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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 11/21] proc: Add superblock config support to procfs [ver #3] From: David Howells To: mszeredi@redhat.com, viro@zeniv.linux.org.uk, jlayton@redhat.com Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Date: Mon, 15 May 2017 16:19:48 +0100 Message-ID: <149486158822.23956.11177118518984651590.stgit@warthog.procyon.org.uk> In-Reply-To: <149486147335.23956.2504187638938281431.stgit@warthog.procyon.org.uk> References: <149486147335.23956.2504187638938281431.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 15 May 2017 15:19:50 +0000 (UTC) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add superblock config support to procfs. Signed-off-by: David Howells --- fs/proc/inode.c | 2 - fs/proc/internal.h | 2 - fs/proc/root.c | 166 +++++++++++++++++++++++++++++++++------------------- 3 files changed, 108 insertions(+), 62 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/fs/proc/inode.c b/fs/proc/inode.c index a4bf66af0ba9..304e5c36b7ba 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -118,7 +118,7 @@ const struct super_operations proc_sops = { .drop_inode = generic_delete_inode, .evict_inode = proc_evict_inode, .statfs = simple_statfs, - .remount_fs = proc_remount, + .remount_fs_sc = proc_remount, .show_options = proc_show_options, }; diff --git a/fs/proc/internal.h b/fs/proc/internal.h index b681533f59dd..4546372c2d13 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -262,7 +262,7 @@ static inline void proc_tty_init(void) {} extern struct proc_dir_entry proc_root; extern void proc_self_init(void); -extern int proc_remount(struct super_block *, int *, char *); +extern int proc_remount(struct super_block *, struct sb_config *); /* * task_[no]mmu.c diff --git a/fs/proc/root.c b/fs/proc/root.c index ee1937b37370..da5757d1c518 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -24,9 +24,18 @@ #include #include #include +#include #include "internal.h" +struct proc_sb_config { + struct sb_config sc; + struct pid_namespace *pid_ns; + unsigned long mask; + int hidepid; + int gid; +}; + enum { Opt_gid, Opt_hidepid, Opt_err, }; @@ -37,56 +46,60 @@ static const match_table_t tokens = { {Opt_err, NULL}, }; -static int proc_parse_options(char *options, struct pid_namespace *pid) +static int proc_parse_mount_option(struct sb_config *sc, char *p) { - char *p; + struct proc_sb_config *cfg = container_of(sc, struct proc_sb_config, sc); substring_t args[MAX_OPT_ARGS]; - int option; - - if (!options) - return 1; - - while ((p = strsep(&options, ",")) != NULL) { - int token; - if (!*p) - continue; - - args[0].to = args[0].from = NULL; - token = match_token(p, tokens, args); - switch (token) { - case Opt_gid: - if (match_int(&args[0], &option)) - return 0; - pid->pid_gid = make_kgid(current_user_ns(), option); - break; - case Opt_hidepid: - if (match_int(&args[0], &option)) - return 0; - if (option < HIDEPID_OFF || - option > HIDEPID_INVISIBLE) { - pr_err("proc: hidepid value must be between 0 and 2.\n"); - return 0; - } - pid->hide_pid = option; - break; - default: - pr_err("proc: unrecognized mount option \"%s\" " - "or missing value\n", p); - return 0; + int token; + + args[0].to = args[0].from = NULL; + token = match_token(p, tokens, args); + switch (token) { + case Opt_gid: + if (match_int(&args[0], &cfg->gid)) + return sb_cfg_inval(sc, "procfs: Unparseable gid= argument"); + break; + + case Opt_hidepid: + if (match_int(&args[0], &cfg->hidepid)) + return sb_cfg_inval(sc, "procfs: Unparseable hidepid= argument"); + if (cfg->hidepid < HIDEPID_OFF || + cfg->hidepid > HIDEPID_INVISIBLE) { + pr_err("proc: hidepid value must be between 0 and 2.