1 /* 2 * Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 #include <stdio.h> 11 #include "internal/cryptlib.h" 12 #include <openssl/asn1t.h> 13 14 #if !(OPENSSL_API_COMPAT < 0x10200000L) 15 NON_EMPTY_TRANSLATION_UNIT 16 #else 17 18 #define COPY_SIZE(a, b) (sizeof(a) < sizeof(b) ? sizeof(a) : sizeof(b)) 19 20 /* 21 * Custom primitive type for long handling. This converts between an 22 * ASN1_INTEGER and a long directly. 23 */ 24 25 static int long_new(ASN1_VALUE **pval, const ASN1_ITEM *it); 26 static void long_free(ASN1_VALUE **pval, const ASN1_ITEM *it); 27 28 static int long_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype, 29 const ASN1_ITEM *it); 30 static int long_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len, 31 int utype, char *free_cont, const ASN1_ITEM *it); 32 static int long_print(BIO *out, ASN1_VALUE **pval, const ASN1_ITEM *it, 33 int indent, const ASN1_PCTX *pctx); 34 35 static ASN1_PRIMITIVE_FUNCS long_pf = { 36 NULL, 0, 37 long_new, 38 long_free, 39 long_free, /* Clear should set to initial value */ 40 long_c2i, 41 long_i2c, 42 long_print 43 }; 44 45 ASN1_ITEM_start(LONG) 46 ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &long_pf, ASN1_LONG_UNDEF, "LONG" 47 ASN1_ITEM_end(LONG) 48 49 ASN1_ITEM_start(ZLONG) 50 ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &long_pf, 0, "ZLONG" 51 ASN1_ITEM_end(ZLONG) 52 53 static int long_new(ASN1_VALUE **pval, const ASN1_ITEM *it) 54 { 55 memcpy(pval, &it->size, COPY_SIZE(*pval, it->size)); 56 return 1; 57 } 58 59 static void long_free(ASN1_VALUE **pval, const ASN1_ITEM *it) 60 { 61 memcpy(pval, &it->size, COPY_SIZE(*pval, it->size)); 62 } 63 64 /* 65 * Originally BN_num_bits_word was called to perform this operation, but 66 * trouble is that there is no guarantee that sizeof(long) equals to 67 * sizeof(BN_ULONG). BN_ULONG is a configurable type that can be as wide 68 * as long, but also double or half... 69 */ 70 static int num_bits_ulong(unsigned long value) 71 { 72 size_t i; 73 unsigned long ret = 0; 74 75 /* 76 * It is argued that *on average* constant counter loop performs 77 * not worse [if not better] than one with conditional break or 78 * mask-n-table-lookup-style, because of branch misprediction 79 * penalties. 80 */ 81 for (i = 0; i < sizeof(value) * 8; i++) { 82 ret += (value != 0); 83 value >>= 1; 84 } 85 86 return (int)ret; 87 } 88 89 static int long_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype, 90 const ASN1_ITEM *it) 91 { 92 long ltmp; 93 unsigned long utmp, sign; 94 int clen, pad, i; 95 96 memcpy(<mp, pval, COPY_SIZE(*pval, ltmp)); 97 if (ltmp == it->size) 98 return -1; 99 /* 100 * Convert the long to positive: we subtract one if negative so we can 101 * cleanly handle the padding if only the MSB of the leading octet is 102 * set. 103 */ 104 if (ltmp < 0) { 105 sign = 0xff; 106 utmp = 0 - (unsigned long)ltmp - 1; 107 } else { 108 sign = 0; 109 utmp = ltmp; 110 } 111 clen = num_bits_ulong(utmp); 112 /* If MSB of leading octet set we need to pad */ 113 if (!(clen & 0x7)) 114 pad = 1; 115 else 116 pad = 0; 117 118 /* Convert number of bits to number of octets */ 119 clen = (clen + 7) >> 3; 120 121 if (cont != NULL) { 122 if (pad) 123 *cont++ = (unsigned char)sign; 124 for (i = clen - 1; i >= 0; i--) { 125 cont[i] = (unsigned char)(utmp ^ sign); 126 utmp >>= 8; 127 } 128 } 129 return clen + pad; 130 } 131 132 static int long_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len, 133 int utype, char *free_cont, const ASN1_ITEM *it) 134 { 135 int i; 136 long ltmp; 137 unsigned long utmp = 0, sign = 0x100; 138 139 if (len > 1) { 140 /* 141 * Check possible pad byte. Worst case, we're skipping past actual 142 * content, but since that's only with 0x00 and 0xff and we set neg 143 * accordingly, the result will be correct in the end anyway. 144 */ 145 switch (cont[0]) { 146 case 0xff: 147 cont++; 148 len--; 149 sign = 0xff; 150 break; 151 case 0: 152 cont++; 153 len--; 154 sign = 0; 155 break; 156 } 157 } 158 if (len > (int)sizeof(long)) { 159 ASN1err(ASN1_F_LONG_C2I, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG); 160 return 0; 161 } 162 163 if (sign == 0x100) { 164 /* Is it negative? */ 165 if (len && (cont[0] & 0x80)) 166 sign = 0xff; 167 else 168 sign = 0; 169 } else if (((sign ^ cont[0]) & 0x80) == 0) { /* same sign bit? */ 170 ASN1err(ASN1_F_LONG_C2I, ASN1_R_ILLEGAL_PADDING); 171 return 0; 172 } 173 utmp = 0; 174 for (i = 0; i < len; i++) { 175 utmp <<= 8; 176 utmp |= cont[i] ^ sign; 177 } 178 ltmp = (long)utmp; 179 if (ltmp < 0) { 180 ASN1err(ASN1_F_LONG_C2I, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG); 181 return 0; 182 } 183 if (sign) 184 ltmp = -ltmp - 1; 185 if (ltmp == it->size) { 186 ASN1err(ASN1_F_LONG_C2I, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG); 187 return 0; 188 } 189 memcpy(pval, <mp, COPY_SIZE(*pval, ltmp)); 190 return 1; 191 } 192 193 static int long_print(BIO *out, ASN1_VALUE **pval, const ASN1_ITEM *it, 194 int indent, const ASN1_PCTX *pctx) 195 { 196 long l; 197 198 memcpy(&l, pval, COPY_SIZE(*pval, l)); 199 return BIO_printf(out, "%ld\n", l); 200 } 201 #endif 202