diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2016-09-14 21:53:38 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-23 12:31:31 +0300 |
| commit | e98d41370392dbc3e94c8802ce4e9eec9efdf92e (patch) | |
| tree | f3aeb2482e3a348fad2376a5f998b880956d9369 | |
| parent | 6bd1d8758db278cb97989a0ebd85059fd948b73b (diff) | |
| download | linux-e98d41370392dbc3e94c8802ce4e9eec9efdf92e.tar.xz | |
devpts: Change the owner of /dev/pts/ptmx to the mounter of /dev/pts
In 99.99% of the cases only root in a user namespace can mount /dev/pts
and in those cases the owner of /dev/pts/ptmx will remain root.root
In the oddball case where someone else has CAP_SYS_ADMIN this code
modifies the /dev/pts mount code to use current_fsuid and current_fsgid
as the values to use when creating the /dev/ptmx inode. As is done
when any other file is created.
This is a code simplification, and it allows running without a root
user entirely.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/devpts/inode.c | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c index 17593d3fcdbe..442d1a7e671b 100644 --- a/fs/devpts/inode.c +++ b/fs/devpts/inode.c @@ -272,13 +272,8 @@ static int mknod_ptmx(struct super_block *sb) struct dentry *root = sb->s_root; struct pts_fs_info *fsi = DEVPTS_SB(sb); struct pts_mount_opts *opts = &fsi->mount_opts; - kuid_t root_uid; - kgid_t root_gid; - - root_uid = make_kuid(current_user_ns(), 0); - root_gid = make_kgid(current_user_ns(), 0); - if (!uid_valid(root_uid) || !gid_valid(root_gid)) - return -EINVAL; + kuid_t ptmx_uid = current_fsuid(); + kgid_t ptmx_gid = current_fsgid(); inode_lock(d_inode(root)); @@ -309,8 +304,8 @@ static int mknod_ptmx(struct super_block *sb) mode = S_IFCHR|opts->ptmxmode; init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2)); - inode->i_uid = root_uid; - inode->i_gid = root_gid; + inode->i_uid = ptmx_uid; + inode->i_gid = ptmx_gid; d_add(dentry, inode); |