diff options
| author |   Miklos Szeredi <mszeredi@redhat.com> | 2020-05-14 16:44:23 +0200 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2020-05-14 16:44:23 +0200 |
| commit | a3c751a50fe6bbe50eb7622a14b18b361804ee0c (patch) | |
| tree | c06d4a05f89fea5d5ea3f4729ab6748140bbb77a /include/linux/device_cgroup.h | |
| parent | Linux 5.7-rc4 (diff) | |
| download | wireguard-linux-a3c751a50fe6bbe50eb7622a14b18b361804ee0c.tar.xz wireguard-linux-a3c751a50fe6bbe50eb7622a14b18b361804ee0c.zip | |
vfs: allow unprivileged whiteout creation
Whiteouts, unlike real device node should not require privileges to create.
The general concern with device nodes is that opening them can have side
effects. The kernel already avoids zero major (see
Documentation/admin-guide/devices.txt). To be on the safe side the patch
explicitly forbids registering a char device with 0/0 number (see
cdev_add()).
This guarantees that a non-O_PATH open on a whiteout will fail with ENODEV;
i.e. it won't have any side effect.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'include/linux/device_cgroup.h')
| -rw-r--r-- | include/linux/device_cgroup.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/device_cgroup.h b/include/linux/device_cgroup.h index fa35b52e0002..57e63bd63370 100644 --- a/include/linux/device_cgroup.h +++ b/include/linux/device_cgroup.h @@ -51,6 +51,9 @@ static inline int devcgroup_inode_mknod(int mode, dev_t dev) if (!S_ISBLK(mode) && !S_ISCHR(mode)) return 0; + if (S_ISCHR(mode) && dev == WHITEOUT_DEV) + return 0; + if (S_ISBLK(mode)) type = DEVCG_DEV_BLOCK; else |