/*
* Copyright (c) 2016 Thomas Pornin
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef INNER_H__
#define INNER_H__
#include
#include
#include "config.h"
#include "bearssl.h"
/*
* On MSVC, disable the warning about applying unary minus on an
* unsigned type: it is standard, we do it all the time, and for
* good reasons.
*/
#if _MSC_VER
#pragma warning( disable : 4146 )
#endif
/*
* Maximum size for a RSA modulus (in bits). Allocated stack buffers
* depend on that size, so this value should be kept small. Currently,
* 2048-bit RSA keys offer adequate security, and should still do so for
* the next few decades; however, a number of widespread PKI have
* already set their root keys to RSA-4096, so we should be able to
* process such keys.
*
* This value MUST be a multiple of 64.
*/
#define BR_MAX_RSA_SIZE 4096
/*
* Maximum size for a RSA factor (in bits). This is for RSA private-key
* operations. Default is to support factors up to a bit more than half
* the maximum modulus size.
*
* This value MUST be a multiple of 32.
*/
#define BR_MAX_RSA_FACTOR ((BR_MAX_RSA_SIZE + 64) >> 1)
/*
* Maximum size for an EC curve (modulus or order), in bits. Size of
* stack buffers depends on that parameter. This size MUST be a multiple
* of 8 (so that decoding an integer with that many bytes does not
* overflow).
*/
#define BR_MAX_EC_SIZE 528
/*
* Some macros to recognize the current architecture. Right now, we are
* interested into automatically recognizing architecture with efficient
* 64-bit types so that we may automatically use implementations that
* use 64-bit registers in that case. Future versions may detect, e.g.,
* availability of SSE2 intrinsics.
*
* If 'unsigned long' is a 64-bit type, then we assume that 64-bit types
* are efficient. Otherwise, we rely on macros that depend on compiler,
* OS and architecture. In any case, failure to detect the architecture
* as 64-bit means that the 32-bit code will be used, and that code
* works also on 64-bit architectures (the 64-bit code may simply be
* more efficient).
*
* The test on 'unsigned long' should already catch most cases, the one
* notable exception being Windows code where 'unsigned long' is kept to
* 32-bit for compatbility with all the legacy code that liberally uses
* the 'DWORD' type for 32-bit values.
*
* Macro names are taken from: http://nadeausoftware.com/articles/2012/02/c_c_tip_how_detect_processor_type_using_compiler_predefined_macros
*/
#ifndef BR_64
#if ((ULONG_MAX >> 31) >> 31) == 3
#define BR_64 1
#elif defined(__ia64) || defined(__itanium__) || defined(_M_IA64)
#define BR_64 1
#elif defined(__powerpc64__) || defined(__ppc64__) || defined(__PPC64__) \
|| defined(__64BIT__) || defined(_LP64) || defined(__LP64__)
#define BR_64 1
#elif defined(__sparc64__)
#define BR_64 1
#elif defined(__x86_64__) || defined(_M_X64)
#define BR_64 1
#endif
#endif
/* ==================================================================== */
/*
* Encoding/decoding functions.
*
* 32-bit and 64-bit decoding, both little-endian and big-endian, is
* implemented with the inline functions below. These functions are
* generic: they don't depend on the architecture natural endianness,
* and they can handle unaligned accesses. Optimized versions for some
* specific architectures may be implemented at a later time.
