diff options
| -rw-r--r-- | crypto/bn/bn_lib.c | 128 | ||||
| -rw-r--r-- | doc/man3/BN_bn2bin.pod | 42 | ||||
| -rw-r--r-- | include/openssl/bn.h | 6 | ||||
| -rw-r--r-- | util/libcrypto.num | 6 |
4 files changed, 150 insertions, 32 deletions
diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c index a08286cab1..9b19a7243c 100644 --- a/crypto/bn/bn_lib.c +++ b/crypto/bn/bn_lib.c @@ -431,13 +431,15 @@ int BN_set_word(BIGNUM *a, BN_ULONG w) } typedef enum {BIG, LITTLE} endianess_t; +typedef enum {SIGNED, UNSIGNED} signedness_t; static BIGNUM *bin2bn(const unsigned char *s, int len, BIGNUM *ret, - endianess_t endianess) + endianess_t endianess, signedness_t signedness) { int inc; const unsigned char *s2; int inc2; + int neg = 0, xor = 0, carry = 0; unsigned int i; unsigned int n; BIGNUM *bn = NULL; @@ -467,13 +469,30 @@ static BIGNUM *bin2bn(const unsigned char *s, int len, BIGNUM *ret, break; } + /* Take note of the signedness of the input bytes*/ + if (signedness == SIGNED) { + neg = !!(*s2 & 0x80); + xor = neg ? 0xff : 0x00; + carry = neg; + } + /* - * Skip leading sign extensions (zero for unsigned numbers). + * Skip leading sign extensions (the value of |xor|). * This is the only spot where |s2| and |inc2| are used. */ for ( ; len > 0 && *s2 == xor; s2 += inc2, len--) continue; + /* + * If there was a set of 0xff, we backtrack one byte unless the next + * one has a sign bit, as the last 0xff is then part of the actual + * number, rather then a mere sign extension. + */ + if (xor == 0xff) { + if (len == 0 || !(*s2 & 0x80)) + len++; + } + /* If it was all zeros, we're done */ if (len == 0) { ret->top = 0; return ret; @@ -484,14 +503,16 @@ static BIGNUM *bin2bn(const unsigned char *s, int len, BIGNUM *ret, return NULL; } ret->top = n; - ret->neg = 0; + ret->neg = neg; for (i = 0; n-- > 0; i++) { BN_ULONG l = 0; /* Accumulator */ unsigned int m = 0; /* Offset in a bignum chunk, in bits */ for (; len > 0 && m < BN_BYTES * 8; len--, s += inc, m += 8) { - BN_ULONG byte = *s; + BN_ULONG byte_xored = *s ^ xor; + BN_ULONG byte = (byte_xored + carry) & 0xff; + carry = byte_xored > byte; /* Implicit 1 or 0 */ l |= (byte << m); } ret->d[i] = l; @@ -506,33 +527,56 @@ static BIGNUM *bin2bn(const unsigned char *s, int len, BIGNUM *ret, BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret) { - return bin2bn(s, len, ret, BIG); + return bin2bn(s, len, ret, BIG, UNSIGNED); } -/* ignore negative */ -static -int bn2binpad(const BIGNUM *a, unsigned char *to, int tolen, - endianess_t endianess) +BIGNUM *BN_signed_bin2bn(const unsigned char *s, int len, BIGNUM *ret) +{ + return bin2bn(s, len, ret, BIG, SIGNED); +} + +static int bn2binpad(const BIGNUM *a, unsigned char *to, int tolen, + endianess_t endianess, signedness_t signedness) { int inc; - int n; + int n, n8; + int xor = 0, carry = 0, ext = 0; size_t i, lasti, j, atop, mask; BN_ULONG l; /* - * In case |a| is fixed-top, BN_num_bytes can return bogus length, + * In case |a| is fixed-top, BN_num_bits can return bogus length, * but it's assumed that fixed-top inputs ought to be "nominated" * even for padded output, so it works out... */ - n = BN_num_bytes(a); + n8 = BN_num_bits(a); + n = (n8 + 7) / 8; /* This is what BN_num_bytes() does */ + + /* Take note of the signedness of the bignum */ + if (signedness == SIGNED) { + xor = a->neg ? 