fs/nilfs2: fix potential underflow in call to crc32_le

[cascardo/linux.git] / fs / nilfs2 / the_nilfs.c

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 809bd2d..e9fd241 100644 (file)
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -439,7 +439,7 @@ static int nilfs_valid_sb(struct nilfs_super_block *sbp)
        if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
                return 0;
        bytes = le16_to_cpu(sbp->s_bytes);
-       if (bytes > BLOCK_SIZE)
+       if (bytes < sumoff + 4 || bytes > BLOCK_SIZE)
                return 0;
        crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
                       sumoff);