From: Jason-JH.Lin Date: Thu, 7 Sep 2023 09:14:25 +0000 (+0800) Subject: drm/mediatek: Fix coverity issue with unintentional integer overflow X-Git-Tag: v6.1.132~9 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a12bd675100531f9fb4508fd4430dd1632325a0e;p=thirdparty%2Fkernel%2Fstable.git drm/mediatek: Fix coverity issue with unintentional integer overflow commit b0b0d811eac6b4c52cb9ad632fa6384cf48869e7 upstream. 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 Reviewed-by: Alexandre Mergnat Reviewed-by: AngeloGioacchino Del Regno Link: https://patchwork.kernel.org/project/dri-devel/patch/20230907091425.9526-1-jason-jh.lin@mediatek.com/ Signed-off-by: Chun-Kuang Hu [ For certain code segments with coverity issue do not exist in function mtk_plane_update_new_state(), those not present in v6.1 are not back ported. ] Signed-off-by: Bin Lan Signed-off-by: He Zhe Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.c b/drivers/gpu/drm/mediatek/mtk_drm_gem.c index 21e584038581d..336a6ee792c6f 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_gem.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.c @@ -119,7 +119,14 @@ 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 30d361671aa9c..fb062e52eb123 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_plane.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_plane.c @@ -120,6 +120,7 @@ static void mtk_plane_update_new_state(struct drm_plane_state *new_state, struct mtk_drm_gem_obj *mtk_gem; unsigned int pitch, format; dma_addr_t addr; + int offset; gem = fb->obj[0]; mtk_gem = to_mtk_gem_obj(gem); @@ -127,8 +128,16 @@ static void mtk_plane_update_new_state(struct drm_plane_state *new_state, pitch = fb->pitches[0]; format = fb->format->format; - 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; + mtk_plane_state->pending.enable = true; mtk_plane_state->pending.pitch = pitch;