*/
static inline void
br_enc16le(void *dst, unsigned x)
{
unsigned char *buf;
buf = dst;
buf[0] = (unsigned char)x;
buf[1] = (unsigned char)(x >> 8);
}
static inline void
br_enc16be(void *dst, unsigned x)
{
unsigned char *buf;
buf = dst;
buf[0] = (unsigned char)(x >> 8);
buf[1] = (unsigned char)x;
}
static inline unsigned
br_dec16le(const void *src)
{
const unsigned char *buf;
buf = src;
return (unsigned)buf[0] | ((unsigned)buf[1] << 8);
}
static inline unsigned
br_dec16be(const void *src)
{
const unsigned char *buf;
buf = src;
return ((unsigned)buf[0] << 8) | (unsigned)buf[1];
}
static inline void
br_enc32le(void *dst, uint32_t x)
{
unsigned char *buf;
buf = dst;
buf[0] = (unsigned char)x;
buf[1] = (unsigned char)(x >> 8);
buf[2] = (unsigned char)(x >> 16);
buf[3] = (unsigned char)(x >> 24);
}
static inline void
br_enc32be(void *dst, uint32_t x)
{
unsigned char *buf;
buf = dst;
buf[0] = (unsigned char)(x >> 24);
buf[1] = (unsigned char)(x >> 16);
buf[2] = (unsigned char)(x >> 8);
buf[3] = (unsigned char)x;
}
static inline uint32_t
br_dec32le(const void *src)
{
const unsigned char *buf;
buf = src;
return (uint32_t)buf[0]
| ((uint32_t)buf[1] << 8)
| ((uint32_t)buf[2] << 16)
| ((uint32_t)buf[3] << 24);
}
static inline uint32_t
br_dec32be(const void *src)
{
const unsigned char *buf;
buf = src;
return ((uint32_t)buf[0] << 24)
| ((uint32_t)buf[1] << 16)
| ((uint32_t)buf[2] << 8)
| (uint32_t)buf[3];
}
static inline void
br_enc64le(void *dst, uint64_t x)
{
unsigned char *buf;
buf = dst;
br_enc32le(buf, (uint32_t)x);
br_enc32le(buf + 4, (uint32_t)(x >> 32));
}
static inline void
br_enc64be(void *dst, uint64_t x)
{
unsigned char *buf;
buf = dst;
br_enc32be(buf, (uint32_t)(x >> 32));
br_enc32be(buf + 4, (uint32_t)x);
}
static inline uint64_t
br_dec64le(const void *src)
{
const unsigned char *buf;
buf = src;
return (uint64_t)br_dec32le(buf)
| ((uint64_t)br_dec32le(buf + 4) << 32);
}
static inline uint64_t
br_dec64be(const void *src)
{
const unsigned char *buf;
buf = src;
return ((uint64_t)br_dec32be(buf) << 32)
| (uint64_t)br_dec32be(buf + 4);
}
/*
* Range decoding and encoding (for several successive values).
*/
void br_range_dec16le(uint16_t *v, size_t num, const void *src);
void br_range_dec16be(uint16_t *v, size_t num, const void *src);
void br_range_enc16le(void *dst, const uint16_t *v, size_t num);
void br_range_enc16be(void *dst, const uint16_t *v, size_t num);
void br_range_dec32le(uint32_t *v, size_t num, const void *src);
void br_range_dec32be(uint32_t *v, size_t num, const void *src);
void br_range_enc32le(void *dst, const uint32_t *v, size_t num);
void br_range_enc32be(void *dst, const uint32_t *v, size_t num);
void br_range_dec64le(uint64_t *v, size_t num, const void *src);
void br_range_dec64be(uint64_t *v, size_t num, const void *src);
void br_range_enc64le(void *dst, const uint64_t *v, size_t num);
void br_range_enc64be(void *dst, const uint64_t *v, size_t num);
/*
* Byte-swap a 32-bit integer.
*/
static inline uint32_t
br_swap32(uint32_t x)
{
x = ((x & (uint32_t)0x00FF00FF) << 8)
| ((x >> 8) & (uint32_t)0x00FF00FF);
return (x << 16) | (x >> 16);
}
/* ==================================================================== */
/*
* Support code for hash functions.
*/
/*
* IV for MD5, SHA-1, SHA-224 and SHA-256.
*/
extern const uint32_t br_md5_IV[];
extern const uint32_t br_sha1_IV[];
extern const uint32_t br_sha224_IV[];
extern const uint32_t br_sha256_IV[];
/*
* Round functions for MD5, SHA-1, SHA-224 and SHA-256 (SHA-224 and
* SHA-256 use the same round function).
*/
void br_md5_round(const unsigned char *buf, uint32_t *val);
void br_sha1_round(const unsigned char *buf, uint32_t *val);
void br_sha2small_round(const unsigned char *buf, uint32_t *val);
/*
* The core function for the TLS PRF. It computes
* P_hash(secret, label + seed), and XORs the result into the dst buffer.
*/
void br_tls_phash(void *dst, size_t len,
const br_hash_class *dig,
const void *secret, size_t secret_len,
const char *label, const void *seed, size_t seed_len);
/*
* Copy all configured hash implementations from a multihash context
* to another.
