quota: Fix memory leak when handling corrupted quota file

When checking corrupted quota file we can bail out and leak allocated
info structure. Properly free info structure on error return.

Reported-by: syzbot+77779c9b52ab78154b08@syzkaller.appspotmail.com
Fixes: 11c514a99bb9 ("quota: Sanity-check quota file headers on load")
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/quota/quota_v2.c b/fs/quota/quota_v2.c
index c21106557a37e225e2b24cd3ead3845d047decaf..b1467f3921c28fc644edce213c390382668b4856 100644 (file)
--- a/fs/quota/quota_v2.c
+++ b/fs/quota/quota_v2.c
@@ -164,19 +164,24 @@ static int v2_read_file_info(struct super_block *sb, int type)
                quota_error(sb, "Number of blocks too big for quota file size (%llu > %llu).",
                    (loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits,
                    i_size_read(sb_dqopt(sb)->files[type]));
-               goto out;
+               goto out_free;
        }
        if (qinfo->dqi_free_blk >= qinfo->dqi_blocks) {
                quota_error(sb, "Free block number too big (%u >= %u).",
                            qinfo->dqi_free_blk, qinfo->dqi_blocks);
-               goto out;
+               goto out_free;
        }
        if (qinfo->dqi_free_entry >= qinfo->dqi_blocks) {
                quota_error(sb, "Block with free entry too big (%u >= %u).",
                            qinfo->dqi_free_entry, qinfo->dqi_blocks);
-               goto out;
+               goto out_free;
        }
        ret = 0;
+out_free:
+       if (ret) {
+               kfree(info->dqi_priv);
+               info->dqi_priv = NULL;
+       }
 out:
        up_read(&dqopt->dqio_sem);
        return ret;