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-rw-r--r--fs/proc/root.c372
1 files changed, 372 insertions, 0 deletions
diff --git a/fs/proc/root.c b/fs/proc/root.c
new file mode 100644
index 000000000..5e444d4f9
--- /dev/null
+++ b/fs/proc/root.c
@@ -0,0 +1,372 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/proc/root.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * proc root directory handling functions
+ */
+
+#include <linux/uaccess.h>
+
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/sched/stat.h>
+#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/fs_parser.h>
+#include <linux/cred.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+
+#include "internal.h"
+
+struct proc_fs_context {
+ struct pid_namespace *pid_ns;
+ unsigned int mask;
+ enum proc_hidepid hidepid;
+ int gid;
+ enum proc_pidonly pidonly;
+};
+
+enum proc_param {
+ Opt_gid,
+ Opt_hidepid,
+ Opt_subset,
+};
+
+static const struct fs_parameter_spec proc_fs_parameters[] = {
+ fsparam_u32("gid", Opt_gid),
+ fsparam_string("hidepid", Opt_hidepid),
+ fsparam_string("subset", Opt_subset),
+ {}
+};
+
+static inline int valid_hidepid(unsigned int value)
+{
+ return (value == HIDEPID_OFF ||
+ value == HIDEPID_NO_ACCESS ||
+ value == HIDEPID_INVISIBLE ||
+ value == HIDEPID_NOT_PTRACEABLE);
+}
+
+static int proc_parse_hidepid_param(struct fs_context *fc, struct fs_parameter *param)
+{
+ struct proc_fs_context *ctx = fc->fs_private;
+ struct fs_parameter_spec hidepid_u32_spec = fsparam_u32("hidepid", Opt_hidepid);
+ struct fs_parse_result result;
+ int base = (unsigned long)hidepid_u32_spec.data;
+
+ if (param->type != fs_value_is_string)
+ return invalf(fc, "proc: unexpected type of hidepid value\n");
+
+ if (!kstrtouint(param->string, base, &result.uint_32)) {
+ if (!valid_hidepid(result.uint_32))
+ return invalf(fc, "proc: unknown value of hidepid - %s\n", param->string);
+ ctx->hidepid = result.uint_32;
+ return 0;
+ }
+
+ if (!strcmp(param->string, "off"))
+ ctx->hidepid = HIDEPID_OFF;
+ else if (!strcmp(param->string, "noaccess"))
+ ctx->hidepid = HIDEPID_NO_ACCESS;
+ else if (!strcmp(param->string, "invisible"))
+ ctx->hidepid = HIDEPID_INVISIBLE;
+ else if (!strcmp(param->string, "ptraceable"))
+ ctx->hidepid = HIDEPID_NOT_PTRACEABLE;
+ else
+ return invalf(fc, "proc: unknown value of hidepid - %s\n", param->string);
+
+ return 0;
+}
+
+static int proc_parse_subset_param(struct fs_context *fc, char *value)
+{
+ struct proc_fs_context *ctx = fc->fs_private;
+
+ while (value) {
+ char *ptr = strchr(value, ',');
+
+ if (ptr != NULL)
+ *ptr++ = '\0';
+
+ if (*value != '\0') {
+ if (!strcmp(value, "pid")) {
+ ctx->pidonly = PROC_PIDONLY_ON;
+ } else {
+ return invalf(fc, "proc: unsupported subset option - %s\n", value);
+ }
+ }
+ value = ptr;
+ }
+
+ return 0;
+}
+
+static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+ 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:
+ if (proc_parse_hidepid_param(fc, param))
+ return -EINVAL;
+ break;
+
+ case Opt_subset:
+ if (proc_parse_subset_param(fc, param->string) < 0)
+ return -EINVAL;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ ctx->mask |= 1 << opt;
+ return 0;
+}
+
+static void proc_apply_options(struct proc_fs_info *fs_info,
+ struct fs_context *fc,
+ struct user_namespace *user_ns)
+{
+ struct proc_fs_context *ctx = fc->fs_private;
+
+ if (ctx->mask & (1 << Opt_gid))
+ fs_info->pid_gid = make_kgid(user_ns, ctx->gid);
+ if (ctx->mask & (1 << Opt_hidepid))
+ fs_info->hide_pid = ctx->hidepid;
+ if (ctx->mask & (1 << Opt_subset))
+ fs_info->pidonly = ctx->pidonly;
+}
+
+static int proc_fill_super(struct super_block *s, struct fs_context *fc)
+{
+ struct proc_fs_context *ctx = fc->fs_private;
+ struct inode *root_inode;
+ struct proc_fs_info *fs_info;
+ int ret;
+
+ fs_info = kzalloc(sizeof(*fs_info), GFP_KERNEL);
+ if (!fs_info)
+ return -ENOMEM;
+
+ fs_info->pid_ns = get_pid_ns(ctx->pid_ns);
+ proc_apply_options(fs_info, fc, 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;
+ s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
+ s->s_blocksize = 1024;