*/
static inline void
br_multihash_copyimpl(br_multihash_context *dst,
const br_multihash_context *src)
{
memcpy((void *)dst->impl, src->impl, sizeof src->impl);
}
/* ==================================================================== */
/*
* Constant-time primitives. These functions manipulate 32-bit values in
* order to provide constant-time comparisons and multiplexers.
*
* Boolean values (the "ctl" bits) MUST have value 0 or 1.
*
* Implementation notes:
* =====================
*
* The uintN_t types are unsigned and with width exactly N bits; the C
* standard guarantees that computations are performed modulo 2^N, and
* there can be no overflow. Negation (unary '-') works on unsigned types
* as well.
*
* The intN_t types are guaranteed to have width exactly N bits, with no
* padding bit, and using two's complement representation. Casting
* intN_t to uintN_t really is conversion modulo 2^N. Beware that intN_t
* types, being signed, trigger implementation-defined behaviour on
* overflow (including raising some signal): with GCC, while modular
* arithmetics are usually applied, the optimizer may assume that
* overflows don't occur (unless the -fwrapv command-line option is
* added); Clang has the additional -ftrapv option to explicitly trap on
* integer overflow or underflow.
*/
/*
* Negate a boolean.
*/
static inline uint32_t
NOT(uint32_t ctl)
{
return ctl ^ 1;
}
/*
* Multiplexer: returns x if ctl == 1, y if ctl == 0.
*/
static inline uint32_t
MUX(uint32_t ctl, uint32_t x, uint32_t y)
{
return y ^ (-ctl & (x ^ y));
}
/*
* Equality check: returns 1 if x == y, 0 otherwise.
*/
static inline uint32_t
EQ(uint32_t x, uint32_t y)
{
uint32_t q;
q = x ^ y;
return NOT((q | -q) >> 31);
}
/*
* Inequality check: returns 1 if x != y, 0 otherwise.
*/
static inline uint32_t
NEQ(uint32_t x, uint32_t y)
{
uint32_t q;
q = x ^ y;
return (q | -q) >> 31;
}
/*
* Comparison: returns 1 if x > y, 0 otherwise.
*/
static inline uint32_t
GT(uint32_t x, uint32_t y)
{
/*
* If both x < 2^31 and x < 2^31, then y-x will have its high
* bit set if x > y, cleared otherwise.
*
* If either x >= 2^31 or y >= 2^31 (but not both), then the
* result is the high bit of x.
*
* If both x >= 2^31 and y >= 2^31, then we can virtually
* subtract 2^31 from both, and we are back to the first case.
* Since (y-2^31)-(x-2^31) = y-x, the subtraction is already
* fine.
*/
uint32_t z;
z = y - x;
return (z ^ ((x ^ y) & (x ^ z))) >> 31;
}
/*
* Other comparisons (greater-or-equal, lower-than, lower-or-equal).
*/
#define GE(x, y) NOT(GT(y, x))
#define LT(x, y) GT(y, x)
#define LE(x, y) NOT(GT(x, y))
/*
* General comparison: returned value is -1, 0 or 1, depending on
* whether x is lower than, equal to, or greater than y.
*/
static inline int32_t
CMP(uint32_t x, uint32_t y)
{
return (int32_t)GT(x, y) | -(int32_t)GT(y, x);
}
/*
* Returns 1 if x == 0, 0 otherwise. Take care that the operand is signed.
*/
static inline uint32_t
EQ0(int32_t x)
{
uint32_t q;
q = (uint32_t)x;
return ~(q | -q) >> 31;
}
/*
* Returns 1 if x > 0, 0 otherwise. Take care that the operand is signed.
*/
static inline uint32_t
GT0(int32_t x)
{
/*
* High bit of -x is 0 if x == 0, but 1 if x > 0.
*/
uint32_t q;
q = (uint32_t)x;
return (~q & -q) >> 31;
}
/*
* Returns 1 if x >= 0, 0 otherwise. Take care that the operand is signed.
*/
static inline uint32_t
GE0(int32_t x)
{
return ~(uint32_t)x >> 31;
}
/*
* Returns 1 if x < 0, 0 otherwise. Take care that the operand is signed.
*/
static inline uint32_t
LT0(int32_t x)
{
return (uint32_t)x >> 31;
}
/*
* Returns 1 if x <= 0, 0 otherwise. Take care that the operand is signed.
*/
static inline uint32_t
LE0(int32_t x)
{
uint32_t q;
/*
* ~-x has its high bit set if and only if -x is nonnegative (as
* a signed int), i.e. x is in the -(2^31-1) to 0 range. We must
* do an OR with x itself to account for x = -2^31.
