diff options
Diffstat (limited to 'fs/devpts/inode.c')
| -rw-r--r-- | fs/devpts/inode.c | 46 |
1 files changed, 35 insertions, 11 deletions
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c index 472e6befc54..cfe8466f7fe 100644 --- a/fs/devpts/inode.c +++ b/fs/devpts/inode.c @@ -10,6 +10,8 @@ * * ------------------------------------------------------------------------- */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include <linux/module.h> #include <linux/init.h> #include <linux/fs.h> @@ -148,10 +150,10 @@ static inline struct super_block *pts_sb_from_inode(struct inode *inode) /* * parse_mount_options(): - * Set @opts to mount options specified in @data. If an option is not - * specified in @data, set it to its default value. The exception is - * 'newinstance' option which can only be set/cleared on a mount (i.e. - * cannot be changed during remount). + * Set @opts to mount options specified in @data. If an option is not + * specified in @data, set it to its default value. The exception is + * 'newinstance' option which can only be set/cleared on a mount (i.e. + * cannot be changed during remount). * * Note: @data may be NULL (in which case all options are set to default). */ @@ -225,7 +227,7 @@ static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) break; #endif default: - printk(KERN_ERR "devpts: called with bogus options\n"); + pr_err("called with bogus options\n"); return -EINVAL; } } @@ -243,6 +245,13 @@ 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; mutex_lock(&root->d_inode->i_mutex); @@ -254,7 +263,7 @@ static int mknod_ptmx(struct super_block *sb) dentry = d_alloc_name(root, "ptmx"); if (!dentry) { - printk(KERN_NOTICE "Unable to alloc dentry for ptmx node\n"); + pr_err("Unable to alloc dentry for ptmx node\n"); goto out; } @@ -263,7 +272,7 @@ static int mknod_ptmx(struct super_block *sb) */ inode = new_inode(sb); if (!inode) { - printk(KERN_ERR "Unable to alloc inode for ptmx node\n"); + pr_err("Unable to alloc inode for ptmx node\n"); dput(dentry); goto out; } @@ -273,6 +282,8 @@ 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; d_add(dentry, inode); @@ -294,7 +305,7 @@ static void update_ptmx_mode(struct pts_fs_info *fsi) #else static inline void update_ptmx_mode(struct pts_fs_info *fsi) { - return; + return; } #endif @@ -304,6 +315,7 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data) struct pts_fs_info *fsi = DEVPTS_SB(sb); struct pts_mount_opts *opts = &fsi->mount_opts; + sync_filesystem(sb); err = parse_mount_options(data, PARSE_REMOUNT, opts); /* @@ -323,9 +335,11 @@ static int devpts_show_options(struct seq_file *seq, struct dentry *root) struct pts_mount_opts *opts = &fsi->mount_opts; if (opts->setuid) - seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, opts->uid)); + seq_printf(seq, ",uid=%u", + from_kuid_munged(&init_user_ns, opts->uid)); if (opts->setgid) - seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, opts->gid)); + seq_printf(seq, ",gid=%u", + from_kgid_munged(&init_user_ns, opts->gid)); seq_printf(seq, ",mode=%03o", opts->mode); #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode); @@ -386,7 +400,7 @@ devpts_fill_super(struct super_block *s, void *data, int silent) if (s->s_root) return 0; - printk(KERN_ERR "devpts: get root dentry failed\n"); + pr_err("get root dentry failed\n"); fail: return -ENOMEM; @@ -438,6 +452,12 @@ static struct dentry *devpts_mount(struct file_system_type *fs_type, if (error) return ERR_PTR(error); + /* Require newinstance for all user namespace mounts to ensure + * the mount options are not changed. + */ + if ((current_user_ns() != &init_user_ns) && !opts.newinstance) + return ERR_PTR(-EINVAL); + if (opts.newinstance) s = sget(fs_type, NULL, set_anon_super, flags, NULL); else @@ -483,6 +503,7 @@ static void devpts_kill_sb(struct super_block *sb) { struct pts_fs_info *fsi = DEVPTS_SB(sb); + ida_destroy(&fsi->allocated_ptys); kfree(fsi); kill_litter_super(sb); } @@ -491,6 +512,9 @@ static struct file_system_type devpts_fs_type = { .name = "devpts", .mount = devpts_mount, .kill_sb = devpts_kill_sb, +#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES + .fs_flags = FS_USERNS_MOUNT | FS_USERNS_DEV_MOUNT, +#endif }; /* |