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authorJan Kara <jack@suse.cz>2020-11-02 16:16:29 +0100
committerJan Kara <jack@suse.cz>2020-11-03 11:17:00 +0100
commit11c514a99bb960941535134f0587102855e8ddee (patch)
tree86bdfabc4e8225cbe95a97486fcd8b303f7c414b /fs/quota
parentquota: Don't overflow quota file offsets (diff)
downloadlinux-11c514a99bb960941535134f0587102855e8ddee.tar.xz
linux-11c514a99bb960941535134f0587102855e8ddee.zip
quota: Sanity-check quota file headers on load
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>
Diffstat (limited to 'fs/quota')
-rw-r--r--fs/quota/quota_v2.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/fs/quota/quota_v2.c b/fs/quota/quota_v2.c
index e69a2bfdd81c..c21106557a37 100644
--- a/fs/quota/quota_v2.c
+++ b/fs/quota/quota_v2.c
@@ -157,6 +157,25 @@ static int v2_read_file_info(struct super_block *sb, int type)
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);