[Qemu-trivial] [PATCH 2/6] sheepdog: fix possible resouce leak and out-of-bounds access

[Gonglei]

CID 1352418 (#1 of 1): Out-of-bounds access (INCOMPATIBLE_CAST)
incompatible_cast: Pointer &snap_id points to an object whose effective
type is unsigned int (32 bits, unsigned) but is dereferenced as a wider
unsigned long (64 bits, unsigned). This may lead to memory corruption.

We also need to free local_err when ret is not equals to 0.

Signed-off-by: Gonglei <address@hidden>
---
 block/sheepdog.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/block/sheepdog.c b/block/sheepdog.c
index 8739acc..3d81bba 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -2543,7 +2543,7 @@ static int sd_snapshot_delete(BlockDriverState *bs,
                               const char *name,
                               Error **errp)
 {
-    uint32_t snap_id = 0;
+    unsigned long snap_id = 0;
     char snap_tag[SD_MAX_VDI_TAG_LEN];
     Error *local_err = NULL;
     int fd, ret;
@@ -2565,20 +2565,23 @@ static int sd_snapshot_delete(BlockDriverState *bs,
     memset(buf, 0, sizeof(buf));
     memset(snap_tag, 0, sizeof(snap_tag));
     pstrcpy(buf, SD_MAX_VDI_LEN, s->name);
-    if (qemu_strtoul(snapshot_id, NULL, 10, (unsigned long *)&snap_id)) {
+    if (qemu_strtoul(snapshot_id, NULL, 10, &snap_id)) {
         return -1;
     }
 
     if (snap_id) {
+        assert(snap_id <= UINT_MAX);
+
         hdr.snapid = snap_id;
     } else {
         pstrcpy(snap_tag, sizeof(snap_tag), snapshot_id);
         pstrcpy(buf + SD_MAX_VDI_LEN, SD_MAX_VDI_TAG_LEN, snap_tag);
     }
 
-    ret = find_vdi_name(s, s->name, snap_id, snap_tag, &vid, true,
+    ret = find_vdi_name(s, s->name, hdr.snapid, snap_tag, &vid, true,
                         &local_err);
     if (ret) {
+        error_report_err(local_err);
         return ret;
     }
 
-- 
1.8.5.2