*/
q = (uint32_t)x;
return (q | ~-q) >> 31;
}
/*
* Conditional copy: src[] is copied into dst[] if and only if ctl is 1.
* dst[] and src[] may overlap completely (but not partially).
*/
void br_ccopy(uint32_t ctl, void *dst, const void *src, size_t len);
#define CCOPY br_ccopy
/*
* Compute the bit length of a 32-bit integer. Returned value is between 0
* and 32 (inclusive).
*/
static inline uint32_t
BIT_LENGTH(uint32_t x)
{
uint32_t k, c;
k = NEQ(x, 0);
c = GT(x, 0xFFFF); x = MUX(c, x >> 16, x); k += c << 4;
c = GT(x, 0x00FF); x = MUX(c, x >> 8, x); k += c << 3;
c = GT(x, 0x000F); x = MUX(c, x >> 4, x); k += c << 2;
c = GT(x, 0x0003); x = MUX(c, x >> 2, x); k += c << 1;
k += GT(x, 0x0001);
return k;
}
/*
* Compute the minimum of x and y.
*/
static inline uint32_t
MIN(uint32_t x, uint32_t y)
{
return MUX(GT(x, y), y, x);
}
/*
* Compute the maximum of x and y.
*/
static inline uint32_t
MAX(uint32_t x, uint32_t y)
{
return MUX(GT(x, y), x, y);
}
/*
* Multiply two 32-bit integers, with a 64-bit result. This default
* implementation assumes that the basic multiplication operator
* yields constant-time code.
*/
#define MUL(x, y) ((uint64_t)(x) * (uint64_t)(y))
#if BR_CT_MUL31
/*
* Alternate implementation of MUL31, that will be constant-time on some
* (old) platforms where the default MUL31 is not. Unfortunately, it is
* also substantially slower, and yields larger code, on more modern
* platforms, which is why it is deactivated by default.
*
* MUL31_lo() must do some extra work because on some platforms, the
* _signed_ multiplication may return early if the top bits are 1.
* Simply truncating (casting) the output of MUL31() would not be
* sufficient, because the compiler may notice that we keep only the low
* word, and then replace automatically the unsigned multiplication with
* a signed multiplication opcode.
*/
#define MUL31(x, y) ((uint64_t)((x) | (uint32_t)0x80000000) \
* (uint64_t)((y) | (uint32_t)0x80000000) \
- ((uint64_t)(x) << 31) - ((uint64_t)(y) << 31) \
- ((uint64_t)1 << 62))
static inline uint32_t
MUL31_lo(uint32_t x, uint32_t y)
{
uint32_t xl, xh;
uint32_t yl, yh;
xl = (x & 0xFFFF) | (uint32_t)0x80000000;
xh = (x >> 16) | (uint32_t)0x80000000;
yl = (y & 0xFFFF) | (uint32_t)0x80000000;
yh = (y >> 16) | (uint32_t)0x80000000;
return (xl * yl + ((xl * yh + xh * yl) << 16)) & (uint32_t)0x7FFFFFFF;
}
#else
/*
* Multiply two 31-bit integers, with a 62-bit result. This default
* implementation assumes that the basic multiplication operator
* yields constant-time code.
* The MUL31_lo() macro returns only the low 31 bits of the product.
*/
#define MUL31(x, y) ((uint64_t)(x) * (uint64_t)(y))
#define MUL31_lo(x, y) (((uint32_t)(x) * (uint32_t)(y)) & (uint32_t)0x7FFFFFFF)
#endif
/*
* Multiply two words together; the sum of the lengths of the two
* operands must not exceed 31 (for instance, one operand may use 16
* bits if the other fits on 15). If BR_CT_MUL15 is non-zero, then the
* macro will contain some extra operations that help in making the
* operation constant-time on some platforms, where the basic 32-bit
* multiplication is not constant-time.
*/
#if BR_CT_MUL15
#define MUL15(x, y) (((uint32_t)(x) | (uint32_t)0x80000000) \
* ((uint32_t)(y) | (uint32_t)0x80000000) \
& (uint32_t)0x7FFFFFFF)
#else
#define MUL15(x, y) ((uint32_t)(x) * (uint32_t)(y))
#endif
/*
* Arithmetic right shift (sign bit is copied). What happens when
* right-shifting a negative value is _implementation-defined_, so it
* does not trigger undefined behaviour, but it is still up to each
* compiler to define (and document) what it does. Most/all compilers
* will do an arithmetic shift, the sign bit being used to fill the
* holes; this is a native operation on the underlying CPU, and it would
* make little sense for the compiler to do otherwise. GCC explicitly
* documents that it follows that convention.