0xff : 0x00; + carry = a->neg; + + /* + * if |n * 8 == n|, then the MSbit is set, otherwise unset. + * We must compensate with one extra byte if that doesn't + * correspond to the signedness of the bignum with regards + * to 2's complement. + */ + ext = (n * 8 == n8) + ? !a->neg /* MSbit set on nonnegative bignum */ + : a->neg; /* MSbit unset on negative bignum */ + } + if (tolen == -1) { - tolen = n; - } else if (tolen < n) { /* uncommon/unlike case */ + tolen = n + ext; + } else if (tolen < n + ext) { /* uncommon/unlike case */ BIGNUM temp = *a; bn_correct_top(&temp); - n = BN_num_bytes(&temp); - if (tolen < n) + n8 = BN_num_bits(&temp); + n = (n8 + 7) / 8; /* This is what BN_num_bytes() does */ + if (tolen < n + ext) return -1; } @@ -562,9 +606,14 @@ int bn2binpad(const BIGNUM *a, unsigned char *to, int tolen, lasti = atop - 1; atop = a->top * BN_BYTES; for (i = 0, j = 0; j < (size_t)tolen; j++) { + unsigned char byte, byte_xored; + l = a->d[i / BN_BYTES]; mask = 0 - ((j - atop) >> (8 * sizeof(i) - 1)); - *to = (unsigned char)(l >> (8 * (i % BN_BYTES)) & mask); + byte = (unsigned char)(l >> (8 * (i % BN_BYTES)) & mask); + byte_xored = byte ^ xor; + *to = (unsigned char)(byte_xored + carry); + carry = byte_xored > *to; /* Implicit 1 or 0 */ to += inc; i += (i - lasti) >> (8 * sizeof(i) - 1); /* stay on last limb */ } @@ -576,24 +625,43 @@ int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen) { if (tolen < 0) return -1; - return bn2binpad(a, to, tolen, BIG); + return bn2binpad(a, to, tolen, BIG, UNSIGNED); +} + +int BN_signed_bn2bin(const BIGNUM *a, unsigned char *to, int tolen) +{ + if (tolen < 0) + return -1; + return bn2binpad(a, to, tolen, BIG, SIGNED); } int BN_bn2bin(const BIGNUM *a, unsigned char *to) { - return bn2binpad(a, to, -1, BIG); + return bn2binpad(a, to, -1, BIG, UNSIGNED); } BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret) { - return bin2bn(s, len, ret, LITTLE); + return bin2bn(s, len, ret, LITTLE, UNSIGNED); +} + +BIGNUM *BN_signed_lebin2bn(const unsigned char *s, int len, BIGNUM *ret) +{ + return bin2bn(s, len, ret, LITTLE, SIGNED); } int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen) { if (tolen < 0) return -1; - return bn2binpad(a, to, tolen, LITTLE); + return bn2binpad(a, to, tolen, LITTLE, UNSIGNED); +} + +int BN_signed_bn2lebin(const BIGNUM *a, unsigned char *to, int tolen) +{ + if (tolen < 0) + return -1; + return bn2binpad(a, to, tolen, LITTLE, SIGNED); } BIGNUM *BN_native2bn(const unsigned char *s, int len, BIGNUM *ret) @@ -605,6 +673,15 @@ BIGNUM *BN_native2bn(const unsigned char *s, int len, BIGNUM *ret) return BN_bin2bn(s, len, ret); } +BIGNUM *BN_signed_native2bn(const unsigned char *s, int len, BIGNUM *ret) +{ + DECLARE_IS_ENDIAN; + + if (IS_LITTLE_ENDIAN) + return BN_signed_lebin2bn(s, len, ret); + return BN_signed_bin2bn(s, len, ret); +} + int BN_bn2nativepad(const BIGNUM *a, unsigned char *to, int tolen) { DECLARE_IS_ENDIAN; @@ -614,6 +691,15 @@ int BN_bn2nativepad(const BIGNUM *a, unsigned char *to, int tolen) return BN_bn2binpad(a, to, tolen); } +int BN_signed_bn2native(const BIGNUM *a, unsigned char *to, int