Ryusuke Konishi (2): nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput nilfs2: fix missing cleanup on rollforward recovery error
fs/nilfs2/inode.c | 8 ++++++++ fs/nilfs2/recovery.c | 35 +++++++++++++++++++++++++++++++++-- fs/nilfs2/segment.c | 2 ++ fs/nilfs2/the_nilfs.h | 2 ++ 4 files changed, 45 insertions(+), 2 deletions(-)
-- 2.25.1
From: Ryusuke Konishi konishi.ryusuke@gmail.com
stable inclusion from stable-v4.19.292 commit a3c3b4cbf9b8554120fb230e6516e980c6277487 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IARYB6 CVE: CVE-2024-46781
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit f8654743a0e6909dc634cbfad6db6816f10f3399 upstream.
During unmount process of nilfs2, nothing holds nilfs_root structure after nilfs2 detaches its writer in nilfs_detach_log_writer(). Previously, nilfs_evict_inode() could cause use-after-free read for nilfs_root if inodes are left in "garbage_list" and released by nilfs_dispose_list at the end of nilfs_detach_log_writer(), and this bug was fixed by commit 9b5a04ac3ad9 ("nilfs2: fix use-after-free bug of nilfs_root in nilfs_evict_inode()").
However, it turned out that there is another possibility of UAF in the call path where mark_inode_dirty_sync() is called from iput():
nilfs_detach_log_writer() nilfs_dispose_list() iput() mark_inode_dirty_sync() __mark_inode_dirty() nilfs_dirty_inode() __nilfs_mark_inode_dirty() nilfs_load_inode_block() --> causes UAF of nilfs_root struct
This can happen after commit 0ae45f63d4ef ("vfs: add support for a lazytime mount option"), which changed iput() to call mark_inode_dirty_sync() on its final reference if i_state has I_DIRTY_TIME flag and i_nlink is non-zero.
This issue appears after commit 28a65b49eb53 ("nilfs2: do not write dirty data after degenerating to read-only") when using the syzbot reproducer, but the issue has potentially existed before.
Fix this issue by adding a "purging flag" to the nilfs structure, setting that flag while disposing the "garbage_list" and checking it in __nilfs_mark_inode_dirty().
Unlike commit 9b5a04ac3ad9 ("nilfs2: fix use-after-free bug of nilfs_root in nilfs_evict_inode()"), this patch does not rely on ns_writer to determine whether to skip operations, so as not to break recovery on mount. The nilfs_salvage_orphan_logs routine dirties the buffer of salvaged data before attaching the log writer, so changing __nilfs_mark_inode_dirty() to skip the operation when ns_writer is NULL will cause recovery write to fail. The purpose of using the cleanup-only flag is to allow for narrowing of such conditions.
Link: https://lkml.kernel.org/r/20230728191318.33047-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Reported-by: syzbot+74db8b3087f293d3a13a@syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/000000000000b4e906060113fd63@google.com Fixes: 0ae45f63d4ef ("vfs: add support for a lazytime mount option") Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org # 4.0+ Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zeng Heng zengheng4@huawei.com --- fs/nilfs2/inode.c | 8 ++++++++ fs/nilfs2/segment.c | 2 ++ fs/nilfs2/the_nilfs.h | 2 ++ 3 files changed, 12 insertions(+)
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c index fb594edc0837..48acbf3a0252 100644 --- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -1085,9 +1085,17 @@ int nilfs_set_file_dirty(struct inode *inode, unsigned int nr_dirty)
int __nilfs_mark_inode_dirty(struct inode *inode, int flags) { + struct the_nilfs *nilfs = inode->i_sb->s_fs_info; struct buffer_head *ibh; int err;
+ /* + * Do not dirty inodes after the log writer has been detached + * and its nilfs_root struct has been freed. + */ + if (unlikely(nilfs_purging(nilfs))) + return 0; + err = nilfs_load_inode_block(inode, &ibh); if (unlikely(err)) { nilfs_warn(inode->i_sb, diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c index a8266c0a35b1..98cc37d2a72a 100644 --- a/fs/nilfs2/segment.c +++ b/fs/nilfs2/segment.c @@ -2862,6 +2862,7 @@ void nilfs_detach_log_writer(struct super_block *sb) nilfs_segctor_destroy(nilfs->ns_writer); nilfs->ns_writer = NULL; } + set_nilfs_purging(nilfs);
