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| author | Dongliang Mu <mudongliangabcd@gmail.com> | 2022-03-03 22:40:27 +0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2022-03-14 13:13:54 +0100 |
| commit | 79c9234ba596e903907de20573fd4bcc85315b06 (patch) | |
| tree | 4421b9c319003e382e7a9b437065d41bfacc3797 /fs/btrfs | |
| parent | bf7bd725b022cca0195aa81a378a82b1e731a4a3 (diff) | |
| download | linux-79c9234ba596e903907de20573fd4bcc85315b06.tar.bz2 | |
btrfs: don't access possibly stale fs_info data in device_list_add
Syzbot reported a possible use-after-free in printing information
in device_list_add.
Very similar with the bug fixed by commit 0697d9a61099 ("btrfs: don't
access possibly stale fs_info data for printing duplicate device"),
but this time the use occurs in btrfs_info_in_rcu.
Call Trace:
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
btrfs_printk+0x395/0x425 fs/btrfs/super.c:244
device_list_add.cold+0xd7/0x2ed fs/btrfs/volumes.c:957
btrfs_scan_one_device+0x4c7/0x5c0 fs/btrfs/volumes.c:1387
btrfs_control_ioctl+0x12a/0x2d0 fs/btrfs/super.c:2409
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fix this by modifying device->fs_info to NULL too.
Reported-and-tested-by: syzbot+82650a4e0ed38f218363@syzkaller.appspotmail.com
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/volumes.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 5e3e13d4940b..1be7cb2f955f 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -921,16 +921,15 @@ static noinline struct btrfs_device *device_list_add(const char *path, /* * We are going to replace the device path for a given devid, * make sure it's the same device if the device is mounted + * + * NOTE: the device->fs_info may not be reliable here so pass + * in a NULL to message helpers instead. This avoids a possible + * use-after-free when the fs_info and fs_info->sb are already + * torn down. */ if (device->bdev) { if (device->devt != path_devt) { mutex_unlock(&fs_devices->device_list_mutex); - /* - * device->fs_info may not be reliable here, so - * pass in a NULL instead. This avoids a - * possible use-after-free when the fs_info and - * fs_info->sb are already torn down. - */ btrfs_warn_in_rcu(NULL, "duplicate device %s devid %llu generation %llu scanned by %s (%d)", path, devid, found_transid, @@ -938,7 +937,7 @@ static noinline struct btrfs_device *device_list_add(const char *path, task_pid_nr(current)); return ERR_PTR(-EEXIST); } - btrfs_info_in_rcu(device->fs_info, + btrfs_info_in_rcu(NULL, "devid %llu device path %s changed to %s scanned by %s (%d)", devid, rcu_str_deref(device->name), path, current->comm, |