6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zack Rusin [ Upstream commit 21bc51cb89ced74d6645a138cc2f21184bc75094 ] Validate the pitch, alongside the box dimensions before trying to copy data from the underlying surface. Fixes possible out of bounds reads with cursor snooping. Fixes: 2ac863719e51 ("vmwgfx: Snoop DMA transfers with non-covering sizes") Cc: stable@vger.kernel.org Reported-by: Youness HFA Signed-off-by: Zack Rusin Reviewed-by: Maaz Mombasawala Link: https://patch.msgid.link/20260809204515.211045-1-zack.rusin@broadcom.com [ sashal: Adjusted context for vmw_kms_cursor_snoop() residing in the KMS code. ] Signed-off-by: Sasha Levin --- drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c index 33f73d559be72..7524403427c7b 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c @@ -370,6 +370,7 @@ void vmw_kms_cursor_snoop(struct vmw_surface *srf, unsigned long kmap_num; SVGA3dCopyBox *box; unsigned box_count; + u64 src_extent; void *virtual; bool is_iomem; struct vmw_dma_cmd { @@ -381,6 +382,8 @@ void vmw_kms_cursor_snoop(struct vmw_surface *srf, vmw_surface_get_desc(VMW_CURSOR_SNOOP_FORMAT); const u32 image_pitch = VMW_CURSOR_SNOOP_WIDTH * desc->pitchBytesPerBlock; + BUILD_BUG_ON(sizeof(*srf->snooper.image) != desc->pitchBytesPerBlock); + cmd = container_of(header, struct vmw_dma_cmd, header); /* No snooper installed, nothing to copy */ @@ -418,8 +421,19 @@ void vmw_kms_cursor_snoop(struct vmw_surface *srf, return; } + if (box->w == 0 || box->h == 0) + return; + + src_extent = (u64)(box->h - 1) * cmd->dma.guest.pitch + + (u64)box->w * desc->pitchBytesPerBlock; + if (src_extent > bo->base.size) { + DRM_ERROR("Cursor snoop source of %llu bytes exceeds the %zu byte buffer\n", + src_extent, bo->base.size); + return; + } + kmap_offset = cmd->dma.guest.ptr.offset >> PAGE_SHIFT; - kmap_num = (VMW_CURSOR_SNOOP_HEIGHT*image_pitch) >> PAGE_SHIFT; + kmap_num = PFN_UP(src_extent); ret = ttm_bo_reserve(bo, true, false, NULL); if (unlikely(ret != 0)) { @@ -433,14 +447,16 @@ void vmw_kms_cursor_snoop(struct vmw_surface *srf, virtual = ttm_kmap_obj_virtual(&map, &is_iomem); - if (box->w == VMW_CURSOR_SNOOP_WIDTH && cmd->dma.guest.pitch == image_pitch) { + if (box->w == VMW_CURSOR_SNOOP_WIDTH && + box->h == VMW_CURSOR_SNOOP_HEIGHT && + cmd->dma.guest.pitch == image_pitch) { memcpy(srf->snooper.image, virtual, VMW_CURSOR_SNOOP_HEIGHT*image_pitch); } else { - /* Image is unsigned pointer. */ + /* The destination stride is in pixels. */ for (i = 0; i < box->h; i++) - memcpy(srf->snooper.image + i * image_pitch, - virtual + i * cmd->dma.guest.pitch, + memcpy(srf->snooper.image + i * VMW_CURSOR_SNOOP_WIDTH, + virtual + (size_t)i * cmd->dma.guest.pitch, box->w * desc->pitchBytesPerBlock); } -- 2.53.0