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 *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 if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) 59 goto out; 60 61 error = ns_get_path(&ns_path, task, ns_ops); 62 if (error) 63 goto out; 64 65 error = nd_jump_link(&ns_path); 66 out: 67 put_task_struct(task); 68 return ERR_PTR(error); 69 } 70 71 static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen) 72 { 73 struct inode *inode = d_inode(dentry); 74 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; 75 struct task_struct *task; 76 char name[50]; 77 int res = -EACCES; 78 79 task = get_proc_task(inode); 80 if (!task) 81 return res; 82 83 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { 84 res = ns_get_name(name, sizeof(name), task, ns_ops); 85 if (res >= 0) 86 res = readlink_copy(buffer, buflen, name); 87 } 88 put_task_struct(task); 89 return res; 90 } 91 92 static const struct inode_operations proc_ns_link_inode_operations = { 93 .readlink = proc_ns_readlink, 94 .get_link = proc_ns_get_link, 95 .setattr = proc_setattr, 96 }; 97 98 static struct dentry *proc_ns_instantiate(struct dentry *dentry, 99 struct task_struct *task, const void *ptr) 100 { 101 const struct proc_ns_operations *ns_ops = ptr; 102 struct inode *inode; 103 struct proc_inode *ei; 104 105 inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK | S_IRWXUGO); 106 if (!inode) 107 return ERR_PTR(-ENOENT); 108 109 ei = PROC_I(inode); 110 inode->i_op = &proc_ns_link_inode_operations; 111 ei->ns_ops = ns_ops; 112 pid_update_inode(task, inode); 113 114 d_set_d_op(dentry, &pid_dentry_operations); 115 return d_splice_alias(inode, dentry); 116 } 117 118 static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx) 119 { 120 struct task_struct *task = get_proc_task(file_inode(file)); 121 const struct proc_ns_operations **entry, **last; 122 123 if (!task) 124 return -ENOENT; 125 126 if (!dir_emit_dots(file, ctx)) 127 goto out; 128 if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries)) 129 goto out; 130 entry = ns_entries + (ctx->pos - 2); 131 last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; 132 while (entry <= last) { 133 const struct proc_ns_operations *ops = *entry; 134 if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name), 135 proc_ns_instantiate, task, ops)) 136 break; 137 ctx->pos++; 138 entry++; 139 } 140 out: 141 put_task_struct(task); 142 return 0; 143 } 144 145 const struct file_operations proc_ns_dir_operations = { 146 .read = generic_read_dir, 147 .iterate_shared = proc_ns_dir_readdir, 148 .llseek = generic_file_llseek, 149 }; 150 151 static struct dentry *proc_ns_dir_lookup(struct inode *dir, 152 struct dentry *dentry, unsigned int flags) 153 { 154 struct task_struct *task = get_proc_task(dir); 155 const struct proc_ns_operations **entry, **last; 156 unsigned int len = dentry->d_name.len; 157 struct dentry *res = ERR_PTR(-ENOENT); 158 159 if (!task) 160 goto out_no_task; 161 162 last = &ns_entries[ARRAY_SIZE(ns_entries)]; 163 for (entry = ns_entries; entry < last; entry++) { 164 if (strlen((*entry)->name) != len) 165 continue; 166 if (!memcmp(dentry->d_name.name, (*entry)->name, len)) 167 break; 168 } 169 if (entry == last) 170 goto out; 171 172 res = proc_ns_instantiate(dentry, task, *entry); 173 out: 174 put_task_struct(task); 175 out_no_task: 176 return res; 177 } 178 179 const struct inode_operations proc_ns_dir_inode_operations = { 180 .lookup = proc_ns_dir_lookup, 181 .getattr = pid_getattr, 182 .setattr = proc_setattr, 183 }; 184