Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 | /* * security/tomoyo/realpath.c * * Pathname calculation functions for TOMOYO. * * Copyright (C) 2005-2010 NTT DATA CORPORATION */ #include <linux/types.h> #include <linux/mount.h> #include <linux/mnt_namespace.h> #include <linux/fs_struct.h> #include <linux/magic.h> #include <linux/slab.h> #include <net/sock.h> #include "common.h" #include "../../fs/internal.h" /** * tomoyo_encode: Convert binary string to ascii string. * * @str: String in binary format. * * Returns pointer to @str in ascii format on success, NULL otherwise. * * This function uses kzalloc(), so caller must kfree() if this function * didn't return NULL. */ char *tomoyo_encode(const char *str) { int len = 0; const char *p = str; char *cp; char *cp0; if (!p) return NULL; while (*p) { const unsigned char c = *p++; if (c == '\\') len += 2; else if (c > ' ' && c < 127) len++; else len += 4; } len++; /* Reserve space for appending "/". */ cp = kzalloc(len + 10, GFP_NOFS); if (!cp) return NULL; cp0 = cp; p = str; while (*p) { const unsigned char c = *p++; if (c == '\\') { *cp++ = '\\'; *cp++ = '\\'; } else if (c > ' ' && c < 127) { *cp++ = c; } else { *cp++ = '\\'; *cp++ = (c >> 6) + '0'; *cp++ = ((c >> 3) & 7) + '0'; *cp++ = (c & 7) + '0'; } } return cp0; } /** * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root. * * @path: Pointer to "struct path". * * Returns the realpath of the given @path on success, NULL otherwise. * * If dentry is a directory, trailing '/' is appended. * Characters out of 0x20 < c < 0x7F range are converted to * \ooo style octal string. * Character \ is converted to \\ string. * * These functions use kzalloc(), so the caller must call kfree() * if these functions didn't return NULL. */ char *tomoyo_realpath_from_path(struct path *path) { char *buf = NULL; char *name = NULL; unsigned int buf_len = PAGE_SIZE / 2; struct dentry *dentry = path->dentry; bool is_dir; if (!dentry) return NULL; is_dir = dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode); while (1) { char *pos; buf_len <<= 1; kfree(buf); buf = kmalloc(buf_len, GFP_NOFS); if (!buf) break; /* Get better name for socket. */ if (dentry->d_sb && dentry->d_sb->s_magic == SOCKFS_MAGIC) { struct inode *inode = dentry->d_inode; struct socket *sock = inode ? SOCKET_I(inode) : NULL; struct sock *sk = sock ? sock->sk : NULL; if (sk) { snprintf(buf, buf_len - 1, "socket:[family=%u:" "type=%u:protocol=%u]", sk->sk_family, sk->sk_type, sk->sk_protocol); } else { snprintf(buf, buf_len - 1, "socket:[unknown]"); } name = tomoyo_encode(buf); break; } /* For "socket:[\$]" and "pipe:[\$]". */ if (dentry->d_op && dentry->d_op->d_dname) { pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1); if (IS_ERR(pos)) continue; name = tomoyo_encode(pos); break; } /* If we don't have a vfsmount, we can't calculate. */ if (!path->mnt) break; pos = d_absolute_path(path, buf, buf_len - 1); /* If path is disconnected, use "[unknown]" instead. */ if (pos == ERR_PTR(-EINVAL)) { name = tomoyo_encode("[unknown]"); break; } /* Prepend "/proc" prefix if using internal proc vfs mount. */ if (!IS_ERR(pos) && (path->mnt->mnt_flags & MNT_INTERNAL) && (path->mnt->mnt_sb->s_magic == PROC_SUPER_MAGIC)) { pos -= 5; if (pos >= buf) memcpy(pos, "/proc", 5); else pos = ERR_PTR(-ENOMEM); } if (IS_ERR(pos)) continue; name = tomoyo_encode(pos); break; } kfree(buf); if (!name) tomoyo_warn_oom(__func__); else if (is_dir && *name) { /* Append trailing '/' if dentry is a directory. */ char *pos = name + strlen(name) - 1; if (*pos != '/') /* * This is OK because tomoyo_encode() reserves space * for appending "/". */ *++pos = '/'; } return name; } /** * tomoyo_realpath_nofollow - Get realpath of a pathname. * * @pathname: The pathname to solve. * * Returns the realpath of @pathname on success, NULL otherwise. */ char *tomoyo_realpath_nofollow(const char *pathname) { struct path path; if (pathname && kern_path(pathname, 0, &path) == 0) { char *buf = tomoyo_realpath_from_path(&path); path_put(&path); return buf; } return NULL; } |