This is a note to let you know that I've just added the patch titled
nilfs2: fix use-after-free bug of struct nilfs_root
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nilfs2-fix-use-after-free-bug-of-struct-nilfs_root.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d325dc6eb763c10f591c239550b8c7e5466a5d09 Mon Sep 17 00:00:00 2001
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Date: Tue, 4 Oct 2022 00:05:19 +0900
Subject: nilfs2: fix use-after-free bug of struct nilfs_root
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
commit d325dc6eb763c10f591c239550b8c7e5466a5d09 upstream.
If the beginning of the inode bitmap area is corrupted on disk, an inode
with the same inode number as the root inode can be allocated and fail
soon after. In this case, the subsequent call to nilfs_clear_inode() on
that bogus root inode will wrongly decrement the reference counter of
struct nilfs_root, and this will erroneously free struct nilfs_root,
causing kernel oopses.
This fixes the problem by changing nilfs_new_inode() to skip reserved
inode numbers while repairing the inode bitmap.
Link: https://lkml.kernel.org/r/20221003150519.39789-1-konishi.ryusuke@xxxxxxxxx
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Reported-by: syzbot+b8c672b0e22615c80fe0@xxxxxxxxxxxxxxxxxxxxxxxxx
Reported-by: Khalid Masum <khalid.masum.92@xxxxxxxxx>
Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/inode.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -328,6 +328,7 @@ struct inode *nilfs_new_inode(struct ino
struct inode *inode;
struct nilfs_inode_info *ii;
struct nilfs_root *root;
+ struct buffer_head *bh;
int err = -ENOMEM;
ino_t ino;
@@ -343,11 +344,25 @@ struct inode *nilfs_new_inode(struct ino
ii->i_state = BIT(NILFS_I_NEW);
ii->i_root = root;
- err = nilfs_ifile_create_inode(root->ifile, &ino, &ii->i_bh);
+ err = nilfs_ifile_create_inode(root->ifile, &ino, &bh);
if (unlikely(err))
goto failed_ifile_create_inode;
/* reference count of i_bh inherits from nilfs_mdt_read_block() */
+ if (unlikely(ino < NILFS_USER_INO)) {
+ nilfs_warn(sb,
+ "inode bitmap is inconsistent for reserved inodes");
+ do {
+ brelse(bh);
+ err = nilfs_ifile_create_inode(root->ifile, &ino, &bh);
+ if (unlikely(err))
+ goto failed_ifile_create_inode;
+ } while (ino < NILFS_USER_INO);
+
+ nilfs_info(sb, "repaired inode bitmap for reserved inodes");
+ }
+ ii->i_bh = bh;
+
atomic64_inc(&root->inodes_count);
inode_init_owner(&init_user_ns, inode, dir, mode);
inode->i_ino = ino;
Patches currently in stable-queue which might be from konishi.ryusuke@xxxxxxxxx are
queue-6.0/nilfs2-fix-leak-of-nilfs_root-in-case-of-writer-thread-creation-failure.patch
queue-6.0/nilfs2-replace-warn_ons-by-nilfs_error-for-checkpoint-acquisition-failure.patch
queue-6.0/nilfs2-fix-use-after-free-bug-of-struct-nilfs_root.patch
queue-6.0/nilfs2-fix-null-pointer-dereference-at-nilfs_bmap_lookup_at_level.patch