/* Force to free the list of dirty files */ spin_lock(&nilfs->ns_inode_lock); @@ -2874,4 +2875,5 @@ void nilfs_detach_log_writer(struct super_block *sb) up_write(&nilfs->ns_segctor_sem);
nilfs_dispose_list(nilfs, &garbage_list, 1); + clear_nilfs_purging(nilfs); } diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index e9408f501e8b..c1eea04052e6 100644 --- a/fs/nilfs2/the_nilfs.h +++ b/fs/nilfs2/the_nilfs.h @@ -29,6 +29,7 @@ enum { THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ THE_NILFS_GC_RUNNING, /* gc process is running */ THE_NILFS_SB_DIRTY, /* super block is dirty */ + THE_NILFS_PURGING, /* disposing dirty files for cleanup */ };
/** @@ -208,6 +209,7 @@ THE_NILFS_FNS(INIT, init) THE_NILFS_FNS(DISCONTINUED, discontinued) THE_NILFS_FNS(GC_RUNNING, gc_running) THE_NILFS_FNS(SB_DIRTY, sb_dirty) +THE_NILFS_FNS(PURGING, purging)
/* * Mount option operations
From: Ryusuke Konishi konishi.ryusuke@gmail.com
stable inclusion from stable-v4.19.322 commit 35a9a7a7d94662146396199b0cfd95f9517cdd14 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IARYB6 CVE: CVE-2024-46781
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 5787fcaab9eb5930f5378d6a1dd03d916d146622 upstream.
In an error injection test of a routine for mount-time recovery, KASAN found a use-after-free bug.
It turned out that if data recovery was performed using partial logs created by dsync writes, but an error occurred before starting the log writer to create a recovered checkpoint, the inodes whose data had been recovered were left in the ns_dirty_files list of the nilfs object and were not freed.
Fix this issue by cleaning up inodes that have read the recovery data if the recovery routine fails midway before the log writer starts.
Link: https://lkml.kernel.org/r/20240810065242.3701-1-konishi.ryusuke@gmail.com Fixes: 0f3e1c7f23f8 ("nilfs2: recovery functions") Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zeng Heng zengheng4@huawei.com Conflicts: fs/nilfs2/recovery.c [Context changed and no logic confilct.] --- fs/nilfs2/recovery.c | 35 +++++++++++++++++++++++++++++++++-- 1 file changed, 33 insertions(+), 2 deletions(-)
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c index 188b8cc52e2b..33c4a97519de 100644 --- a/fs/nilfs2/recovery.c +++ b/fs/nilfs2/recovery.c @@ -708,6 +708,33 @@ static void nilfs_finish_roll_forward(struct the_nilfs *nilfs, brelse(bh); }
+/** + * nilfs_abort_roll_forward - cleaning up after a failed rollforward recovery + * @nilfs: nilfs object + */ +static void nilfs_abort_roll_forward(struct the_nilfs *nilfs) +{ + struct nilfs_inode_info *ii, *n; + LIST_HEAD(head); + + /* Abandon inodes that have read recovery data */ + spin_lock(&nilfs->ns_inode_lock); + list_splice_init(&nilfs->ns_dirty_files, &head); + spin_unlock(&nilfs->ns_inode_lock); + if (list_empty(&head)) + return; + + set_nilfs_purging(nilfs); + list_for_each_entry_safe(ii, n, &head, i_dirty) { + spin_lock(&nilfs->ns_inode_lock); + list_del_init(&ii->i_dirty); + spin_unlock(&nilfs->ns_inode_lock); + + iput(&ii->vfs_inode); + } + clear_nilfs_purging(nilfs); +} + /** * nilfs_salvage_orphan_logs - salvage logs written after the latest checkpoint * @nilfs: nilfs object @@ -766,15 +793,19 @@ int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs, if (unlikely(err)) { nilfs_err(sb, "error %d writing segment for recovery", err); - goto failed; + goto put_root; }
nilfs_finish_roll_forward(nilfs, ri); }
- failed: +put_root: nilfs_put_root(root); return err; + +failed: + nilfs_abort_roll_forward(nilfs); + goto put_root; }
/**
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