| Message ID | 20250103131226.1262042-1-sunjunchao2870@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v4,1/2] ocfs2: Check el->l_next_free_rec in ocfs2_get_clusters_nocache | expand |
Hi, On 2025/1/3 21:12, Julian Sun wrote: > Recently syzbot reported a use-after-free issue[1]. > > The root cause of the problem is that the journal > inode recorded in this file system image is corrupted. > The value of "di->id2.i_list.l_next_free_rec" is 8193, > which is greater than the value of "di->id2.i_list.l_count" (19). > > To solve this problem, an additional check should be added > within ocfs2_get_clusters_nocache(). If the check fails, an error will > be returned and the file system will be set to read-only. > > [1]: https://lore.kernel.org/all/67577778.050a0220.a30f1.01bc.GAE@google.com/T/ > > Reported-and-tested-by: syzbot+2313dda4dc4885c93578@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=2313dda4dc4885c93578 > Signed-off-by: Julian Sun <sunjunchao2870@gmail.com> > --- > fs/ocfs2/extent_map.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c > index f7672472fa82..a326c08d9145 100644 > --- a/fs/ocfs2/extent_map.c > +++ b/fs/ocfs2/extent_map.c > @@ -435,6 +435,17 @@ static int ocfs2_get_clusters_nocache(struct inode *inode, > } > } > > + if (le16_to_cpu(el->l_next_free_rec) > le16_to_cpu(el->l_count)) { > + ocfs2_error(inode->i_sb, > + "Inode %lu has bad extent next_free_rec %u count %u in block %llu\n", Inode %lu has an invalid extent (next_free=%u, count=%u) > + inode->i_ino, > + le16_to_cpu(el->l_next_free_rec), > + le16_to_cpu(el->l_count), > + (unsigned long long)eb_bh->b_blocknr); eb_bh may be NULL here, so don't print here. Thanks, Joseph > + ret = -EROFS; > + goto out; > + } > + > i = ocfs2_search_extent_list(el, v_cluster); > if (i == -1) { > /*
diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c index f7672472fa82..a326c08d9145 100644 --- a/fs/ocfs2/extent_map.c +++ b/fs/ocfs2/extent_map.c @@ -435,6 +435,17 @@ static int ocfs2_get_clusters_nocache(struct inode *inode, } } + if (le16_to_cpu(el->l_next_free_rec) > le16_to_cpu(el->l_count)) { + ocfs2_error(inode->i_sb, + "Inode %lu has bad extent next_free_rec %u count %u in block %llu\n", + inode->i_ino, + le16_to_cpu(el->l_next_free_rec), + le16_to_cpu(el->l_count), + (unsigned long long)eb_bh->b_blocknr); + ret = -EROFS; + goto out; + } + i = ocfs2_search_extent_list(el, v_cluster); if (i == -1) { /*
Recently syzbot reported a use-after-free issue[1]. The root cause of the problem is that the journal inode recorded in this file system image is corrupted. The value of "di->id2.i_list.l_next_free_rec" is 8193, which is greater than the value of "di->id2.i_list.l_count" (19). To solve this problem, an additional check should be added within ocfs2_get_clusters_nocache(). If the check fails, an error will be returned and the file system will be set to read-only. [1]: https://lore.kernel.org/all/67577778.050a0220.a30f1.01bc.GAE@google.com/T/ Reported-and-tested-by: syzbot+2313dda4dc4885c93578@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=2313dda4dc4885c93578 Signed-off-by: Julian Sun <sunjunchao2870@gmail.com> --- fs/ocfs2/extent_map.c | 11 +++++++++++ 1 file changed, 11 insertions(+)