tolen) +{ + DECLARE_IS_ENDIAN; + + if (IS_LITTLE_ENDIAN) + return BN_signed_bn2lebin(a, to, tolen); + return BN_signed_bn2bin(a, to, tolen); +} + int BN_ucmp(const BIGNUM *a, const BIGNUM *b) { int i; diff --git a/doc/man3/BN_bn2bin.pod b/doc/man3/BN_bn2bin.pod index e75b9fffb5..3e5f2deeca 100644 --- a/doc/man3/BN_bn2bin.pod +++ b/doc/man3/BN_bn2bin.pod @@ -2,9 +2,10 @@ =head1 NAME -BN_bn2binpad, -BN_bn2bin, BN_bin2bn, BN_bn2lebinpad, BN_lebin2bn, -BN_bn2nativepad, BN_native2bn, BN_bn2hex, BN_bn2dec, BN_hex2bn, BN_dec2bn, +BN_bn2binpad, BN_signed_bn2bin, BN_bn2bin, BN_bin2bn, BN_signed_bin2bn, +BN_bn2lebinpad, BN_signed_bn2lebin, BN_lebin2bn, BN_signed_lebin2bn, +BN_bn2nativepad, BN_signed_bn2native, BN_native2bn, BN_signed_native2bn, +BN_bn2hex, BN_bn2dec, BN_hex2bn, BN_dec2bn, BN_print, BN_print_fp, BN_bn2mpi, BN_mpi2bn - format conversions =head1 SYNOPSIS @@ -13,13 +14,19 @@ BN_print, BN_print_fp, BN_bn2mpi, BN_mpi2bn - format conversions int BN_bn2bin(const BIGNUM *a, unsigned char *to); int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen); + int BN_signed_bn2bin(const BIGNUM *a, unsigned char *to, int tolen); BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret); + BIGNUM *BN_signed_bin2bn(const unsigned char *s, int len, BIGNUM *ret); int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen); + int BN_signed_bn2lebin(const BIGNUM *a, unsigned char *to, int tolen); BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret); + BIGNUM *BN_signed_lebin2bn(const unsigned char *s, int len, BIGNUM *ret); int BN_bn2nativepad(const BIGNUM *a, unsigned char *to, int tolen); + int BN_signed_bn2native(const BIGNUM *a, unsigned char *to, int tolen); BIGNUM *BN_native2bn(const unsigned char *s, int len, BIGNUM *ret); + BIGNUM *BN_signed_native2bn(const unsigned char *s, int len, BIGNUM *ret); char *BN_bn2hex(const BIGNUM *a); char *BN_bn2dec(const BIGNUM *a); @@ -43,17 +50,29 @@ and stores it at B<to>. B<tolen> indicates the length of the output buffer B<to>. The result is padded with zeros if necessary. If B<tolen> is less than BN_num_bytes(B<a>) an error is returned. +BN_signed_bn2bin() converts the value of B<a> into big-endian signed 2's +complements form and stores it at B<to>. B<tolen> indicates the length of +the output buffer B<to>. The result is signed extended (padded with 0x00 +for positive numbers or with 0xff for negative numbers) if necessary. +If B<tolen> is smaller than the necessary size (which may be +C<<BN_num_bytes(B<a>) + 1>>), an error is returned. + BN_bin2bn() converts the positive integer in big-endian form of length B<len> at B<s> into a B<BIGNUM> and places it in B<ret>. If B<ret> is NULL, a new B<BIGNUM> is created. -BN_bn2lebinpad() and BN_lebin2bn() are identical to BN_bn2binpad() and -BN_bin2bn() except the buffer is in little-endian format. +BN_signed_bin2bn() converts the integer in big-endian signed 2's complement +form of length B<len> at B<s> into a B<BIGNUM> and places it in B<ret>. If +B<ret> is NULL, a new B<BIGNUM> is created. + +BN_bn2lebinpad(), BN_signed_bn2lebin() and BN_lebin2bn() are identical to +BN_bn2binpad(), BN_signed_bn2bin() and BN_bin2bn() except the buffer is in +little-endian format. -BN_bn2nativepad() and