This is a note to let you know that I've just added the patch titled
drm/mediatek: Fix coverity issue with unintentional integer overflow
to the 6.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-mediatek-fix-coverity-issue-with-unintentional-i.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4b20b3ddb3e617026bcfa4810cb01875c27e8e2c
Author: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>
Date: Thu Sep 7 17:14:25 2023 +0800
drm/mediatek: Fix coverity issue with unintentional integer overflow
[ Upstream commit b0b0d811eac6b4c52cb9ad632fa6384cf48869e7 ]
1. Instead of multiplying 2 variable of different types. Change to
assign a value of one variable and then multiply the other variable.
2. Add a int variable for multiplier calculation instead of calculating
different types multiplier with dma_addr_t variable directly.
Fixes: 1a64a7aff8da ("drm/mediatek: Fix cursor plane no update")
Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>
Reviewed-by: Alexandre Mergnat <amergnat@xxxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20230907091425.9526-1-jason-jh.lin@xxxxxxxxxxxx/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.c b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
index 0e0a41b2f57f0..4f2e3feabc0f8 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
@@ -121,7 +121,14 @@ int mtk_drm_gem_dumb_create(struct drm_file *file_priv, struct drm_device *dev,
int ret;
args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
- args->size = args->pitch * args->height;
+
+ /*
+ * Multiply 2 variables of different types,
+ * for example: args->size = args->spacing * args->height;
+ * may cause coverity issue with unintentional overflow.
+ */
+ args->size = args->pitch;
+ args->size *= args->height;
mtk_gem = mtk_drm_gem_create(dev, args->size, false);
if (IS_ERR(mtk_gem))
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_plane.c b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
index 31f9420aff6f8..308fe7e8106d1 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_plane.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
@@ -145,6 +145,7 @@ static void mtk_plane_update_new_state(struct drm_plane_state *new_state,
dma_addr_t addr;
dma_addr_t hdr_addr = 0;
unsigned int hdr_pitch = 0;
+ int offset;
gem = fb->obj[0];
mtk_gem = to_mtk_gem_obj(gem);
@@ -154,8 +155,15 @@ static void mtk_plane_update_new_state(struct drm_plane_state *new_state,
modifier = fb->modifier;
if (modifier == DRM_FORMAT_MOD_LINEAR) {
- addr += (new_state->src.x1 >> 16) * fb->format->cpp[0];
- addr += (new_state->src.y1 >> 16) * pitch;
+ /*
+ * Using dma_addr_t variable to calculate with multiplier of different types,
+ * for example: addr += (new_state->src.x1 >> 16) * fb->format->cpp[0];
+ * may cause coverity issue with unintentional overflow.
+ */
+ offset = (new_state->src.x1 >> 16) * fb->format->cpp[0];
+ addr += offset;
+ offset = (new_state->src.y1 >> 16) * pitch;
+ addr += offset;
} else {
int width_in_blocks = ALIGN(fb->width, AFBC_DATA_BLOCK_WIDTH)
/ AFBC_DATA_BLOCK_WIDTH;
@@ -163,21 +171,34 @@ static void mtk_plane_update_new_state(struct drm_plane_state *new_state,
/ AFBC_DATA_BLOCK_HEIGHT;
int x_offset_in_blocks = (new_state->src.x1 >> 16) / AFBC_DATA_BLOCK_WIDTH;
int y_offset_in_blocks = (new_state->src.y1 >> 16) / AFBC_DATA_BLOCK_HEIGHT;
- int hdr_size;
+ int hdr_size, hdr_offset;
hdr_pitch = width_in_blocks * AFBC_HEADER_BLOCK_SIZE;
pitch = width_in_blocks * AFBC_DATA_BLOCK_WIDTH *
AFBC_DATA_BLOCK_HEIGHT * fb->format->cpp[0];
hdr_size = ALIGN(hdr_pitch * height_in_blocks, AFBC_HEADER_ALIGNMENT);
+ hdr_offset = hdr_pitch * y_offset_in_blocks +
+ AFBC_HEADER_BLOCK_SIZE * x_offset_in_blocks;
+
+ /*
+ * Using dma_addr_t variable to calculate with multiplier of different types,
+ * for example: addr += hdr_pitch * y_offset_in_blocks;
+ * may cause coverity issue with unintentional overflow.
+ */
+ hdr_addr = addr + hdr_offset;
- hdr_addr = addr + hdr_pitch * y_offset_in_blocks +
- AFBC_HEADER_BLOCK_SIZE * x_offset_in_blocks;
/* The data plane is offset by 1 additional block. */
- addr = addr + hdr_size +
- pitch * y_offset_in_blocks +
- AFBC_DATA_BLOCK_WIDTH * AFBC_DATA_BLOCK_HEIGHT *
- fb->format->cpp[0] * (x_offset_in_blocks + 1);
+ offset = pitch * y_offset_in_blocks +
+ AFBC_DATA_BLOCK_WIDTH * AFBC_DATA_BLOCK_HEIGHT *
+ fb->format->cpp[0] * (x_offset_in_blocks + 1);
+
+ /*
+ * Using dma_addr_t variable to calculate with multiplier of different types,
+ * for example: addr += pitch * y_offset_in_blocks;
+ * may cause coverity issue with unintentional overflow.
+ */
+ addr = addr + hdr_size + offset;
}
mtk_plane_state->pending.enable = true;