+ s->s_blocksize_bits = 10;
+ s->s_magic = PROC_SUPER_MAGIC;
+ s->s_op = &proc_sops;
+ s->s_time_gran = 1;
+ s->s_fs_info = fs_info;
+
+ /*
+ * procfs isn't actually a stacking filesystem; however, there is
+ * too much magic going on inside it to permit stacking things on
+ * top of it
+ */
+ s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
+
+ /* procfs dentries and inodes don't require IO to create */
+ s->s_shrink.seeks = 0;
+
+ pde_get(&proc_root);
+ root_inode = proc_get_inode(s, &proc_root);
+ if (!root_inode) {
+ pr_err("proc_fill_super: get root inode failed\n");
+ return -ENOMEM;
+ }
+
+ s->s_root = d_make_root(root_inode);
+ if (!s->s_root) {
+ pr_err("proc_fill_super: allocate dentry failed\n");
+ return -ENOMEM;
+ }
+
+ ret = proc_setup_self(s);
+ if (ret) {
+ return ret;
+ }
+ return proc_setup_thread_self(s);
+}
+
+static int proc_reconfigure(struct fs_context *fc)
+{
+ struct super_block *sb = fc->root->d_sb;
+ struct proc_fs_info *fs_info = proc_sb_info(sb);
+
+ sync_filesystem(sb);
+
+ proc_apply_options(fs_info, fc, current_user_ns());
+ return 0;
+}
+
+static int proc_get_tree(struct fs_context *fc)
+{
+ return get_tree_nodev(fc, proc_fill_super);
+}
+
+static void proc_fs_context_free(struct fs_context *fc)
+{
+ struct proc_fs_context *ctx = fc->fs_private;
+
+ 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;
+
+ ctx->pid_ns = get_pid_ns(task_active_pid_ns(current));
+ put_user_ns(fc->user_ns);
+ fc->user_ns = get_user_ns(ctx->pid_ns->user_ns);
+ fc->fs_private = ctx;
+ fc->ops = &proc_fs_context_ops;
+ return 0;
+}
+
+static void proc_kill_sb(struct super_block *sb)
+{
+ struct proc_fs_info *fs_info = proc_sb_info(sb);
+
+ if (!fs_info) {
+ kill_anon_super(sb);
+ return;
+ }
+
+ dput(fs_info->proc_self);
+ dput(fs_info->proc_thread_self);
+
+ kill_anon_super(sb);
+ put_pid_ns(fs_info->pid_ns);
+ kfree(fs_info);
+}
+
+static struct file_system_type proc_fs_type = {
+ .name = "proc",
+ .init_fs_context = proc_init_fs_context,
+ .parameters = proc_fs_parameters,
+ .kill_sb = proc_kill_sb,
+ .fs_flags = FS_USERNS_MOUNT | FS_DISALLOW_NOTIFY_PERM,
+};
+
+void __init proc_root_init(void)
+{
+ proc_init_kmemcache();
+ set_proc_pid_nlink();
+ proc_self_init();
+ proc_thread_self_init();
+ proc_symlink("mounts", NULL, "self/mounts");
+
+ proc_net_init();
+ proc_mkdir("fs", NULL);
+ proc_mkdir("driver", NULL);
+ proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
+#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
+ /* just give it a mountpoint */
+ proc_create_mount_point("openprom");
+#endif
+ proc_tty_init();
+ proc_mkdir("bus", NULL);
+ proc_sys_init();
+
+ register_filesystem(&proc_fs_type);
+}
+
+static int proc_root_getattr(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int query_flags)
+{
+ generic_fillattr(d_inode(path->dentry), stat);
+ stat->nlink = proc_root.nlink + nr_processes();
+ return 0;
+}
+
+static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
+{
+ if (!proc_pid_lookup(dentry, flags))
+ return NULL;
+
+ return proc_lookup(dir, dentry, flags);
+}
+
+static int proc_root_readdir(struct file *file, struct dir_context *ctx)
+{
+ if (ctx->pos < FIRST_PROCESS_ENTRY) {
+ int error = proc_readdir(file, ctx);
+ if (unlikely(error <= 0))
+ return error;
+ ctx->pos = FIRST_PROCESS_ENTRY;
+ }
+
+ return proc_pid_readdir(file, ctx);
+}
+
+/*
+ * The root /proc directory is special, as it has the
+ * <pid> directories. Thus we don't use the generic
+ * directory handling functions for that..
+ */
+static const struct file_operations proc_root_operations = {
+ .read = generic_read_dir,
+ .iterate_shared = proc_root_readdir,
+ .llseek = generic_file_llseek,
+};
+
+/*
+ * proc root can do almost nothing..
+ */
+static const struct inode_operations proc_root_inode_operations = {
+ .lookup = proc_root_lookup,
+ .getattr = proc_root_getattr,
+};
+
+/*
+ * 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,
+ .refcnt = REFCOUNT_INIT(1),
+ .proc_iops = &proc_root_inode_operations,
+ .proc_dir_ops = &proc_root_operations,
+ .parent = &proc_root,
+ .subdir = RB_ROOT,
+ .name = "/proc",
+};