vvfat: Fix segfault on write to read-only disk

vvfat tries to set the readonly flag in its open function, but nowadays this is overwritted with the readonly=... command line option. Check in bdrv_write if the vvfat was opened read-only and return an error in this case. Without this check, vvfat tries to access the qcow bs, which is NULL without enabled write support. Signed-off-by: Kevin Wolf <[email protected]>
0x3h · Sep 21, 2010 · ac48e38 · ac48e38
1 parent a287916
commit ac48e38
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/block/vvfat.c b/block/vvfat.c
@@ -2665,6 +2665,11 @@ static int vvfat_write(BlockDriverState *bs, int64_t sector_num,
 
 DLOG(checkpoint());
 
+    /* Check if we're operating in read-only mode */
+    if (s->qcow == NULL) {
+        return -EACCES;
+    }
+
     vvfat_close_current_file(s);
 
     /*