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 &pidns_for_children_operations, 27 #endif 28 #ifdef CONFIG_USER_NS 29 &userns_operations, 30 #endif 31 &mntns_operations, 32 #ifdef CONFIG_CGROUPS 33 &cgroupns_operations, 34 #endif 35 }; 36 37 static const char *proc_ns_get_link(struct dentry *dentry, 38 struct inode *inode, 39 struct delayed_call *done) 40 { 41 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; 42 struct task_struct *task; 43 struct path ns_path; 44 void *error = ERR_PTR(-EACCES); 45 46 if (!dentry) 47 return ERR_PTR(-ECHILD); 48 49 task = get_proc_task(inode); 50 if (!task) 51 return error; 52 53 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { 54 error = ns_get_path(&ns_path, task, ns_ops); 55 if (!error) 56 nd_jump_link(&ns_path); 57 } 58 put_task_struct(task); 59 return error; 60 } 61 62 static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen) 63 { 64 struct inode *inode = d_inode(dentry); 65 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; 66 struct task_struct *task; 67 char name[50]; 68 int res = -EACCES; 69 70 task = get_proc_task(inode); 71 if (!task) 72 return res; 73 74 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { 75 res = ns_get_name(name, sizeof(name), task, ns_ops); 76 if (res >= 0) 77 res = readlink_copy(buffer, buflen, name); 78 } 79 put_task_struct(task); 80 return res; 81 } 82 83 static const struct inode_operations proc_ns_link_inode_operations = { 84 .readlink = proc_ns_readlink, 85 .get_link = proc_ns_get_link, 86 .setattr = proc_setattr, 87 }; 88 89 static int proc_ns_instantiate(struct inode *dir, 90 struct dentry *dentry, struct task_struct *task, const void *ptr) 91 { 92 const struct proc_ns_operations *ns_ops = ptr; 93 struct inode *inode; 94 struct proc_inode *ei; 95 96 inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | S_IRWXUGO); 97 if (!inode) 98 goto out; 99 100 ei = PROC_I(inode); 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_shared = proc_ns_dir_readdir, 143 .llseek = generic_file_llseek, 144 }; 145 146 static struct dentry *proc_ns_dir_lookup(struct inode *dir, 147 struct dentry *dentry, unsigned int flags) 148 { 149 int error; 150 struct task_struct *task = get_proc_task(dir); 151 const struct proc_ns_operations **entry, **last; 152 unsigned int len = dentry->d_name.len; 153 154 error = -ENOENT; 155 156 if (!task) 157 goto out_no_task; 158 159 last = &ns_entries[ARRAY_SIZE(ns_entries)]; 160 for (entry = ns_entries; entry < last; entry++) { 161 if (strlen((*entry)->name) != len) 162 continue; 163 if (!memcmp(dentry->d_name.name, (*entry)->name, len)) 164 break; 165 } 166 if (entry == last) 167 goto out; 168 169 error = proc_ns_instantiate(dir, dentry, task, *entry); 170 out: 171 put_task_struct(task); 172 out_no_task: 173 return ERR_PTR(error); 174 } 175 176 const struct inode_operations proc_ns_dir_inode_operations = { 177 .lookup = proc_ns_dir_lookup, 178 .getattr = pid_getattr, 179 .setattr = proc_setattr, 180 }; 181