[Qemu-devel] [PULL 11/17] block: Don't copy backing file name on error

[Kevin Wolf]

From: Max Reitz <address@hidden>

bdrv_open_backing_file() tries to copy the backing file name using
pstrcpy directly after calling bdrv_open() to open the backing file
without checking whether that was actually successful. If it was not,
ps->backing_hd->file will probably be NULL and qemu will crash.

Fix this by moving pstrcpy after checking whether bdrv_open() succeeded.

Signed-off-by: Max Reitz <address@hidden>
Reviewed-by: Benoit Canet <address@hidden>
Reviewed-by: Amos Kong <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
 block.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block.c b/block.c
index fd05a80..366999b 100644
--- a/block.c
+++ b/block.c
@@ -1004,8 +1004,6 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict 
*options, Error **errp)
     ret = bdrv_open(bs->backing_hd,
                     *backing_filename ? backing_filename : NULL, options,
                     back_flags, back_drv, &local_err);
-    pstrcpy(bs->backing_file, sizeof(bs->backing_file),
-            bs->backing_hd->file->filename);
     if (ret < 0) {
         bdrv_unref(bs->backing_hd);
         bs->backing_hd = NULL;
@@ -1013,6 +1011,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict 
*options, Error **errp)
         error_propagate(errp, local_err);
         return ret;
     }
+    pstrcpy(bs->backing_file, sizeof(bs->backing_file),
+            bs->backing_hd->file->filename);
     return 0;
 }
 
-- 
1.8.1.4