[Spice-devel] [PATCH] server/red_parse_qxl: add bitmap consistency check

[Alon Levy]

Just checks stride vs width times bpp.

This fixes a potential abort on guest generated bad images in
glz_encoder.

Other files touched to move some consts to red_common, they are
static so no problem to be defined in both red_worker.c and
red_parse_qxl.c .
---
 server/red_common.h    | 18 +++++++++++++++++-
 server/red_parse_qxl.c | 17 +++++++++++++++++
 server/red_worker.c    | 15 ---------------
 3 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/server/red_common.h b/server/red_common.h
index c563bc0..585b13c 100644
--- a/server/red_common.h
+++ b/server/red_common.h
@@ -25,6 +25,7 @@
 #include "common/mem.h"
 #include "common/spice_common.h"
 #include "common/messages.h"
+#include "common/lz_common.h"
 
 #include "spice.h"
 
@@ -35,13 +36,28 @@ enum {
     STREAM_VIDEO_FILTER
 };
 
+static const LzImageType MAP_BITMAP_FMT_TO_LZ_IMAGE_TYPE[] = {
+    LZ_IMAGE_TYPE_INVALID,
+    LZ_IMAGE_TYPE_PLT1_LE,
+    LZ_IMAGE_TYPE_PLT1_BE,
+    LZ_IMAGE_TYPE_PLT4_LE,
+    LZ_IMAGE_TYPE_PLT4_BE,
+    LZ_IMAGE_TYPE_PLT8,
+    LZ_IMAGE_TYPE_RGB16,
+    LZ_IMAGE_TYPE_RGB24,
+    LZ_IMAGE_TYPE_RGB32,
+    LZ_IMAGE_TYPE_RGBA,
+    LZ_IMAGE_TYPE_A8
+};
+
 static inline int bitmap_fmt_is_rgb(uint8_t fmt)
 {
     static const int BITMAP_FMT_IS_RGB[SPICE_BITMAP_FMT_ENUM_END] =
                                         {0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1};
 
     if (fmt >= SPICE_BITMAP_FMT_ENUM_END) {
-        spice_warning("fmt >= SPICE_BITMAP_FMT_ENUM_END");
+        spice_warning("fmt >= SPICE_BITMAP_FMT_ENUM_END; %d >= %d",
+                      fmt, SPICE_BITMAP_FMT_ENUM_END);
         return 0;
     }
     return BITMAP_FMT_IS_RGB[fmt];
diff --git a/server/red_parse_qxl.c b/server/red_parse_qxl.c
index bf57709..b893add 100644
--- a/server/red_parse_qxl.c
+++ b/server/red_parse_qxl.c
@@ -21,6 +21,7 @@
 
 #include <stdbool.h>
 #include <inttypes.h>
+#include "common/lz_common.h"
 #include "red_common.h"
 #include "red_memslots.h"
 #include "red_parse_qxl.h"
@@ -327,6 +328,19 @@ static SpiceChunks *red_get_image_data_chunked(RedMemSlotInfo *slots, int group_
     return data;
 }
 
+static int bitmap_consistent(SpiceBitmap *bitmap)
+{
+    int type = MAP_BITMAP_FMT_TO_LZ_IMAGE_TYPE[bitmap->format];
+    int bpp = RGB_BYTES_PER_PIXEL[type];
+
+    if (bitmap->stride < bitmap->x * bpp) {
+        spice_error("image stride too small for width: %d < %d * %d\n",
+                    bitmap->stride, bitmap->x, bpp);
+        return FALSE;
+    }
+    return TRUE;
+}
+
 // This is based on SPICE_BITMAP_FMT_*, copied from server/red_worker.c
 // to avoid a possible unoptimization from making it non static.
 static const int BITMAP_FMT_IS_RGB[] = {0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1};
@@ -382,6 +396,9 @@ static SpiceImage *red_get_image(RedMemSlotInfo *slots, int group_id,
         red->u.bitmap.x      = qxl->bitmap.x;
         red->u.bitmap.y      = qxl->bitmap.y;
         red->u.bitmap.stride = qxl->bitmap.stride;
+        if (!bitmap_consistent(&red->u.bitmap)) {
+            goto error;
+        }
         if (qxl->bitmap.palette) {
             QXLPalette *qp;
             int i, num_ents;
diff --git a/server/red_worker.c b/server/red_worker.c
index 133ba94..eee9915 100644
--- a/server/red_worker.c
+++ b/server/red_worker.c
@@ -5887,20 +5887,6 @@ static inline int _stride_is_extra(SpiceBitmap *bitmap)
     return 0;
 }
 
-static const LzImageType MAP_BITMAP_FMT_TO_LZ_IMAGE_TYPE[] = {
-    LZ_IMAGE_TYPE_INVALID,
-    LZ_IMAGE_TYPE_PLT1_LE,
-    LZ_IMAGE_TYPE_PLT1_BE,
-    LZ_IMAGE_TYPE_PLT4_LE,
-    LZ_IMAGE_TYPE_PLT4_BE,
-    LZ_IMAGE_TYPE_PLT8,
-    LZ_IMAGE_TYPE_RGB16,
-    LZ_IMAGE_TYPE_RGB24,
-    LZ_IMAGE_TYPE_RGB32,
-    LZ_IMAGE_TYPE_RGBA,
-    LZ_IMAGE_TYPE_A8
-};
-
 typedef struct compress_send_data_t {
     void*    comp_buf;
     uint32_t comp_buf_size;
@@ -5908,7 +5894,6 @@ typedef struct compress_send_data_t {
     int is_lossy;
 } compress_send_data_t;
 
-
 static inline int red_glz_compress_image(DisplayChannelClient *dcc,
                                          SpiceImage *dest, SpiceBitmap *src, Drawable *drawable,
                                          compress_send_data_t* o_comp_data)
-- 
1.7.12