libblkid: (mac) make sure block size is large enough [fuzzing]

Reported-by: Thibault Guittet <tguittet@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libblkid/src/partitions/mac.c b/libblkid/src/partitions/mac.c
index 092d31d322f2cf8863d944d1f6aa4bf4e076be9d..75a558b0a3d52893057b52afc97964731e859f6c 100644 (file)
--- a/libblkid/src/partitions/mac.c
+++ b/libblkid/src/partitions/mac.c
@@ -93,6 +93,8 @@ static int probe_mac_pt(blkid_probe pr,
        }
 
        block_size = be16_to_cpu(md->block_size);
+       if (block_size < sizeof(struct mac_partition))
+               goto nothing;
 
        /* The partition map always begins at physical block 1,
         * the second block on the disk.