*
* Still, if BR_NO_ARITH_SHIFT is defined (and non-zero), then an
* alternate version will be used, that does not rely on such
* implementation-defined behaviour. Unfortunately, it is also slower
* and yields bigger code, which is why it is deactivated by default.
*/
#if BR_NO_ARITH_SHIFT
#define ARSH(x, n) (((uint32_t)(x) >> (n)) \
| ((-((uint32_t)(x) >> 31)) << (32 - (n))))
#else
#define ARSH(x, n) ((*(int32_t *)&(x)) >> (n))
#endif
/*
* Constant-time division. The dividend hi:lo is divided by the
* divisor d; the quotient is returned and the remainder is written
* in *r. If hi == d, then the quotient does not fit on 32 bits;
* returned value is thus truncated. If hi > d, returned values are
* indeterminate.
*/
uint32_t br_divrem(uint32_t hi, uint32_t lo, uint32_t d, uint32_t *r);
/*
* Wrapper for br_divrem(); the remainder is returned, and the quotient
* is discarded.
*/
static inline uint32_t
br_rem(uint32_t hi, uint32_t lo, uint32_t d)
{
uint32_t r;
br_divrem(hi, lo, d, &r);
return r;
}
/*
* Wrapper for br_divrem(); the quotient is returned, and the remainder
* is discarded.
*/
static inline uint32_t
br_div(uint32_t hi, uint32_t lo, uint32_t d)
{
uint32_t r;
return br_divrem(hi, lo, d, &r);
}
/* ==================================================================== */
/*
* Integers 'i32'
* --------------
*
* The 'i32' functions implement computations on big integers using
* an internal representation as an array of 32-bit integers. For
* an array x[]:
* -- x[0] contains the "announced bit length" of the integer
* -- x[1], x[2]... contain the value in little-endian order (x[1]
* contains the least significant 32 bits)
*
* Multiplications rely on the elementary 32x32->64 multiplication.
*
* The announced bit length specifies the number of bits that are
* significant in the subsequent 32-bit words. Unused bits in the
* last (most significant) word are set to 0; subsequent words are
* uninitialized and need not exist at all.
*
* The execution time and memory access patterns of all computations
* depend on the announced bit length, but not on the actual word
* values. For modular integers, the announced bit length of any integer
* modulo n is equal to the actual bit length of n; thus, computations
* on modular integers are "constant-time" (only the modulus length may
* leak).
*/
/*
* Compute the actual bit length of an integer. The argument x should
* point to the first (least significant) value word of the integer.
* The len 'xlen' contains the number of 32-bit words to access.
*
* CT: value or length of x does not leak.
*/
uint32_t br_i32_bit_length(uint32_t *x, size_t xlen);
/*
* Decode an integer from its big-endian unsigned representation. The
* "true" bit length of the integer is computed, but all words of x[]
* corresponding to the full 'len' bytes of the source are set.
*
* CT: value or length of x does not leak.
*/
void br_i32_decode(uint32_t *x, const void *src, size_t len);
/*
* Decode an integer from its big-endian unsigned representation. The
* integer MUST be lower than m[]; the announced bit length written in
* x[] will be equal to that of m[]. All 'len' bytes from the source are
* read.
*
* Returned value is 1 if the decode value fits within the modulus, 0
* otherwise. In the latter case, the x[] buffer will be set to 0 (but
* still with the announced bit length of m[]).
*
* CT: value or length of x does not leak. Memory access pattern depends
* only of 'len' and the announced bit length of m. Whether x fits or
* not does not leak either.
*/
uint32_t br_i32_decode_mod(uint32_t *x,
const void *src, size_t len, const uint32_t *m);
/*
* Reduce an integer (a[]) modulo another (m[]). The result is written
* in x[] and its announced bit length is set to be equal to that of m[].
*
* x[] MUST be distinct from a[] and m[].
*
* CT: only announced bit lengths leak, not values of x, a or m.
