From: Jan Kara jack@suse.cz
commit 11c514a99bb960941535134f0587102855e8ddee upstream.
Perform basic sanity checks of quota headers to avoid kernel crashes on corrupted quota files.
CC: stable@vger.kernel.org Reported-by: syzbot+f816042a7ae2225f25ba@syzkaller.appspotmail.com Reviewed-by: Andreas Dilger adilger@dilger.ca Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/quota/quota_v2.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
--- a/fs/quota/quota_v2.c +++ b/fs/quota/quota_v2.c @@ -159,6 +159,25 @@ static int v2_read_file_info(struct supe qinfo->dqi_entry_size = sizeof(struct v2r1_disk_dqblk); qinfo->dqi_ops = &v2r1_qtree_ops; } + ret = -EUCLEAN; + /* Some sanity checks of the read headers... */ + if ((loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits > + i_size_read(sb_dqopt(sb)->files[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; + } + 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; + } + 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; + } ret = 0; out: up_read(&dqopt->dqio_sem);