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