1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/proc_fs.h> 3 #include <linux/nsproxy.h> 4 #include <linux/ptrace.h> 5 #include <linux/namei.h> 6 #include <linux/file.h> 7 #include <linux/utsname.h> 8 #include <net/net_namespace.h> 9 #include <linux/ipc_namespace.h> 10 #include <linux/pid_namespace.h> 11 #include <linux/user_namespace.h> 12 #include "internal.h" 13 14 15 static const struct proc_ns_operations *const ns_entries[] = { 16 #ifdef CONFIG_NET_NS 17 &netns_operations, 18 #endif 19 #ifdef CONFIG_UTS_NS 20 &utsns_operations, 21 #endif 22 #ifdef CONFIG_IPC_NS 23 &ipcns_operations, 24 #endif 25 #ifdef CONFIG_PID_NS 26 &pidns_operations, 27 &pidns_for_children_operations, 28 #endif 29 #ifdef CONFIG_USER_NS 30 &userns_operations, 31 #endif 32 &mntns_operations, 33 #ifdef CONFIG_CGROUPS 34 &cgroupns_operations, 35 #endif 36 #ifdef CONFIG_TIME_NS 37 &timens_operations, 38 &timens_for_children_operations, 39 #endif 40 }; 41 42 static const char *proc_ns_get_link(struct dentry *dentry, 43 struct inode *inode, 44 struct delayed_call *done) 45 { 46 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; 47 struct task_struct *task; 48 struct path ns_path; 49 int error = -EACCES; 50 51 if (!dentry) 52 return ERR_PTR(-ECHILD); 53 54 task = get_proc_task(inode); 55 if (!task) 56 return ERR_PTR(-EACCES); 57 58 error = down_read_killable(&task->signal->exec_update_lock); 59 if (error) 60 goto out_put_task; 61 62 if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) 63 goto out; 64 65 error = ns_get_path(&ns_path, task, ns_ops); 66 if (error) 67 goto out; 68 69 error = nd_jump_link(&ns_path); 70 out: 71 up_read(&task->signal->exec_update_lock); 72 out_put_task: 73 put_task_struct(task); 74 return ERR_PTR(error); 75 } 76 77 static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen) 78 { 79 struct inode *inode = d_inode(dentry); 80 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; 81 struct task_struct *task; 82 char name[50]; 83 int res = -EACCES; 84 85 task = get_proc_task(inode); 86 if (!task) 87 return res; 88 89 res = down_read_killable(&task->signal->exec_update_lock); 90 if (res) 91 goto out_put_task; 92 93 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { 94 res = ns_get_name(name, sizeof(name), task, ns_ops); 95 if (res >= 0) 96 res = readlink_copy(buffer, buflen, name, strlen(name)); 97 } 98 up_read(&task->signal->exec_update_lock); 99 out_put_task: 100 put_task_struct(task); 101 return res; 102 } 103 104 static const struct inode_operations proc_ns_link_inode_operations = { 105 .readlink = proc_ns_readlink, 106 .get_link = proc_ns_get_link, 107 .setattr = proc_nochmod_setattr, 108 }; 109 110 static struct dentry *proc_ns_instantiate(struct dentry *dentry, 111 struct task_struct *task, const void *ptr) 112 { 113 const struct proc_ns_operations *ns_ops = ptr; 114 struct inode *inode; 115 struct proc_inode *ei; 116 117 inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK | S_IRWXUGO); 118 if (!inode) 119 return ERR_PTR(-ENOENT); 120 121 ei = PROC_I(inode); 122 inode->i_op = &proc_ns_link_inode_operations; 123 ei->ns_ops = ns_ops; 124 pid_update_inode(task, inode); 125 126 return d_splice_alias_ops(inode, dentry, &pid_dentry_operations); 127 } 128 129 static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx) 130 { 131 struct task_struct *task = get_proc_task(file_inode(file)); 132 const struct proc_ns_operations *const *entry, *const *last; 133 134 if (!task) 135 return -ENOENT; 136 137 if (!dir_emit_dots(file, ctx)) 138 goto out; 139 if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries)) 140 goto out; 141 entry = ns_entries + (ctx->pos - 2); 142 last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; 143 while (entry <= last) { 144 const struct proc_ns_operations *ops = *entry; 145 if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name), 146 proc_ns_instantiate, task, ops)) 147 break; 148 ctx->pos++; 149 entry++; 150 } 151 out: 152 put_task_struct(task); 153 return 0; 154 } 155 156 const struct file_operations proc_ns_dir_operations = { 157 .read = generic_read_dir, 158 .iterate_shared = proc_ns_dir_readdir, 159 .llseek = generic_file_llseek, 160 }; 161 162 static struct dentry *proc_ns_dir_lookup(struct inode *dir, 163 struct dentry *dentry, unsigned int flags) 164 { 165 struct task_struct *task = get_proc_task(dir); 166 const struct proc_ns_operations *const *entry, *const *last; 167 unsigned int len = dentry->d_name.len; 168 struct dentry *res = ERR_PTR(-ENOENT); 169 170 if (!task) 171 goto out_no_task; 172 173 last = &ns_entries[ARRAY_SIZE(ns_entries)]; 174 for (entry = ns_entries; entry < last; entry++) { 175 if (strlen((*entry)->name) != len) 176 continue; 177 if (!memcmp(dentry->d_name.name, (*entry)->name, len)) 178 break; 179 } 180 if (entry == last) 181 goto out; 182 183 res = proc_ns_instantiate(dentry, task, *entry); 184 out: 185 put_task_struct(task); 186 out_no_task: 187 return res; 188 } 189 190 const struct inode_operations proc_ns_dir_inode_operations = { 191 .lookup = proc_ns_dir_lookup, 192 .getattr = pid_getattr, 193 .setattr = proc_nochmod_setattr, 194 }; 195