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 }; 32 33 static const char *proc_ns_get_link(struct dentry *dentry, 34 struct inode *inode, void **cookie) 35 { 36 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; 37 struct task_struct *task; 38 struct path ns_path; 39 void *error = ERR_PTR(-EACCES); 40 41 if (!dentry) 42 return ERR_PTR(-ECHILD); 43 44 task = get_proc_task(inode); 45 if (!task) 46 return error; 47 48 if (ptrace_may_access(task, PTRACE_MODE_READ)) { 49 error = ns_get_path(&ns_path, task, ns_ops); 50 if (!error) 51 nd_jump_link(&ns_path); 52 } 53 put_task_struct(task); 54 return error; 55 } 56 57 static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen) 58 { 59 struct inode *inode = d_inode(dentry); 60 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; 61 struct task_struct *task; 62 char name[50]; 63 int res = -EACCES; 64 65 task = get_proc_task(inode); 66 if (!task) 67 return res; 68 69 if (ptrace_may_access(task, PTRACE_MODE_READ)) { 70 res = ns_get_name(name, sizeof(name), task, ns_ops); 71 if (res >= 0) 72 res = readlink_copy(buffer, buflen, name); 73 } 74 put_task_struct(task); 75 return res; 76 } 77 78 static const struct inode_operations proc_ns_link_inode_operations = { 79 .readlink = proc_ns_readlink, 80 .get_link = proc_ns_get_link, 81 .setattr = proc_setattr, 82 }; 83 84 static int proc_ns_instantiate(struct inode *dir, 85 struct dentry *dentry, struct task_struct *task, const void *ptr) 86 { 87 const struct proc_ns_operations *ns_ops = ptr; 88 struct inode *inode; 89 struct proc_inode *ei; 90 91 inode = proc_pid_make_inode(dir->i_sb, task); 92 if (!inode) 93 goto out; 94 95 ei = PROC_I(inode); 96 inode->i_mode = S_IFLNK|S_IRWXUGO; 97 inode->i_op = &proc_ns_link_inode_operations; 98 ei->ns_ops = ns_ops; 99 100 d_set_d_op(dentry, &pid_dentry_operations); 101 d_add(dentry, inode); 102 /* Close the race of the process dying before we return the dentry */ 103 if (pid_revalidate(dentry, 0)) 104 return 0; 105 out: 106 return -ENOENT; 107 } 108 109 static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx) 110 { 111 struct task_struct *task = get_proc_task(file_inode(file)); 112 const struct proc_ns_operations **entry, **last; 113 114 if (!task) 115 return -ENOENT; 116 117 if (!dir_emit_dots(file, ctx)) 118 goto out; 119 if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries)) 120 goto out; 121 entry = ns_entries + (ctx->pos - 2); 122 last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; 123 while (entry <= last) { 124 const struct proc_ns_operations *ops = *entry; 125 if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name), 126 proc_ns_instantiate, task, ops)) 127 break; 128 ctx->pos++; 129 entry++; 130 } 131 out: 132 put_task_struct(task); 133 return 0; 134 } 135 136 const struct file_operations proc_ns_dir_operations = { 137 .read = generic_read_dir, 138 .iterate = proc_ns_dir_readdir, 139 }; 140 141 static struct dentry *proc_ns_dir_lookup(struct inode *dir, 142 struct dentry *dentry, unsigned int flags) 143 { 144 int error; 145 struct task_struct *task = get_proc_task(dir); 146 const struct proc_ns_operations **entry, **last; 147 unsigned int len = dentry->d_name.len; 148 149 error = -ENOENT; 150 151 if (!task) 152 goto out_no_task; 153 154 last = &ns_entries[ARRAY_SIZE(ns_entries)]; 155 for (entry = ns_entries; entry < last; entry++) { 156 if (strlen((*entry)->name) != len) 157 continue; 158 if (!memcmp(dentry->d_name.name, (*entry)->name, len)) 159 break; 160 } 161 if (entry == last) 162 goto out; 163 164 error = proc_ns_instantiate(dir, dentry, task, *entry); 165 out: 166 put_task_struct(task); 167 out_no_task: 168 return ERR_PTR(error); 169 } 170 171 const struct inode_operations proc_ns_dir_inode_operations = { 172 .lookup = proc_ns_dir_lookup, 173 .getattr = pid_getattr, 174 .setattr = proc_setattr, 175 }; 176