*/
void br_i32_reduce(uint32_t *x, const uint32_t *a, const uint32_t *m);
/*
* Decode an integer from its big-endian unsigned representation, and
* reduce it modulo the provided modulus m[]. The announced bit length
* of the result is set to be equal to that of the modulus.
*
* x[] MUST be distinct from m[].
*/
void br_i32_decode_reduce(uint32_t *x,
const void *src, size_t len, const uint32_t *m);
/*
* Encode an integer into its big-endian unsigned representation. The
* output length in bytes is provided (parameter 'len'); if the length
* is too short then the integer is appropriately truncated; if it is
* too long then the extra bytes are set to 0.
*/
void br_i32_encode(void *dst, size_t len, const uint32_t *x);
/*
* Multiply x[] by 2^32 and then add integer z, modulo m[]. This
* function assumes that x[] and m[] have the same announced bit
* length, and the announced bit length of m[] matches its true
* bit length.
*
* x[] and m[] MUST be distinct arrays.
*
* CT: only the common announced bit length of x and m leaks, not
* the values of x, z or m.
*/
void br_i32_muladd_small(uint32_t *x, uint32_t z, const uint32_t *m);
/*
* Extract one word from an integer. The offset is counted in bits.
* The word MUST entirely fit within the word elements corresponding
* to the announced bit length of a[].
*/
static inline uint32_t
br_i32_word(const uint32_t *a, uint32_t off)
{
size_t u;
unsigned j;
u = (size_t)(off >> 5) + 1;
j = (unsigned)off & 31;
if (j == 0) {
return a[u];
} else {
return (a[u] >> j) | (a[u + 1] << (32 - j));
}
}
/*
* Test whether an integer is zero.
*/
uint32_t br_i32_iszero(const uint32_t *x);
/*
* Add b[] to a[] and return the carry (0 or 1). If ctl is 0, then a[]
* is unmodified, but the carry is still computed and returned. The
* arrays a[] and b[] MUST have the same announced bit length.
*
* a[] and b[] MAY be the same array, but partial overlap is not allowed.
*/
uint32_t br_i32_add(uint32_t *a, const uint32_t *b, uint32_t ctl);
/*
* Subtract b[] from a[] and return the carry (0 or 1). If ctl is 0,
* then a[] is unmodified, but the carry is still computed and returned.
* The arrays a[] and b[] MUST have the same announced bit length.
*
* a[] and b[] MAY be the same array, but partial overlap is not allowed.
*/
uint32_t br_i32_sub(uint32_t *a, const uint32_t *b, uint32_t ctl);
/*
* Compute d+a*b, result in d. The initial announced bit length of d[]
* MUST match that of a[]. The d[] array MUST be large enough to
* accommodate the full result, plus (possibly) an extra word. The
* resulting announced bit length of d[] will be the sum of the announced
* bit lengths of a[] and b[] (therefore, it may be larger than the actual
* bit length of the numerical result).
*
* a[] and b[] may be the same array. d[] must be disjoint from both a[]
* and b[].
*/
void br_i32_mulacc(uint32_t *d, const uint32_t *a, const uint32_t *b);
/*
* Zeroize an integer. The announced bit length is set to the provided
* value, and the corresponding words are set to 0.
*/
static inline void
br_i32_zero(uint32_t *x, uint32_t bit_len)
{
*x ++ = bit_len;
memset(x, 0, ((bit_len + 31) >> 5) * sizeof *x);
}
/*
* Compute -(1/x) mod 2^32. If x is even, then this function returns 0.
*/
uint32_t br_i32_ninv32(uint32_t x);
/*
* Convert a modular integer to Montgomery representation. The integer x[]
* MUST be lower than m[], but with the same announced bit length.
*/
void br_i32_to_monty(uint32_t *x, const uint32_t *m);
/*
* Convert a modular integer back from Montgomery representation. The
* integer x[] MUST be lower than m[], but with the same announced bit
* length. The "m0i" parameter is equal to -(1/m0) mod 2^32, where m0 is
* the least significant value word of m[] (this works only if m[] is
* an odd integer).
*/
void br_i32_from_monty(uint32_t *x, const uint32_t *m, uint32_t m0i);
/*
* Compute a modular Montgomery multiplication. d[] is filled with the
* value of x*y/R modulo m[] (where R is the Montgomery factor). The
* array d[] MUST be distinct from x[], y[] and m[]. x[] and y[] MUST be
* numerically lower than m[]. x[] and y[] MAY be the same array. The
* "m0i" parameter is equal to -(1/m0) mod 2^32, where m0 is the least
* significant value word of m[] (this works only if m[] is an odd
* integer).
