[RFC,1/4] proc: add proc_fs_info struct to store proc options

Message ID	1490887379-25880-2-git-send-email-tixxdz@gmail.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-security-module-owner@kernel.org> From: Djalal Harouni <tixxdz@gmail.com> To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Andy Lutomirski <luto@kernel.org>, Alexey Gladkov <gladkov.alexey@gmail.com>, Al Viro <viro@zeniv.linux.org.uk>, <ebiederm@xmission.com>, Andrew Morton <akpm@linux-foundation.org> Cc: Linux API <linux-api@vger.kernel.org>, <kirill@shutemov.name>, Oleg Nesterov <oleg@redhat.com>, Pavel Emelyanov <xemul@parallels.com>, James Bottomley <James.Bottomley@hansenpartnership.com>, Kees Cook <keescook@chromium.org>, Dongsu Park <dpark@posteo.net>, Ingo Molnar <mingo@kernel.org>, Michal Hocko <mhocko@suse.com>, Alexey Dobriyan <adobriyan@gmail.com>, kernel-hardening@lists.openwall.com, linux-security-module@vger.kernel.org, Djalal Harouni <tixxdz@gmail.com> Subject: [PATCH RFC 1/4] proc: add proc_fs_info struct to store proc options Date: Thu, 30 Mar 2017 17:22:56 +0200 Message-Id: <1490887379-25880-2-git-send-email-tixxdz@gmail.com> In-Reply-To: <1490887379-25880-1-git-send-email-tixxdz@gmail.com> References: <1490887379-25880-1-git-send-email-tixxdz@gmail.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk

diff --git a/fs/locks.c b/fs/locks.c index 2681132..dab5058 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2617,7 +2617,8 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, unsigned int fl_pid; if (fl->fl_nspid) { - struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(file_inode(f->file)->i_sb); + struct pid_namespace *proc_pidns = fs_info->pid_ns; /* Don't let fl_pid change based on who is reading the file */ fl_pid = pid_nr_ns(fl->fl_nspid, proc_pidns); @@ -2701,7 +2702,8 @@ static int locks_show(struct seq_file *f, void *v) { struct locks_iterator *iter = f->private; struct file_lock *fl, *bfl; - struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(file_inode(f->file)->i_sb); + struct pid_namespace *proc_pidns = fs_info->pid_ns; fl = hlist_entry(v, struct file_lock, fl_link); diff --git a/fs/proc/base.c b/fs/proc/base.c index c87b6b9..cd16979 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -695,7 +695,8 @@ static bool has_pid_permissions(struct pid_namespace *pid, static int proc_pid_permission(struct inode *inode, int mask) { - struct pid_namespace *pid = inode->i_sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(inode->i_sb); + struct pid_namespace *pid = fs_info->pid_ns; struct task_struct *task; bool has_perms; @@ -730,12 +731,12 @@ static const struct inode_operations proc_def_inode_operations = { static int proc_single_show(struct seq_file *m, void *v) { struct inode *inode = m->private; - struct pid_namespace *ns; struct pid *pid; struct task_struct *task; int ret; - ns = inode->i_sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(inode->i_sb); + struct pid_namespace *ns = fs_info->pid_ns; pid = proc_pid(inode); task = get_pid_task(pid, PIDTYPE_PID); if (!task) @@ -1732,9 +1733,10 @@ struct inode *proc_pid_make_inode(struct super_block * sb, int pid_getattr(const struct path *path, struct kstat *stat, u32 request_mask, unsigned int query_flags) { - struct inode *inode = d_inode(path->dentry); struct task_struct *task; - struct pid_namespace *pid = path->dentry->d_sb->s_fs_info; + struct inode *inode = d_inode(path->dentry); + struct proc_fs_info *fs_info = proc_sb(inode->i_sb); + struct pid_namespace *pid = fs_info->pid_ns; generic_fillattr(inode, stat); @@ -2249,6 +2251,8 @@ static const struct seq_operations proc_timers_seq_ops = { static int proc_timers_open(struct inode *inode, struct file *file) { struct timers_private *tp; + struct proc_fs_info *fs_info = proc_sb(inode->i_sb); + struct pid_namespace *ns = fs_info->pid_ns; tp = __seq_open_private(file, &proc_timers_seq_ops, sizeof(struct timers_private)); @@ -2256,7 +2260,7 @@ static int proc_timers_open(struct inode *inode, struct file *file) return -ENOMEM; tp->pid = proc_pid(inode); - tp->ns = inode->i_sb->s_fs_info; + tp->ns = ns; return 0; } @@ -3077,13 +3081,13 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsign int result = -ENOENT; struct task_struct *task; unsigned tgid; - struct pid_namespace *ns; + struct proc_fs_info *fs_info = proc_sb(dir->i_sb); + struct pid_namespace *ns = fs_info->pid_ns; tgid = name_to_int(&dentry->d_name); if (tgid == ~0U) goto out; - ns = dentry->d_sb->s_fs_info; rcu_read_lock(); task = find_task_by_pid_ns(tgid, ns); if (task) @@ -3147,7 +3151,8 @@ static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter ite int proc_pid_readdir(struct file *file, struct dir_context *ctx) { struct tgid_iter iter; - struct pid_namespace *ns = file_inode(file)->i_sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(file_inode(file)->i_sb); + struct pid_namespace *ns = fs_info->pid_ns; loff_t pos = ctx->pos; if (pos >= PID_MAX_LIMIT + TGID_OFFSET) @@ -3371,7 +3376,8 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry struct task_struct *task; struct task_struct *leader = get_proc_task(dir); unsigned tid; - struct pid_namespace *ns; + struct proc_fs_info *fs_info = proc_sb(dentry->d_sb); + struct pid_namespace *ns = fs_info->pid_ns; if (!leader) goto out_no_task; @@ -3380,7 +3386,6 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry if (tid == ~0U) goto out; - ns = dentry->d_sb->s_fs_info; rcu_read_lock(); task = find_task_by_pid_ns(tid, ns); if (task) @@ -3482,7 +3487,8 @@ static int proc_task_readdir(struct file *file, struct dir_context *ctx) { struct inode *inode = file_inode(file); struct task_struct *task; - struct pid_namespace *ns; + struct proc_fs_info *fs_info = proc_sb(inode->i_sb); + struct pid_namespace *ns = fs_info->pid_ns; int tid; if (proc_inode_is_dead(inode)) @@ -3494,7 +3500,6 @@ static int proc_task_readdir(struct file *file, struct dir_context *ctx) /* f_version caches the tgid value that the last readdir call couldn't * return. lseek aka telldir automagically resets f_version to 0. */ - ns = inode->i_sb->s_fs_info; tid = (int)file->f_version; file->f_version = 0; for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns); diff --git a/fs/proc/generic.c b/fs/proc/generic.c index ee27feb..49c8cb9 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -28,6 +28,11 @@ static DEFINE_RWLOCK(proc_subdir_lock); +struct proc_fs_info *proc_sb(struct super_block *sb) +{ + return sb->s_fs_info; +} + static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de) { if (len < de->namelen) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 2cc7a80..e708288 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -103,7 +103,8 @@ void __init proc_init_inodecache(void) static int proc_show_options(struct seq_file *seq, struct dentry *root) { struct super_block *sb = root->d_sb; - struct pid_namespace *pid = sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(sb); + struct pid_namespace *pid = fs_info->pid_ns; if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID)) seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid)); @@ -473,7 +474,8 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) int proc_fill_super(struct super_block *s, void *data, int silent) { - struct pid_namespace *ns = get_pid_ns(s->s_fs_info); + struct proc_fs_info *fs_info = proc_sb(s); + struct pid_namespace *ns = get_pid_ns(fs_info->pid_ns); struct inode *root_inode; int ret; @@ -495,7 +497,7 @@ 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) { diff --git a/fs/proc/root.c b/fs/proc/root.c index deecb39..a683e93 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -15,6 +15,7 @@ #include <linux/init.h> #include <linux/sched.h> #include <linux/sched/stat.h> +#include <linux/slab.h> #include <linux/module.h> #include <linux/bitops.h> #include <linux/user_namespace.h> @@ -79,16 +80,46 @@ int proc_parse_options(char *options, struct pid_namespace *pid) int proc_remount(struct super_block *sb, int *flags, char *data) { - struct pid_namespace *pid = sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(sb); + struct pid_namespace *pid = fs_info->pid_ns; sync_filesystem(sb); return !proc_parse_options(data, pid); } +static int proc_test_super(struct super_block *s, void *data) +{ + int ret = 0; + struct proc_fs_info *p = data; + struct proc_fs_info *fs_info = proc_sb(s); + + if (p->version == PROC_FS_V1 && fs_info->version == PROC_FS_V1 && + p->pid_ns == fs_info->pid_ns) + ret = 1; + + return ret; +} + +static int proc_set_super(struct super_block *sb, void *data) +{ + sb->s_fs_info = data; + return set_anon_super(sb, NULL); +} + static struct dentry *proc_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { + int error; + struct super_block *sb; struct pid_namespace *ns; + struct proc_fs_info *fs_info; + + if (!(flags & MS_KERNMOUNT) && !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + + fs_info = kzalloc(sizeof(*fs_info), GFP_NOFS); + if (!fs_info) + return ERR_PTR(-ENOMEM); if (flags & MS_KERNMOUNT) { ns = data; @@ -97,20 +128,60 @@ static struct dentry *proc_mount(struct file_system_type *fs_type, ns = task_active_pid_ns(current); } - return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super); + fs_info->pid_ns = ns; + fs_info->version = PROC_FS_V1; + refcount_set(&fs_info->users, 1); + + sb = sget_userns(fs_type, proc_test_super, proc_set_super, flags, + ns->user_ns, fs_info); + if (IS_ERR(sb)) { + error = PTR_ERR(sb); + goto error_fs_info; + } + + if (sb->s_root) { + struct proc_fs_info *old = proc_sb(sb); + + refcount_inc(&old->users); + kfree(fs_info); + } else { + error = proc_fill_super(sb, data, flags & MS_SILENT ? 1 : 0); + if (error) { + deactivate_locked_super(sb); + goto error; + } + + sb->s_flags |= MS_ACTIVE; + } + + return dget(sb->s_root); + +error_fs_info: + kfree(fs_info); +error: + return ERR_PTR(error); } -static void proc_kill_sb(struct super_block *sb) +static void proc_destroy_sb(struct super_block *sb) { - struct pid_namespace *ns; + struct proc_fs_info *fs_info = proc_sb(sb); + struct pid_namespace *ns = (struct pid_namespace *)fs_info->pid_ns; - ns = (struct pid_namespace *)sb->s_fs_info; if (ns->proc_self) dput(ns->proc_self); if (ns->proc_thread_self) dput(ns->proc_thread_self); kill_anon_super(sb); put_pid_ns(ns); + kfree(fs_info); +} + +static void proc_kill_sb(struct super_block *sb) +{ + struct proc_fs_info *fs_info = proc_sb(sb); + + if (refcount_dec_and_test(&fs_info->users)) + proc_destroy_sb(sb); } static struct file_system_type proc_fs_type = { diff --git a/fs/proc/self.c b/fs/proc/self.c index 39857f6..9f95174 100644 --- a/fs/proc/self.c +++ b/fs/proc/self.c @@ -10,7 +10,8 @@ static const char *proc_self_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { - struct pid_namespace *ns = inode->i_sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(inode->i_sb); + struct pid_namespace *ns = fs_info->pid_ns; pid_t tgid = task_tgid_nr_ns(current, ns); char *name; @@ -34,9 +35,10 @@ static unsigned self_inum; int proc_setup_self(struct super_block *s) { struct inode *root_inode = d_inode(s->s_root); - struct pid_namespace *ns = s->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(s); + struct pid_namespace *ns = fs_info->pid_ns; struct dentry *self; - + inode_lock(root_inode); self = d_alloc_name(s->s_root, "self"); if (self) { diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c index 20614b6..13d9aef 100644 --- a/fs/proc/thread_self.c +++ b/fs/proc/thread_self.c @@ -10,7 +10,8 @@ static const char *proc_thread_self_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { - struct pid_namespace *ns = inode->i_sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb(inode->i_sb); + struct pid_namespace *ns = fs_info->pid_ns; pid_t tgid = task_tgid_nr_ns(current, ns); pid_t pid = task_pid_nr_ns(current, ns); char *name; @@ -34,8 +35,9 @@ static unsigned thread_self_inum; int proc_setup_thread_self(struct super_block *s) { + struct proc_fs_info *fs_info = proc_sb(s); + struct pid_namespace *ns = fs_info->pid_ns; struct inode *root_inode = d_inode(s->s_root); - struct pid_namespace *ns = s->s_fs_info; struct dentry *thread_self; inode_lock(root_inode); diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c index b5713fe..d0ae937 100644 --- a/fs/proc_namespace.c +++ b/fs/proc_namespace.c @@ -36,23 +36,23 @@ static unsigned mounts_poll(struct file *file, poll_table *wait) return res; } -struct proc_fs_info { +struct proc_fs_opts { int flag; const char *str; }; static int show_sb_opts(struct seq_file *m, struct super_block *sb) { - static const struct proc_fs_info fs_info[] = { + static const struct proc_fs_opts fs_opts[] = { { MS_SYNCHRONOUS, ",sync" }, { MS_DIRSYNC, ",dirsync" }, { MS_MANDLOCK, ",mand" }, { MS_LAZYTIME, ",lazytime" }, { 0, NULL } }; - const struct proc_fs_info *fs_infop; + const struct proc_fs_opts *fs_infop; - for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { + for (fs_infop = fs_opts; fs_infop->flag; fs_infop++) { if (sb->s_flags & fs_infop->flag) seq_puts(m, fs_infop->str); } @@ -62,7 +62,7 @@ static int show_sb_opts(struct seq_file *m, struct super_block *sb) static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) { - static const struct proc_fs_info mnt_info[] = { + static const struct proc_fs_opts mnt_opts[] = { { MNT_NOSUID, ",nosuid" }, { MNT_NODEV, ",nodev" }, { MNT_NOEXEC, ",noexec" }, @@ -71,9 +71,9 @@ static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) { MNT_RELATIME, ",relatime" }, { 0, NULL } }; - const struct proc_fs_info *fs_infop; + const struct proc_fs_opts *fs_infop; - for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) { + for (fs_infop = mnt_opts; fs_infop->flag; fs_infop++) { if (mnt->mnt_flags & fs_infop->flag) seq_puts(m, fs_infop->str); } diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 2d2bf59..e1cb9c3 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -6,11 +6,27 @@ #include <linux/types.h> #include <linux/fs.h> +#include <linux/refcount.h> + +enum { + PROC_FS_V1 = 1, + PROC_FS_V2 = 2, +}; + +struct proc_fs_info { + refcount_t users; + struct pid_namespace *pid_ns; + kgid_t pid_gid; + int hide_pid; + int version; +}; struct proc_dir_entry; #ifdef CONFIG_PROC_FS +extern struct proc_fs_info *proc_sb(struct super_block *sb); + extern void proc_root_init(void); extern void proc_flush_task(struct task_struct *); @@ -53,6 +69,7 @@ static inline void proc_flush_task(struct task_struct *task) { } +extern inline struct proc_fs_info *proc_sb(struct super_block *sb) { return NULL;} static inline struct proc_dir_entry *proc_symlink(const char *name, struct proc_dir_entry *parent,const char *dest) { return NULL;} static inline struct proc_dir_entry *proc_mkdir(const char *name,

[RFC,1/4] proc: add proc_fs_info struct to store proc options

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