\n"); + return sb_cfg_inval(sc, "procfs: Invalid hidepid= argument"); } + break; + + default: + pr_err("proc: unrecognized mount option \"%s\" " + "or missing value\n", p); + return sb_cfg_inval(sc, "procfs: Invalid mount option or missing value"); } - return 1; + cfg->mask |= 1 << token; + return 0; +} + +static void proc_set_options(struct super_block *s, + struct sb_config *sc, + struct pid_namespace *pid_ns, + struct user_namespace *user_ns) +{ + struct proc_sb_config *cfg = container_of(sc, struct proc_sb_config, sc); + + if (cfg->mask & (1 << Opt_gid)) + pid_ns->pid_gid = make_kgid(user_ns, cfg->gid); + if (cfg->mask & (1 << Opt_hidepid)) + pid_ns->hide_pid = cfg->hidepid; } -static int proc_fill_super(struct super_block *s, void *data, int silent) +static int proc_fill_super(struct super_block *s, struct sb_config *sc) { - struct pid_namespace *ns = get_pid_ns(s->s_fs_info); + struct pid_namespace *pid_ns = get_pid_ns(s->s_fs_info); struct inode *root_inode; int ret; - if (!proc_parse_options(data, ns)) - return -EINVAL; + proc_set_options(s, sc, pid_ns, current_user_ns()); /* User space would break if executables or devices appear on proc */ s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV; @@ -103,7 +116,7 @@ static int proc_fill_super(struct super_block *s, void *data, int silent) * top of it */ s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; - + pde_get(&proc_root); root_inode = proc_get_inode(s, &proc_root); if (!root_inode) { @@ -124,27 +137,45 @@ static int proc_fill_super(struct super_block *s, void *data, int silent) return proc_setup_thread_self(s); } -int proc_remount(struct super_block *sb, int *flags, char *data) +int proc_remount(struct super_block *sb, struct sb_config *sc) { struct pid_namespace *pid = sb->s_fs_info; sync_filesystem(sb); - return !proc_parse_options(data, pid); + + if (sc) + proc_set_options(sb, sc, pid, current_user_ns()); + return 0; } -static struct dentry *proc_mount(struct file_system_type *fs_type, - int flags, const char *dev_name, void *data) +static struct dentry *proc_mount(struct sb_config *sc) { - struct pid_namespace *ns; + struct proc_sb_config *cfg = container_of(sc, struct proc_sb_config, sc); - if (flags & MS_KERNMOUNT) { - ns = data; - data = NULL; - } else { - ns = task_active_pid_ns(current); - } + return mount_ns_sc(sc, proc_fill_super, cfg->pid_ns); +} - return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super); +static void proc_sb_config_free(struct sb_config *sc) +{ + struct proc_sb_config *cfg = container_of(sc, struct proc_sb_config, sc); + + if (cfg->pid_ns) + put_pid_ns(cfg->pid_ns); +} + +static const struct sb_config_operations proc_sb_config_ops = { + .free = proc_sb_config_free, + .parse_option = proc_parse_mount_option, + .mount = proc_mount, +}; + +static int proc_init_sb_config(struct sb_config *sc, struct super_block *src_sb) +{ + struct proc_sb_config *cfg = container_of(sc, struct proc_sb_config, sc); + + cfg->pid_ns = get_pid_ns(task_active_pid_ns(current)); + cfg->sc.ops = &proc_sb_config_ops; + return 0; } static void proc_kill_sb(struct super_block *sb) @@ -162,7 +193,8 @@ static void proc_kill_sb(struct super_block *sb) static struct file_system_type proc_fs_type = { .name = "proc", - .mount = proc_mount, + .sb_config_size = sizeof(struct proc_sb_config), + .init_sb_config = proc_init_sb_config, .kill_sb = proc_kill_sb, .fs_flags = FS_USERNS_MOUNT, }; @@ -210,7 +242,7 @@ static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentr { if (!proc_pid_lookup(dir, dentry, flags)) return NULL; - + return proc_lookup(dir, dentry, flags); } @@ -249,12 +281,12 @@ static const struct inode_operations proc_root_inode_operations = { * This is the root "inode" in the /proc tree.. */ struct proc_dir_entry proc_root = { - .low_ino = PROC_ROOT_INO, - .namelen = 5, - .mode = S_IFDIR | S_IRUGO | S_IXUGO, - .nlink = 2, + .low_ino = PROC_ROOT_INO, + .namelen = 5, + .mode = S_IFDIR | S_IRUGO | S_IXUGO, + .nlink = 2, .count = ATOMIC_INIT(1), - .proc_iops = &proc_root_inode_operations, + .proc_iops = &proc_root_inode_operations, .proc_fops = &proc_root_operations, .parent = &proc_root, .subdir = RB_ROOT, @@ -263,9 +295,23 @@ struct proc_dir_entry proc_root = { int pid_ns_prepare_proc(struct pid_namespace *ns) { + struct proc_sb_config *cfg; + struct sb_config *sc; struct vfsmount *mnt; - mnt = kern_mount_data(&proc_fs_type, ns); + sc = __vfs_new_sb_config(&proc_fs_type, NULL, 0, SB_CONFIG_FOR_NEW); + if (IS_ERR(sc)) + return PTR_ERR(sc); + + cfg = container_of(sc, struct proc_sb_config, sc); + if (cfg->pid_ns != ns) { + put_pid_ns(cfg->pid_ns); + get_pid_ns(ns); + cfg->pid_ns = ns; + } + + mnt = kern_mount_data_sc(sc); + put_sb_config(sc); if (IS_ERR(mnt)) return PTR_ERR(mnt);