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, 35 struct delayed_call *done) 36 { 37 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; 38 struct task_struct *task; 39 struct path ns_path; 40 void *error = ERR_PTR(-EACCES); 41 42 if (!dentry) 43 return ERR_PTR(-ECHILD); 44 45 task = get_proc_task(inode); 46 if (!task) 47 return error; 48 49 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { 50 error = ns_get_path(&ns_path, task, ns_ops); 51 if (!error) 52 nd_jump_link(&ns_path); 53 } 54 put_task_struct(task); 55 return error; 56 } 57 58 static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen) 59 { 60 struct inode *inode = d_inode(dentry); 61 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; 62 struct task_struct *task; 63 char name[50]; 64 int res = -EACCES; 65 66 task = get_proc_task(inode); 67 if (!task) 68 return res; 69 70 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { 71 res = ns_get_name(name, sizeof(name), task, ns_ops); 72 if (res >= 0) 73 res = readlink_copy(buffer, buflen, name); 74 } 75 put_task_struct(task); 76 return res; 77 } 78 79 static const struct inode_operations proc_ns_link_inode_operations = { 80 .readlink = proc_ns_readlink, 81 .get_link = proc_ns_get_link, 82 .setattr = proc_setattr, 83 }; 84 85 static int proc_ns_instantiate(struct inode *dir, 86 struct dentry *dentry, struct task_struct *task, const void *ptr) 87 { 88 const struct proc_ns_operations *ns_ops = ptr; 89 struct inode *inode; 90 struct proc_inode *ei; 91 92 inode = proc_pid_make_inode(dir->i_sb, task); 93 if (!inode) 94 goto out; 95 96 ei = PROC_I(inode); 97 inode->i_mode = S_IFLNK|S_IRWXUGO; 98 inode->i_op = &proc_ns_link_inode_operations; 99 ei->ns_ops = ns_ops; 100 101 d_set_d_op(dentry, &pid_dentry_operations); 102 d_add(dentry, inode); 103 /* Close the race of the process dying before we return the dentry */ 104 if (pid_revalidate(dentry, 0)) 105 return 0; 106 out: 107 return -ENOENT; 108 } 109 110 static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx) 111 { 112 struct task_struct *task = get_proc_task(file_inode(file)); 113 const struct proc_ns_operations **entry, **last; 114 115 if (!task) 116 return -ENOENT; 117 118 if (!dir_emit_dots(file, ctx)) 119 goto out; 120 if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries)) 121 goto out; 122 entry = ns_entries + (ctx->pos - 2); 123 last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; 124 while (entry <= last) { 125 const struct proc_ns_operations *ops = *entry; 126 if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name), 127 proc_ns_instantiate, task, ops)) 128 break; 129 ctx->pos++; 130 entry++; 131 } 132 out: 133 put_task_struct(task); 134 return 0; 135 } 136 137 const struct file_operations proc_ns_dir_operations = { 138 .read = generic_read_dir, 139 .iterate = proc_ns_dir_readdir, 140 }; 141 142 static struct dentry *proc_ns_dir_lookup(struct inode *dir, 143 struct dentry *dentry, unsigned int flags) 144 { 145 int error; 146 struct task_struct *task = get_proc_task(dir); 147 const struct proc_ns_operations **entry, **last; 148 unsigned int len = dentry->d_name.len; 149 150 error = -ENOENT; 151 152 if (!task) 153 goto out_no_task; 154 155 last = &ns_entries[ARRAY_SIZE(ns_entries)]; 156 for (entry = ns_entries; entry < last; entry++) { 157 if (strlen((*entry)->name) != len) 158 continue; 159 if (!memcmp(dentry->d_name.name, (*entry)->name, len)) 160 break; 161 } 162 if (entry == last) 163 goto out; 164 165 error = proc_ns_instantiate(dir, dentry, task, *entry); 166 out: 167 put_task_struct(task); 168 out_no_task: 169 return ERR_PTR(error); 170 } 171 172 const struct inode_operations proc_ns_dir_inode_operations = { 173 .lookup = proc_ns_dir_lookup, 174 .getattr = pid_getattr, 175 .setattr = proc_setattr, 176 }; 177