From 9845664b9ee47ce7ee7ea93caf47d39a9d4552c4 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Wed, 14 Feb 2024 16:19:24 +0100 Subject: btrfs: dev-replace: properly validate device names There's a syzbot report that device name buffers passed to device replace are not properly checked for string termination which could lead to a read out of bounds in getname_kernel(). Add a helper that validates both source and target device name buffers. For devid as the source initialize the buffer to empty string in case something tries to read it later. This was originally analyzed and fixed in a different way by Edward Adam Davis (see links). Link: https://lore.kernel.org/linux-btrfs/000000000000d1a1d1060cc9c5e7@google.com/ Link: https://lore.kernel.org/linux-btrfs/tencent_44CA0665C9836EF9EEC80CB9E7E206DF5206@qq.com/ CC: stable@vger.kernel.org # 4.19+ CC: Edward Adam Davis Reported-and-tested-by: syzbot+33f23b49ac24f986c9e8@syzkaller.appspotmail.com Reviewed-by: Boris Burkov Signed-off-by: David Sterba --- fs/btrfs/dev-replace.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) (limited to 'fs/btrfs/dev-replace.c') diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index 1502d664c892..79c4293ddf37 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -725,6 +725,23 @@ leave: return ret; } +static int btrfs_check_replace_dev_names(struct btrfs_ioctl_dev_replace_args *args) +{ + if (args->start.srcdevid == 0) { + if (memchr(args->start.srcdev_name, 0, + sizeof(args->start.srcdev_name)) == NULL) + return -ENAMETOOLONG; + } else { + args->start.srcdev_name[0] = 0; + } + + if (memchr(args->start.tgtdev_name, 0, + sizeof(args->start.tgtdev_name)) == NULL) + return -ENAMETOOLONG; + + return 0; +} + int btrfs_dev_replace_by_ioctl(struct btrfs_fs_info *fs_info, struct btrfs_ioctl_dev_replace_args *args) { @@ -737,10 +754,9 @@ int btrfs_dev_replace_by_ioctl(struct btrfs_fs_info *fs_info, default: return -EINVAL; } - - if ((args->start.srcdevid == 0 && args->start.srcdev_name[0] == '\0') || - args->start.tgtdev_name[0] == '\0') - return -EINVAL; + ret = btrfs_check_replace_dev_names(args); + if (ret < 0) + return ret; ret = btrfs_dev_replace_start(fs_info, args->start.tgtdev_name, args->start.srcdevid, -- cgit From 9ae061cf2a46980b37cec1e56a372603682b2741 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 23 Jan 2024 14:26:36 +0100 Subject: btrfs: port device access to file Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-19-adbd023e19cc@kernel.org Reviewed-by: Jan Kara Signed-off-by: Christian Brauner --- fs/btrfs/dev-replace.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'fs/btrfs/dev-replace.c') diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index 1502d664c892..2eb11fe4bd05 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -246,7 +246,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, { struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; struct btrfs_device *device; - struct bdev_handle *bdev_handle; + struct file *bdev_file; struct block_device *bdev; u64 devid = BTRFS_DEV_REPLACE_DEVID; int ret = 0; @@ -257,13 +257,13 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, return -EINVAL; } - bdev_handle = bdev_open_by_path(device_path, BLK_OPEN_WRITE, + bdev_file = bdev_file_open_by_path(device_path, BLK_OPEN_WRITE, fs_info->bdev_holder, NULL); - if (IS_ERR(bdev_handle)) { + if (IS_ERR(bdev_file)) { btrfs_err(fs_info, "target device %s is invalid!", device_path); - return PTR_ERR(bdev_handle); + return PTR_ERR(bdev_file); } - bdev = bdev_handle->bdev; + bdev = file_bdev(bdev_file); if (!btrfs_check_device_zone_type(fs_info, bdev)) { btrfs_err(fs_info, @@ -314,7 +314,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, device->commit_bytes_used = device->bytes_used; device->fs_info = fs_info; device->bdev = bdev; - device->bdev_handle = bdev_handle; + device->bdev_file = bdev_file; set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state); set_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state); device->dev_stats_valid = 1; @@ -335,7 +335,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, return 0; error: - bdev_release(bdev_handle); + fput(bdev_file); return ret; } -- cgit