[Qemu-devel] [PATCH stable-0.15 29/36] vmdk: Fix possible segfaults

[Andreas Färber]

From: Kevin Wolf <address@hidden>

Data we read from the disk isn't necessarily null terminated and may not
contain the string we're looking for. The code needs to be a bit more careful
here.

Signed-off-by: Kevin Wolf <address@hidden>
(cherry picked from commit 93897b9fd43548e9c15cf8bece2d9e5174b01fc7)

Signed-off-by: Bruce Rogers <address@hidden>
Signed-off-by: Andreas Färber <address@hidden>
---
 block/vmdk.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index 8284747..f4fce08 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -196,6 +196,7 @@ static uint32_t vmdk_read_cid(BlockDriverState *bs, int 
parent)
         cid_str_size = sizeof("CID");
     }
 
+    desc[DESC_SIZE - 1] = '\0';
     p_name = strstr(desc, cid_str);
     if (p_name != NULL) {
         p_name += cid_str_size;
@@ -212,13 +213,17 @@ static int vmdk_write_cid(BlockDriverState *bs, uint32_t 
cid)
     BDRVVmdkState *s = bs->opaque;
     int ret;
 
-    memset(desc, 0, sizeof(desc));
     ret = bdrv_pread(bs->file, s->desc_offset, desc, DESC_SIZE);
     if (ret < 0) {
         return ret;
     }
 
+    desc[DESC_SIZE - 1] = '\0';
     tmp_str = strstr(desc, "parentCID");
+    if (tmp_str == NULL) {
+        return -EINVAL;
+    }
+
     pstrcpy(tmp_desc, sizeof(tmp_desc), tmp_str);
     p_name = strstr(desc, "CID");
     if (p_name != NULL) {
-- 
1.7.7