Re: [libvirt] [PATCH] storage: avoid null deref on qemu-img failure
Dňa 21.10.2011 23:39, Eric Blake wrote / napísal(a):
Detected by Coverity. Only possible if qemu-img gives bogus output,
but we might as well be robust.
* src/storage/storage_backend.c
(virStorageBackendQEMUImgBackingFormat): Check for strstr failure.
---
src/storage/storage_backend.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index 64c35c2..7c8bfdc 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -631,8 +631,9 @@ static int virStorageBackendQEMUImgBackingFormat(const char
*qemuimg)
if (virCommandRun(cmd,&exitstatus)< 0)
goto cleanup;
- start = strstr(help, " create ");
- end = strstr(start, "\n");
+ if ((start = strstr(help, " create ")) == NULL ||
+ (end = strstr(start, "\n")) == NULL)
+ goto cleanup;
At least one call graph to this function does not contain adding a error
message of any kind. I think it would be fair to inform the user if his
qemu-img is somehow broken (although unlikely to happen), if we check
for this now.
if (((tmp = strstr(start, "-F fmt"))&&
tmp< end) ||
((tmp = strstr(start, "-F backing_fmt"))&& tmp< end))
ret = QEMU_IMG_BACKING_FORMAT_FLAG;
ACK,
Peter.