~~~~~~~~~~~~~^~~ In file included from ../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.h:112, from ../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c:63: ../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.h: In function 'mxc_jpeg_dec_irq': ../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.h:84:41: note: while referencing 'sizeimage' 84 | u32 sizeimage[MXC_JPEG_MAX_PLANES]; | ^~~~~~~~~
Cc: Mirela Rabulea mirela.rabulea@nxp.com Cc: NXP Linux Team linux-imx@nxp.com Cc: Shawn Guo shawnguo@kernel.org Cc: Sascha Hauer s.hauer@pengutronix.de Cc: Pengutronix Kernel Team kernel@pengutronix.de Cc: Fabio Estevam festevam@gmail.com Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Kees Cook keescook@chromium.org Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Mauro Carvalho Chehab mchehab@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c index f085f14d676ad..c898116b763a2 100644 --- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c +++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c @@ -637,6 +637,11 @@ static u32 mxc_jpeg_get_plane_size(struct mxc_jpeg_q_data *q_data, u32 plane_no) return q_data->sizeimage[plane_no];
size = q_data->sizeimage[fmt->mem_planes - 1]; + + /* Should be impossible given mxc_formats. */ + if (WARN_ON_ONCE(fmt->comp_planes > ARRAY_SIZE(q_data->sizeimage))) + return size; + for (i = fmt->mem_planes; i < fmt->comp_planes; i++) size += q_data->sizeimage[i];