ext4: Avoid underflow in ext4_trim_fs()

commit 5de35e8d5c02d271c20e18337e01bc20e6ef472e upstream.

Currently if len argument in ext4_trim_fs() is smaller than one block,
the 'end' variable underflow. Avoid that by returning EINVAL if len is
smaller than file system block.

Also remove useless unlikely().

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 6b0a57eafb5387bb3c4c9b7016f2a8ffb74508af..e77c4fe665a070f5cc1ad2992f52c101e0643915 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4984,8 +4984,9 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
        end = start + (range->len >> sb->s_blocksize_bits) - 1;
        minlen = range->minlen >> sb->s_blocksize_bits;
 
-       if (unlikely(minlen > EXT4_CLUSTERS_PER_GROUP(sb)) ||
-           unlikely(start >= max_blks))
+       if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
+           start >= max_blks ||
+           range->len < sb->s_blocksize)
                return -EINVAL;
        if (end >= max_blks)
                end = max_blks - 1;