The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 49ae997f8f0d5e268bbd271c5fd66166ce8287fe # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024072937-scandal-destiny-2a6b@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
49ae997f8f0d ("nilfs2: add missing check for inode numbers on directory entries")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 49ae997f8f0d5e268bbd271c5fd66166ce8287fe Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi konishi.ryusuke@gmail.com Date: Sun, 23 Jun 2024 14:11:34 +0900 Subject: [PATCH] nilfs2: add missing check for inode numbers on directory entries
Syzbot reported that mounting and unmounting a specific pattern of corrupted nilfs2 filesystem images causes a use-after-free of metadata file inodes, which triggers a kernel bug in lru_add_fn().
As Jan Kara pointed out, this is because the link count of a metadata file gets corrupted to 0, and nilfs_evict_inode(), which is called from iput(), tries to delete that inode (ifile inode in this case).
The inconsistency occurs because directories containing the inode numbers of these metadata files that should not be visible in the namespace are read without checking.
Fix this issue by treating the inode numbers of these internal files as errors in the sanity check helper when reading directory folios/pages.
Also thanks to Hillf Danton and Matthew Wilcox for their initial mm-layer analysis.
Link: https://lkml.kernel.org/r/20240623051135.4180-3-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Reported-by: syzbot+d79afb004be235636ee8@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d79afb004be235636ee8 Reported-by: Jan Kara jack@suse.cz Closes: https://lkml.kernel.org/r/20240617075758.wewhukbrjod5fp5o@quack3 Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: Hillf Danton hdanton@sina.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c index 52e50b1b7f22..dddfa604491a 100644 --- a/fs/nilfs2/dir.c +++ b/fs/nilfs2/dir.c @@ -135,6 +135,9 @@ static bool nilfs_check_folio(struct folio *folio, char *kaddr) goto Enamelen; if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)) goto Espan; + if (unlikely(p->inode && + NILFS_PRIVATE_INODE(le64_to_cpu(p->inode)))) + goto Einumber; } if (offs != limit) goto Eend; @@ -160,6 +163,9 @@ static bool nilfs_check_folio(struct folio *folio, char *kaddr) goto bad_entry; Espan: error = "directory entry across blocks"; + goto bad_entry; +Einumber: + error = "disallowed inode number"; bad_entry: nilfs_error(sb, "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%zd, name_len=%d", diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h index 7e39e277c77f..4017f7856440 100644 --- a/fs/nilfs2/nilfs.h +++ b/fs/nilfs2/nilfs.h @@ -121,6 +121,11 @@ enum { ((ino) >= NILFS_FIRST_INO(sb) || \ ((ino) < NILFS_USER_INO && (NILFS_SYS_INO_BITS & BIT(ino))))
+#define NILFS_PRIVATE_INODE(ino) ({ \ + ino_t __ino = (ino); \ + ((__ino) < NILFS_USER_INO && (__ino) != NILFS_ROOT_INO && \ + (__ino) != NILFS_SKETCH_INO); }) + /** * struct nilfs_transaction_info: context information for synchronization * @ti_magic: Magic number