[24/43] proc: Add fs_context support to procfs

Message ID	155059390291.12449.10527077827963704179.stgit@warthog.procyon.org.uk (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-security-module-owner@kernel.org> Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 24/43] proc: Add fs_context support to procfs From: David Howells <dhowells@redhat.com> To: viro@zeniv.linux.org.uk Cc: Alexey Dobriyan <adobriyan@gmail.com>, linux-fsdevel@vger.kernel.org, dhowells@redhat.com, torvalds@linux-foundation.org, ebiederm@xmission.com, linux-security-module@vger.kernel.org Date: Tue, 19 Feb 2019 16:31:42 +0000 Message-ID: <155059390291.12449.10527077827963704179.stgit@warthog.procyon.org.uk> In-Reply-To: <155059366914.12449.4669870128936536848.stgit@warthog.procyon.org.uk> References: <155059366914.12449.4669870128936536848.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk
Series	VFS: Introduce filesystem context \| expand [00/43] VFS: Introduce filesystem context [01/43] fix cgroup_do_mount() handling of failure exits [02/43] cgroup: saner refcounting for cgroup_root [03/43] kill kernfs_pin_sb() [04/43] separate copying and locking mount tree on cross-userns copies [05/43] saner handling of temporary namespaces [06/43] vfs: Introduce fs_context, switch vfs_kern_mount() to it. [07/43] new helpers: vfs_create_mount(), fc_mount() [08/43] teach vfs_get_tree() to handle subtype, switch do_new_mount() to it [09/43] new helper: do_new_mount_fc() [10/43] vfs_get_tree(): evict the call of security_sb_kern_mount() [11/43] convert do_remount_sb() to fs_context [12/43] fs_context flavour for submounts [13/43] introduce fs_context methods [14/43] vfs: Introduce logging functions [15/43] vfs: Add configuration parser helpers [16/43] vfs: Add LSM hooks for the new mount API [17/43] selinux: Implement the new mount API LSM hooks [18/43] smack: Implement filesystem context security hooks [19/43] vfs: Put security flags into the fs_context struct [20/43] vfs: Implement a filesystem superblock creation/configuration context [21/43] convenience helpers: vfs_get_super() and sget_fc() [22/43] introduce cloning of fs_context [23/43] procfs: Move proc_fill_super() to fs/proc/root.c [24/43] proc: Add fs_context support to procfs [25/43] ipc: Convert mqueue fs to fs_context [26/43] cgroup: start switching to fs_context [27/43] cgroup: fold cgroup1_mount() into cgroup1_get_tree() [28/43] cgroup: take options parsing into ->parse_monolithic() [29/43] cgroup1: switch to option-by-option parsing [30/43] cgroup2: switch to option-by-option parsing [31/43] cgroup: stash cgroup_root reference into cgroup_fs_context [32/43] cgroup_do_mount(): massage calling conventions [33/43] cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper [34/43] cgroup: store a reference to cgroup_ns into cgroup_fs_context [35/43] kernfs, sysfs, cgroup, intel_rdt: Support fs_context [36/43] cpuset: Use fs_context [37/43] hugetlbfs: Convert to fs_context [38/43] vfs: Remove kern_mount_data() [39/43] vfs: Provide documentation for new mount API [40/43] vfs: Implement logging through fs_context [41/43] vfs: Add some logging to the core users of the fs_context log [42/43] afs: Add fs_context support [43/43] afs: Use fs_context to pass parameters over automount

diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 17b5261206dd..fc7e38def174 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -127,7 +127,6 @@ const struct super_operations proc_sops = { .drop_inode = generic_delete_inode, .evict_inode = proc_evict_inode, .statfs = simple_statfs, - .remount_fs = proc_remount, .show_options = proc_show_options, }; diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 97157c0410a2..40f905143d39 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -270,7 +270,6 @@ 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 *); /* * task_[no]mmu.c diff --git a/fs/proc/root.c b/fs/proc/root.c index fe4f64b3250b..6927b29ece76 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -19,74 +19,89 @@ #include <linux/module.h> #include <linux/bitops.h> #include <linux/user_namespace.h> +#include <linux/fs_context.h> #include <linux/mount.h> #include <linux/pid_namespace.h> -#include <linux/parser.h> +#include <linux/fs_parser.h> #include <linux/cred.h> #include <linux/magic.h> +#include <linux/slab.h> #include "internal.h" -enum { - Opt_gid, Opt_hidepid, Opt_err, +struct proc_fs_context { + struct pid_namespace *pid_ns; + unsigned int mask; + int hidepid; + int gid; }; -static const match_table_t tokens = { - {Opt_hidepid, "hidepid=%u"}, - {Opt_gid, "gid=%u"}, - {Opt_err, NULL}, +enum proc_param { + Opt_gid, + Opt_hidepid, }; -static int proc_parse_options(char *options, struct pid_namespace *pid) +static const struct fs_parameter_spec proc_param_specs[] = { + fsparam_u32("gid", Opt_gid), + fsparam_u32("hidepid", Opt_hidepid), + {} +}; + +static const struct fs_parameter_description proc_fs_parameters = { + .name = "proc", + .specs = proc_param_specs, +}; + +static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param) { - char *p; - 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; - } + struct proc_fs_context *ctx = fc->fs_private; + struct fs_parse_result result; + int opt; + + opt = fs_parse(fc, &proc_fs_parameters, param, &result); + if (opt < 0) + return opt; + + switch (opt) { + case Opt_gid: + ctx->gid = result.uint_32; + break; + + case Opt_hidepid: + ctx->hidepid = result.uint_32; + if (ctx->hidepid < HIDEPID_OFF || + ctx->hidepid > HIDEPID_INVISIBLE) + return invalf(fc, "proc: hidepid value must be between 0 and 2.\n"); + break; + + default: + return -EINVAL; } - return 1; + ctx->mask |= 1 << opt; + return 0; +} + +static void proc_apply_options(struct super_block *s, + struct fs_context *fc, + struct pid_namespace *pid_ns, + struct user_namespace *user_ns) +{ + struct proc_fs_context *ctx = fc->fs_private; + + if (ctx->mask & (1 << Opt_gid)) + pid_ns->pid_gid = make_kgid(user_ns, ctx->gid); + if (ctx->mask & (1 << Opt_hidepid)) + pid_ns->hide_pid = ctx->hidepid; } -static int proc_fill_super(struct super_block *s, void *data, int silent) +static int proc_fill_super(struct super_block *s, struct fs_context *fc) { - 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_apply_options(s, fc, 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; @@ -127,27 +142,55 @@ 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) +static int proc_reconfigure(struct fs_context *fc) { + struct super_block *sb = fc->root->d_sb; struct pid_namespace *pid = sb->s_fs_info; sync_filesystem(sb); - return !proc_parse_options(data, pid); + + proc_apply_options(sb, fc, 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 int proc_get_tree(struct fs_context *fc) { - struct pid_namespace *ns; + struct proc_fs_context *ctx = fc->fs_private; - if (flags & SB_KERNMOUNT) { - ns = data; - data = NULL; - } else { - ns = task_active_pid_ns(current); - } + put_user_ns(fc->user_ns); + fc->user_ns = get_user_ns(ctx->pid_ns->user_ns); + fc->s_fs_info = ctx->pid_ns; + return vfs_get_super(fc, vfs_get_keyed_super, proc_fill_super); +} + +static void proc_fs_context_free(struct fs_context *fc) +{ + struct proc_fs_context *ctx = fc->fs_private; + + if (ctx->pid_ns) + put_pid_ns(ctx->pid_ns); + kfree(ctx); +} + +static const struct fs_context_operations proc_fs_context_ops = { + .free = proc_fs_context_free, + .parse_param = proc_parse_param, + .get_tree = proc_get_tree, + .reconfigure = proc_reconfigure, +}; + +static int proc_init_fs_context(struct fs_context *fc) +{ + struct proc_fs_context *ctx; + + ctx = kzalloc(sizeof(struct proc_fs_context), GFP_KERNEL); + if (!ctx) + return -ENOMEM; - return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super); + ctx->pid_ns = get_pid_ns(task_active_pid_ns(current)); + fc->fs_private = ctx; + fc->ops = &proc_fs_context_ops; + return 0; } static void proc_kill_sb(struct super_block *sb) @@ -164,10 +207,11 @@ static void proc_kill_sb(struct super_block *sb) } static struct file_system_type proc_fs_type = { - .name = "proc", - .mount = proc_mount, - .kill_sb = proc_kill_sb, - .fs_flags = FS_USERNS_MOUNT, + .name = "proc", + .init_fs_context = proc_init_fs_context, + .parameters = &proc_fs_parameters, + .kill_sb = proc_kill_sb, + .fs_flags = FS_USERNS_MOUNT, }; void __init proc_root_init(void) @@ -205,7 +249,7 @@ 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); } @@ -258,9 +302,28 @@ struct proc_dir_entry proc_root = { int pid_ns_prepare_proc(struct pid_namespace *ns) { + struct proc_fs_context *ctx; + struct fs_context *fc; struct vfsmount *mnt; - mnt = kern_mount_data(&proc_fs_type, ns); + fc = fs_context_for_mount(&proc_fs_type, SB_KERNMOUNT); + if (IS_ERR(fc)) + return PTR_ERR(fc); + + if (fc->user_ns != ns->user_ns) { + put_user_ns(fc->user_ns); + fc->user_ns = get_user_ns(ns->user_ns); + } + + ctx = fc->fs_private; + if (ctx->pid_ns != ns) { + put_pid_ns(ctx->pid_ns); + get_pid_ns(ns); + ctx->pid_ns = ns; + } + + mnt = fc_mount(fc); + put_fs_context(fc); if (IS_ERR(mnt)) return PTR_ERR(mnt);

[24/43] proc: Add fs_context support to procfs

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Patch