BN_native2bn() are identical to BN_bn2binpad() and -BN_bin2bn() except the buffer is in native format, i.e. most significant -byte first on big-endian platforms, and least significant byte first on -little-endian platforms. +BN_bn2nativepad(), BN_signed_bn2native() and BN_native2bn() are identical +to BN_bn2binpad(), BN_signed_bn2bin() and BN_bin2bn() except the buffer is +in native format, i.e. most significant byte first on big-endian platforms, +and least significant byte first on little-endian platforms. BN_bn2hex() and BN_bn2dec() return printable strings containing the hexadecimal and decimal encoding of B<a> respectively. For negative @@ -91,8 +110,9 @@ if B<ret> is NULL. BN_bn2bin() returns the length of the big-endian number placed at B<to>. BN_bin2bn() returns the B<BIGNUM>, NULL on error. -BN_bn2binpad(), BN_bn2lebinpad(), and BN_bn2nativepad() return the number of bytes written or -1 if the supplied -buffer is too small. +BN_bn2binpad(), BN_signed_bn2bin(), BN_bn2lebinpad(), BN_signed_bn2lebin(), +BN_bn2nativepad(), and_signed BN_bn2native() return the number of bytes +written or -1 if the supplied buffer is too small. BN_bn2hex() and BN_bn2dec() return a NUL-terminated string, or NULL on error. BN_hex2bn() and BN_dec2bn() return the number of characters diff --git a/include/openssl/bn.h b/include/openssl/bn.h index ecd7f01b9b..f80aad6cde 100644 --- a/include/openssl/bn.h +++ b/include/openssl/bn.h @@ -241,12 +241,18 @@ void BN_clear_free(BIGNUM *a); BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b); void BN_swap(BIGNUM *a, BIGNUM *b); BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret); +BIGNUM *BN_signed_bin2bn(const unsigned char *s, int len, BIGNUM *ret); int BN_bn2bin(const BIGNUM *a, unsigned char *to); int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen); +int BN_signed_bn2bin(const BIGNUM *a, unsigned char *to, int tolen); BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret); +BIGNUM *BN_signed_lebin2bn(const unsigned char *s, int len, BIGNUM *ret); int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen); +int BN_signed_bn2lebin(const BIGNUM *a, unsigned char *to, int tolen); BIGNUM *BN_native2bn(const unsigned char *s, int len, BIGNUM *ret); +BIGNUM *BN_signed_native2bn(const unsigned char *s, int len, BIGNUM *ret); int BN_bn2nativepad(const BIGNUM *a, unsigned char *to, int tolen); +int BN_signed_bn2native(const BIGNUM *a, unsigned char *to, int tolen); BIGNUM *BN_mpi2bn(const unsigned char *s, int len, BIGNUM *ret); int BN_bn2mpi(const BIGNUM *a, unsigned char *to); int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b); diff --git a/util/libcrypto.num b/util/libcrypto.num index 762e23a858..7b63154b55 100644 --- a/util/libcrypto.num +++ b/util/libcrypto.num @@ -5428,3 +5428,9 @@ EVP_PKEY_CTX_get0_provider 5555 3_0_0 EXIST::FUNCTION: OSSL_STACK_OF_X509_free ? 3_1_0 EXIST::FUNCTION: EVP_MD_CTX_dup ? 3_1_0 EXIST::FUNCTION: EVP_CIPHER_CTX_dup ? 3_1_0 EXIST::FUNCTION: +BN_signed_bin2bn ? 3_1_0 EXIST::FUNCTION: +BN_signed_bn2bin ? 3_1_0 EXIST::FUNCTION: +BN_signed_lebin2bn ? 3_1_0 EXIST::FUNCTION: +BN_signed_bn2lebin ? 3_1_0 EXIST::FUNCTION: +BN_signed_native2bn ? 3_1_0 EXIST::FUNCTION: +BN_signed_bn2native ? 3_1_0 EXIST::FUNCTION: |