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 = proc_ns_dir_readdir, 143 }; 144 145 static struct dentry *proc_ns_dir_lookup(struct inode *dir, 146 struct dentry *dentry, unsigned int flags) 147 { 148 int error; 149 struct task_struct *task = get_proc_task(dir); 150 const struct proc_ns_operations **entry, **last; 151 unsigned int len = dentry->d_name.len; 152 153 error = -ENOENT; 154 155 if (!task) 156 goto out_no_task; 157 158 last = &ns_entries[ARRAY_SIZE(ns_entries)]; 159 for (entry = ns_entries; entry < last; entry++) { 160 if (strlen((*entry)->name) != len) 161 continue; 162 if (!memcmp(dentry->d_name.name, (*entry)->name, len)) 163 break; 164 } 165 if (entry == last) 166 goto out; 167 168 error = proc_ns_instantiate(dir, dentry, task, *entry); 169 out: 170 put_task_struct(task); 171 out_no_task: 172 return ERR_PTR(error); 173 } 174 175 const struct inode_operations proc_ns_dir_inode_operations = { 176 .lookup = proc_ns_dir_lookup, 177 .getattr = pid_getattr, 178 .setattr = proc_setattr, 179 }; 180