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| author | Eric W. Biederman <ebiederm@xmission.com> | 2017-01-04 17:37:27 +1300 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2017-01-10 13:34:55 +1300 |
| commit | 75422726b0f717d67db3283c2eb5bc14fa2619c5 (patch) | |
| tree | 166111b615cc1e00e809eff6186146e09785c524 | |
| parent | 3895dbf8985f656675b5bde610723a29cbce3fa7 (diff) | |
| download | lwn-75422726b0f717d67db3283c2eb5bc14fa2619c5.tar.gz lwn-75422726b0f717d67db3283c2eb5bc14fa2619c5.zip | |
libfs: Modify mount_pseudo_xattr to be clear it is not a userspace mount
Add MS_KERNMOUNT to the flags that are passed.
Use sget_userns and force &init_user_ns instead of calling sget so that
even if called from a weird context the internal filesystem will be
considered to be in the intial user namespace.
Luis Ressel reported that the the failure to pass MS_KERNMOUNT into
mount_pseudo broke his in development graphics driver that uses the
generic drm infrastructure. I am not certain the deriver was bug
free in it's usage of that infrastructure but since
mount_pseudo_xattr can never be triggered by userspace it is clearer
and less error prone, and less problematic for the code to be explicit.
Reported-by: Luis Ressel <aranea@aixah.de>
Tested-by: Luis Ressel <aranea@aixah.de>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| -rw-r--r-- | fs/libfs.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/libfs.c b/fs/libfs.c index e973cd51f126..28d6f35feed6 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -245,7 +245,8 @@ struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type, char *name, struct inode *root; struct qstr d_name = QSTR_INIT(name, strlen(name)); - s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); + s = sget_userns(fs_type, NULL, set_anon_super, MS_KERNMOUNT|MS_NOUSER, + &init_user_ns, NULL); if (IS_ERR(s)) return ERR_CAST(s); |