libblkid: fix segfault in drdb

Check if blkid_probe_get_buffer() returns NULL to avoid dereferencing
a zero pointer resulting in a segfault.

Signed-off-by: Matthias König <mk@phasorlab.de>

diff --git a/shlibs/blkid/src/superblocks/drbd.c b/shlibs/blkid/src/superblocks/drbd.c
index e0bbb4d669d45b6b6139493f5b7b3a2a5c922d0d..a56486e97984f37134b54a70056ef208ddc36067 100644 (file)
--- a/shlibs/blkid/src/superblocks/drbd.c
+++ b/shlibs/blkid/src/superblocks/drbd.c
@@ -78,7 +78,8 @@ static int probe_drbd(blkid_probe pr, const struct blkid_idmag *mag)
                blkid_probe_get_buffer(pr,
                off,
                sizeof(struct md_on_disk_08));
-
+       if (!md)
+               return -1;
 
        if (be32_to_cpu(md->magic) != DRBD_MD_MAGIC_08)
                return -1;