diff options
| author | Sheng Yong <shengyong1@xiaomi.com> | 2025-05-15 09:48:37 +0800 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2025-05-15 11:20:25 +0800 |
| commit | 9748f2f54f66743ac77275c34886a9f890e18409 (patch) | |
| tree | fe21ca027af04eb631444e00d25d41b65cce13fd | |
| parent | 510de8363f2c3d8e67fa9dfb2366e821382036e0 (diff) | |
erofs: avoid using multiple devices with different type
For multiple devices, both primary and extra devices should be the
same type. `erofs_init_device` has already guaranteed that if the
primary is a file-backed device, extra devices should also be
regular files.
However, if the primary is a block device while the extra device
is a file-backed device, `erofs_init_device` will get an ENOTBLK,
which is not treated as an error in `erofs_fc_get_tree`, and that
leads to an UAF:
erofs_fc_get_tree
get_tree_bdev_flags(erofs_fc_fill_super)
erofs_read_superblock
erofs_init_device // sbi->dif0 is not inited yet,
// return -ENOTBLK
deactivate_locked_super
free(sbi)
if (err is -ENOTBLK)
sbi->dif0.file = filp_open() // sbi UAF
So if -ENOTBLK is hitted in `erofs_init_device`, it means the
primary device must be a block device, and the extra device
is not a block device. The error can be converted to -EINVAL.
Fixes: fb176750266a ("erofs: add file-backed mount support")
Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Link: https://lore.kernel.org/r/20250515014837.3315886-1-shengyong1@xiaomi.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
| -rw-r--r-- | fs/erofs/super.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/erofs/super.c b/fs/erofs/super.c index bcb99c3c2594..6e57b9cc6ed2 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -165,8 +165,11 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb, filp_open(dif->path, O_RDONLY | O_LARGEFILE, 0) : bdev_file_open_by_path(dif->path, BLK_OPEN_READ, sb->s_type, NULL); - if (IS_ERR(file)) + if (IS_ERR(file)) { + if (file == ERR_PTR(-ENOTBLK)) + return -EINVAL; return PTR_ERR(file); + } if (!erofs_is_fileio_mode(sbi)) { dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file), |