1 /*- 2 * Copyright (c) 2008 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <gssapi/gssapi.h> 30 #include <stdlib.h> 31 #include <string.h> 32 33 #include "utils.h" 34 35 OM_uint32 36 gss_decapsulate_token(const gss_buffer_t input_token, gss_OID oid, 37 gss_buffer_t output_token) 38 { 39 unsigned char *p = input_token->value; 40 size_t len = input_token->length; 41 size_t a, b; 42 gss_OID_desc mech_oid; 43 44 _gss_buffer_zero(output_token); 45 46 /* 47 * Token must start with [APPLICATION 0] SEQUENCE. 48 */ 49 if (len == 0 || *p != 0x60) 50 return (GSS_S_DEFECTIVE_TOKEN); 51 p++; 52 len--; 53 54 /* 55 * Decode the length and make sure it agrees with the 56 * token length. 57 */ 58 if (len == 0) 59 return (GSS_S_DEFECTIVE_TOKEN); 60 if ((*p & 0x80) == 0) { 61 a = *p; 62 p++; 63 len--; 64 } else { 65 b = *p & 0x7f; 66 p++; 67 len--; 68 if (len < b) 69 return (GSS_S_DEFECTIVE_TOKEN); 70 a = 0; 71 while (b) { 72 a = (a << 8) | *p; 73 p++; 74 len--; 75 b--; 76 } 77 } 78 if (a != len) 79 return (GSS_S_DEFECTIVE_TOKEN); 80 81 /* 82 * Decode the OID for the mechanism. Simplify life by 83 * assuming that the OID length is less than 128 bytes. 84 */ 85 if (len < 2 || *p != 0x06) 86 return (GSS_S_DEFECTIVE_TOKEN); 87 if ((p[1] & 0x80) || p[1] > (len - 2)) 88 return (GSS_S_DEFECTIVE_TOKEN); 89 mech_oid.length = p[1]; 90 p += 2; 91 len -= 2; 92 mech_oid.elements = p; 93 94 if (!gss_oid_equal(&mech_oid, oid)) 95 return (GSS_S_FAILURE); 96 97 p += mech_oid.length; 98 len -= mech_oid.length; 99 100 output_token->length = len; 101 output_token->value = malloc(len); 102 if (!output_token->value) 103 return (GSS_S_DEFECTIVE_TOKEN); 104 memcpy(output_token->value, p, len); 105 106 return (GSS_S_COMPLETE); 107 } 108