| 1 | #include <linux/proc_fs.h> |
| 2 | #include <linux/nsproxy.h> |
| 3 | #include <linux/ptrace.h> |
| 4 | #include <linux/namei.h> |
| 5 | #include <linux/file.h> |
| 6 | #include <linux/utsname.h> |
| 7 | #include <net/net_namespace.h> |
| 8 | #include <linux/ipc_namespace.h> |
| 9 | #include <linux/pid_namespace.h> |
| 10 | #include <linux/user_namespace.h> |
| 11 | #include "internal.h" |
| 12 | |
| 13 | |
| 14 | static const struct proc_ns_operations *ns_entries[] = { |
| 15 | #ifdef CONFIG_NET_NS |
| 16 | &netns_operations, |
| 17 | #endif |
| 18 | #ifdef CONFIG_UTS_NS |
| 19 | &utsns_operations, |
| 20 | #endif |
| 21 | #ifdef CONFIG_IPC_NS |
| 22 | &ipcns_operations, |
| 23 | #endif |
| 24 | #ifdef CONFIG_PID_NS |
| 25 | &pidns_operations, |
| 26 | #endif |
| 27 | #ifdef CONFIG_USER_NS |
| 28 | &userns_operations, |
| 29 | #endif |
| 30 | &mntns_operations, |
| 31 | #ifdef CONFIG_CGROUPS |
| 32 | &cgroupns_operations, |
| 33 | #endif |
| 34 | }; |
| 35 | |
| 36 | static const char *proc_ns_get_link(struct dentry *dentry, |
| 37 | struct inode *inode, |
| 38 | struct delayed_call *done) |
| 39 | { |
| 40 | const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; |
| 41 | struct task_struct *task; |
| 42 | struct path ns_path; |
| 43 | void *error = ERR_PTR(-EACCES); |
| 44 | |
| 45 | if (!dentry) |
| 46 | return ERR_PTR(-ECHILD); |
| 47 | |
| 48 | task = get_proc_task(inode); |
| 49 | if (!task) |
| 50 | return error; |
| 51 | |
| 52 | if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { |
| 53 | error = ns_get_path(&ns_path, task, ns_ops); |
| 54 | if (!error) |
| 55 | nd_jump_link(&ns_path); |
| 56 | } |
| 57 | put_task_struct(task); |
| 58 | return error; |
| 59 | } |
| 60 | |
| 61 | static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen) |
| 62 | { |
| 63 | struct inode *inode = d_inode(dentry); |
| 64 | const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; |
| 65 | struct task_struct *task; |
| 66 | char name[50]; |
| 67 | int res = -EACCES; |
| 68 | |
| 69 | task = get_proc_task(inode); |
| 70 | if (!task) |
| 71 | return res; |
| 72 | |
| 73 | if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { |
| 74 | res = ns_get_name(name, sizeof(name), task, ns_ops); |
| 75 | if (res >= 0) |
| 76 | res = readlink_copy(buffer, buflen, name); |
| 77 | } |
| 78 | put_task_struct(task); |
| 79 | return res; |
| 80 | } |
| 81 | |
| 82 | static const struct inode_operations proc_ns_link_inode_operations = { |
| 83 | .readlink = proc_ns_readlink, |
| 84 | .get_link = proc_ns_get_link, |
| 85 | .setattr = proc_setattr, |
| 86 | }; |
| 87 | |
| 88 | static int proc_ns_instantiate(struct inode *dir, |
| 89 | struct dentry *dentry, struct task_struct *task, const void *ptr) |
| 90 | { |
| 91 | const struct proc_ns_operations *ns_ops = ptr; |
| 92 | struct inode *inode; |
| 93 | struct proc_inode *ei; |
| 94 | |
| 95 | inode = proc_pid_make_inode(dir->i_sb, task); |
| 96 | if (!inode) |
| 97 | goto out; |
| 98 | |
| 99 | ei = PROC_I(inode); |
| 100 | inode->i_mode = S_IFLNK|S_IRWXUGO; |
| 101 | inode->i_op = &proc_ns_link_inode_operations; |
| 102 | ei->ns_ops = ns_ops; |
| 103 | |
| 104 | d_set_d_op(dentry, &pid_dentry_operations); |
| 105 | d_add(dentry, inode); |
| 106 | /* Close the race of the process dying before we return the dentry */ |
| 107 | if (pid_revalidate(dentry, 0)) |
| 108 | return 0; |
| 109 | out: |
| 110 | return -ENOENT; |
| 111 | } |
| 112 | |
| 113 | static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx) |
| 114 | { |
| 115 | struct task_struct *task = get_proc_task(file_inode(file)); |
| 116 | const struct proc_ns_operations **entry, **last; |
| 117 | |
| 118 | if (!task) |
| 119 | return -ENOENT; |
| 120 | |
| 121 | if (!dir_emit_dots(file, ctx)) |
| 122 | goto out; |
| 123 | if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries)) |
| 124 | goto out; |
| 125 | entry = ns_entries + (ctx->pos - 2); |
| 126 | last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; |
| 127 | while (entry <= last) { |
| 128 | const struct proc_ns_operations *ops = *entry; |
| 129 | if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name), |
| 130 | proc_ns_instantiate, task, ops)) |
| 131 | break; |
| 132 | ctx->pos++; |
| 133 | entry++; |
| 134 | } |
| 135 | out: |
| 136 | put_task_struct(task); |
| 137 | return 0; |
| 138 | } |
| 139 | |
| 140 | const struct file_operations proc_ns_dir_operations = { |
| 141 | .read = generic_read_dir, |
| 142 | .iterate_shared = proc_ns_dir_readdir, |
| 143 | .llseek = generic_file_llseek, |
| 144 | }; |
| 145 | |
| 146 | static struct dentry *proc_ns_dir_lookup(struct inode *dir, |
| 147 | struct dentry *dentry, unsigned int flags) |
| 148 | { |
| 149 | int error; |
| 150 | struct task_struct *task = get_proc_task(dir); |
| 151 | const struct proc_ns_operations **entry, **last; |
| 152 | unsigned int len = dentry->d_name.len; |
| 153 | |
| 154 | error = -ENOENT; |
| 155 | |
| 156 | if (!task) |
| 157 | goto out_no_task; |
| 158 | |
| 159 | last = &ns_entries[ARRAY_SIZE(ns_entries)]; |
| 160 | for (entry = ns_entries; entry < last; entry++) { |
| 161 | if (strlen((*entry)->name) != len) |
| 162 | continue; |
| 163 | if (!memcmp(dentry->d_name.name, (*entry)->name, len)) |
| 164 | break; |
| 165 | } |
| 166 | if (entry == last) |
| 167 | goto out; |
| 168 | |
| 169 | error = proc_ns_instantiate(dir, dentry, task, *entry); |
| 170 | out: |
| 171 | put_task_struct(task); |
| 172 | out_no_task: |
| 173 | return ERR_PTR(error); |
| 174 | } |
| 175 | |
| 176 | const struct inode_operations proc_ns_dir_inode_operations = { |
| 177 | .lookup = proc_ns_dir_lookup, |
| 178 | .getattr = pid_getattr, |
| 179 | .setattr = proc_setattr, |
| 180 | }; |