1/* 2 * linux/net/sunrpc/gss_generic_token.c 3 * 4 * Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/generic/util_token.c 5 * 6 * Copyright (c) 2000 The Regents of the University of Michigan. 7 * All rights reserved. 8 * 9 * Andy Adamson <andros@umich.edu> 10 */ 11 12/* 13 * Copyright 1993 by OpenVision Technologies, Inc. 14 * 15 * Permission to use, copy, modify, distribute, and sell this software 16 * and its documentation for any purpose is hereby granted without fee, 17 * provided that the above copyright notice appears in all copies and 18 * that both that copyright notice and this permission notice appear in 19 * supporting documentation, and that the name of OpenVision not be used 20 * in advertising or publicity pertaining to distribution of the software 21 * without specific, written prior permission. OpenVision makes no 22 * representations about the suitability of this software for any 23 * purpose. It is provided "as is" without express or implied warranty. 24 * 25 * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, 26 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO 27 * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR 28 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF 29 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR 30 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 31 * PERFORMANCE OF THIS SOFTWARE. 32 */ 33 34#include <linux/types.h> 35#include <linux/module.h> 36#include <linux/string.h> 37#include <linux/sunrpc/sched.h> 38#include <linux/sunrpc/gss_asn1.h> 39 40 41#ifdef RPC_DEBUG 42# define RPCDBG_FACILITY RPCDBG_AUTH 43#endif 44 45 46/* TWRITE_STR from gssapiP_generic.h */ 47#define TWRITE_STR(ptr, str, len) \ 48 memcpy((ptr), (char *) (str), (len)); \ 49 (ptr) += (len); 50 51 52/* Each token looks like this: 53 540x60 tag for APPLICATION 0, SEQUENCE 55 (constructed, definite-length) 56 <length> possible multiple bytes, need to parse/generate 57 0x06 tag for OBJECT IDENTIFIER 58 <moid_length> compile-time constant string (assume 1 byte) 59 <moid_bytes> compile-time constant string 60 <inner_bytes> the ANY containing the application token 61 bytes 0,1 are the token type 62 bytes 2,n are the token data 63 64For the purposes of this abstraction, the token "header" consists of 65the sequence tag and length octets, the mech OID DER encoding, and the 66first two inner bytes, which indicate the token type. The token 67"body" consists of everything else. 68 69*/ 70 71static int 72der_length_size( int length) 73{ 74 if (length < (1<<7)) 75 return(1); 76 else if (length < (1<<8)) 77 return(2); 78#if (SIZEOF_INT == 2) 79 else 80 return(3); 81#else 82 else if (length < (1<<16)) 83 return(3); 84 else if (length < (1<<24)) 85 return(4); 86 else 87 return(5); 88#endif 89} 90 91static void 92der_write_length(unsigned char **buf, int length) 93{ 94 if (length < (1<<7)) { 95 *(*buf)++ = (unsigned char) length; 96 } else { 97 *(*buf)++ = (unsigned char) (der_length_size(length)+127); 98#if (SIZEOF_INT > 2) 99 if (length >= (1<<24)) 100 *(*buf)++ = (unsigned char) (length>>24); 101 if (length >= (1<<16)) 102 *(*buf)++ = (unsigned char) ((length>>16)&0xff); 103#endif 104 if (length >= (1<<8)) 105 *(*buf)++ = (unsigned char) ((length>>8)&0xff); 106 *(*buf)++ = (unsigned char) (length&0xff); 107 } 108} 109 110/* returns decoded length, or < 0 on failure. Advances buf and 111 decrements bufsize */ 112 113static int 114der_read_length(unsigned char **buf, int *bufsize) 115{ 116 unsigned char sf; 117 int ret; 118 119 if (*bufsize < 1) 120 return(-1); 121 sf = *(*buf)++; 122 (*bufsize)--; 123 if (sf & 0x80) { 124 if ((sf &= 0x7f) > ((*bufsize)-1)) 125 return(-1); 126 if (sf > SIZEOF_INT) 127 return (-1); 128 ret = 0; 129 for (; sf; sf--) { 130 ret = (ret<<8) + (*(*buf)++); 131 (*bufsize)--; 132 } 133 } else { 134 ret = sf; 135 } 136 137 return(ret); 138} 139 140/* returns the length of a token, given the mech oid and the body size */ 141 142int 143g_token_size(struct xdr_netobj *mech, unsigned int body_size) 144{ 145 /* set body_size to sequence contents size */ 146 body_size += 2 + (int) mech->len; /* NEED overflow check */ 147 return(1 + der_length_size(body_size) + body_size); 148} 149 150EXPORT_SYMBOL_GPL(g_token_size); 151 152/* fills in a buffer with the token header. The buffer is assumed to 153 be the right size. buf is advanced past the token header */ 154 155void 156g_make_token_header(struct xdr_netobj *mech, int body_size, unsigned char **buf) 157{ 158 *(*buf)++ = 0x60; 159 der_write_length(buf, 2 + mech->len + body_size); 160 *(*buf)++ = 0x06; 161 *(*buf)++ = (unsigned char) mech->len; 162 TWRITE_STR(*buf, mech->data, ((int) mech->len)); 163} 164 165EXPORT_SYMBOL_GPL(g_make_token_header); 166 167/* 168 * Given a buffer containing a token, reads and verifies the token, 169 * leaving buf advanced past the token header, and setting body_size 170 * to the number of remaining bytes. Returns 0 on success, 171 * G_BAD_TOK_HEADER for a variety of errors, and G_WRONG_MECH if the 172 * mechanism in the token does not match the mech argument. buf and 173 * *body_size are left unmodified on error. 174 */ 175u32 176g_verify_token_header(struct xdr_netobj *mech, int *body_size, 177 unsigned char **buf_in, int toksize) 178{ 179 unsigned char *buf = *buf_in; 180 int seqsize; 181 struct xdr_netobj toid; 182 int ret = 0; 183 184 if ((toksize-=1) < 0) 185 return(G_BAD_TOK_HEADER); 186 if (*buf++ != 0x60) 187 return(G_BAD_TOK_HEADER); 188 189 if ((seqsize = der_read_length(&buf, &toksize)) < 0) 190 return(G_BAD_TOK_HEADER); 191 192 if (seqsize != toksize) 193 return(G_BAD_TOK_HEADER); 194 195 if ((toksize-=1) < 0) 196 return(G_BAD_TOK_HEADER); 197 if (*buf++ != 0x06) 198 return(G_BAD_TOK_HEADER); 199 200 if ((toksize-=1) < 0) 201 return(G_BAD_TOK_HEADER); 202 toid.len = *buf++; 203 204 if ((toksize-=toid.len) < 0) 205 return(G_BAD_TOK_HEADER); 206 toid.data = buf; 207 buf+=toid.len; 208 209 if (! g_OID_equal(&toid, mech)) 210 ret = G_WRONG_MECH; 211 212 /* G_WRONG_MECH is not returned immediately because it's more important 213 to return G_BAD_TOK_HEADER if the token header is in fact bad */ 214 215 if ((toksize-=2) < 0) 216 return(G_BAD_TOK_HEADER); 217 218 if (ret) 219 return(ret); 220 221 if (!ret) { 222 *buf_in = buf; 223 *body_size = toksize; 224 } 225 226 return(ret); 227} 228 229EXPORT_SYMBOL_GPL(g_verify_token_header); 230