[Qemu-block] [PATCH] qcow2: Prevent backing file names longer than 1023

[Max Reitz]

We reject backing file names with a length of more than 1023 characters
when opening a qcow2 file, so we should not produce such files
ourselves.

Cc: address@hidden
Signed-off-by: Max Reitz <address@hidden>
---
 block/qcow2.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/block/qcow2.c b/block/qcow2.c
index 056525c..011a0ae 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1957,6 +1957,11 @@ int qcow2_update_header(BlockDriverState *bs)
     if (s->image_backing_file) {
         size_t backing_file_len = strlen(s->image_backing_file);
 
+        if (backing_file_len > 1023) {
+            ret = -EINVAL;
+            goto fail;
+        }
+
         if (buflen < backing_file_len) {
             ret = -ENOSPC;
             goto fail;
-- 
2.8.0