[PULL 09/17] block/vpc: Make vpc_open() read the full dynamic header

[Kevin Wolf]

From: Markus Armbruster <armbru@redhat.com>

The dynamic header's size is 1024 bytes.

vpc_open() reads only the 512 bytes of the dynamic header into buf[].
Works, because it doesn't actually access the second half.  However, a
colleague told me that GCC 11 warns:

    ../block/vpc.c:358:51: error: array subscript 'struct VHDDynDiskHeader[0]' 
is partly outside array bounds of 'uint8_t[512]' [-Werror=array-bounds]

Clean up to read the full header.

Rename buf[] to dyndisk_header_buf[] while there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201217162003.1102738-2-armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/vpc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/block/vpc.c b/block/vpc.c
index 1ab55f9287..2fcf3f6283 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -220,7 +220,7 @@ static int vpc_open(BlockDriverState *bs, QDict *options, 
int flags,
     QemuOpts *opts = NULL;
     Error *local_err = NULL;
     bool use_chs;
-    uint8_t buf[HEADER_SIZE];
+    uint8_t dyndisk_header_buf[1024];
     uint32_t checksum;
     uint64_t computed_size;
     uint64_t pagetable_size;
@@ -340,14 +340,14 @@ static int vpc_open(BlockDriverState *bs, QDict *options, 
int flags,
     }
 
     if (disk_type == VHD_DYNAMIC) {
-        ret = bdrv_pread(bs->file, be64_to_cpu(footer->data_offset), buf,
-                         HEADER_SIZE);
+        ret = bdrv_pread(bs->file, be64_to_cpu(footer->data_offset),
+                         dyndisk_header_buf, 1024);
         if (ret < 0) {
             error_setg(errp, "Error reading dynamic VHD header");
             goto fail;
         }
 
-        dyndisk_header = (VHDDynDiskHeader *) buf;
+        dyndisk_header = (VHDDynDiskHeader *)dyndisk_header_buf;
 
         if (strncmp(dyndisk_header->magic, "cxsparse", 8)) {
             error_setg(errp, "Invalid header magic");
-- 
2.29.2