1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2008 Doug Rabson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 #include <gssapi/gssapi.h> 32 #include <stdlib.h> 33 #include <string.h> 34 35 #include "utils.h" 36 37 OM_uint32 38 gss_decapsulate_token(const gss_buffer_t input_token, gss_OID oid, 39 gss_buffer_t output_token) 40 { 41 unsigned char *p = input_token->value; 42 size_t len = input_token->length; 43 size_t a, b; 44 gss_OID_desc mech_oid; 45 46 _gss_buffer_zero(output_token); 47 48 /* 49 * Token must start with [APPLICATION 0] SEQUENCE. 50 */ 51 if (len == 0 || *p != 0x60) 52 return (GSS_S_DEFECTIVE_TOKEN); 53 p++; 54 len--; 55 56 /* 57 * Decode the length and make sure it agrees with the 58 * token length. 59 */ 60 if (len == 0) 61 return (GSS_S_DEFECTIVE_TOKEN); 62 if ((*p & 0x80) == 0) { 63 a = *p; 64 p++; 65 len--; 66 } else { 67 b = *p & 0x7f; 68 p++; 69 len--; 70 if (len < b) 71 return (GSS_S_DEFECTIVE_TOKEN); 72 a = 0; 73 while (b) { 74 a = (a << 8) | *p; 75 p++; 76 len--; 77 b--; 78 } 79 } 80 if (a != len) 81 return (GSS_S_DEFECTIVE_TOKEN); 82 83 /* 84 * Decode the OID for the mechanism. Simplify life by 85 * assuming that the OID length is less than 128 bytes. 86 */ 87 if (len < 2 || *p != 0x06) 88 return (GSS_S_DEFECTIVE_TOKEN); 89 if ((p[1] & 0x80) || p[1] > (len - 2)) 90 return (GSS_S_DEFECTIVE_TOKEN); 91 mech_oid.length = p[1]; 92 p += 2; 93 len -= 2; 94 mech_oid.elements = p; 95 96 if (!gss_oid_equal(&mech_oid, oid)) 97 return (GSS_S_FAILURE); 98 99 p += mech_oid.length; 100 len -= mech_oid.length; 101 102 output_token->length = len; 103 output_token->value = malloc(len); 104 if (!output_token->value) 105 return (GSS_S_DEFECTIVE_TOKEN); 106 memcpy(output_token->value, p, len); 107 108 return (GSS_S_COMPLETE); 109 } 110