*/
void br_i32_montymul(uint32_t *d, const uint32_t *x, const uint32_t *y,
const uint32_t *m, uint32_t m0i);
/*
* Compute a modular exponentiation. x[] MUST be an integer modulo m[]
* (same announced bit length, lower value). m[] MUST be odd. The
* exponent is in big-endian unsigned notation, over 'elen' bytes. The
* "m0i" parameter is equal to -(1/m0) mod 2^32, where m0 is the least
* significant value word of m[] (this works only if m[] is an odd
* integer). The t1[] and t2[] parameters must be temporary arrays,
* each large enough to accommodate an integer with the same size as m[].
*/
void br_i32_modpow(uint32_t *x, const unsigned char *e, size_t elen,
const uint32_t *m, uint32_t m0i, uint32_t *t1, uint32_t *t2);
/* ==================================================================== */
/*
* Integers 'i31'
* --------------
*
* The 'i31' functions implement computations on big integers using
* an internal representation as an array of 32-bit integers. For
* an array x[]:
* -- x[0] encodes the array length and the "announced bit length"
* of the integer: namely, if the announced bit length is k,
* then x[0] = ((k / 31) << 5) + (k % 31).
* -- x[1], x[2]... contain the value in little-endian order, 31
* bits per word (x[1] contains the least significant 31 bits).
* The upper bit of each word is 0.
*
* Multiplications rely on the elementary 32x32->64 multiplication.
*
* The announced bit length specifies the number of bits that are
* significant in the subsequent 32-bit words. Unused bits in the
* last (most significant) word are set to 0; subsequent words are
* uninitialized and need not exist at all.
*
* The execution time and memory access patterns of all computations
* depend on the announced bit length, but not on the actual word
* values. For modular integers, the announced bit length of any integer
* modulo n is equal to the actual bit length of n; thus, computations
* on modular integers are "constant-time" (only the modulus length may
* leak).
*/
/*
* Test whether an integer is zero.
*/
uint32_t br_i31_iszero(const uint32_t *x);
/*
* Add b[] to a[] and return the carry (0 or 1). If ctl is 0, then a[]
* is unmodified, but the carry is still computed and returned. The
* arrays a[] and b[] MUST have the same announced bit length.
*
* a[] and b[] MAY be the same array, but partial overlap is not allowed.
*/
uint32_t br_i31_add(uint32_t *a, const uint32_t *b, uint32_t ctl);
/*
* Subtract b[] from a[] and return the carry (0 or 1). If ctl is 0,
* then a[] is unmodified, but the carry is still computed and returned.
* The arrays a[] and b[] MUST have the same announced bit length.
*
* a[] and b[] MAY be the same array, but partial overlap is not allowed.
*/
uint32_t br_i31_sub(uint32_t *a, const uint32_t *b, uint32_t ctl);
/*
* Compute the ENCODED actual bit length of an integer. The argument x
* should point to the first (least significant) value word of the
* integer. The len 'xlen' contains the number of 32-bit words to
* access. The upper bit of each value word MUST be 0.
* Returned value is ((k / 31) << 5) + (k % 31) if the bit length is k.
*
* CT: value or length of x does not leak.
*/
uint32_t br_i31_bit_length(uint32_t *x, size_t xlen);
/*
* Decode an integer from its big-endian unsigned representation. The
* "true" bit length of the integer is computed and set in the encoded
* announced bit length (x[0]), but all words of x[] corresponding to
* the full 'len' bytes of the source are set.
*
* CT: value or length of x does not leak.
*/
void br_i31_decode(uint32_t *x, const void *src, size_t len);
/*
* Decode an integer from its big-endian unsigned representation. The
* integer MUST be lower than m[]; the (encoded) announced bit length
* written in x[] will be equal to that of m[]. All 'len' bytes from the
* source are read.
*
* Returned value is 1 if the decode value fits within the modulus, 0
* otherwise. In the latter case, the x[] buffer will be set to 0 (but
* still with the announced bit length of m[]).
*
* CT: value or length of x does not leak. Memory access pattern depends
* only of 'len' and the announced bit length of m. Whether x fits or
* not does not leak either.
*/
uint32_t br_i31_decode_mod(uint32_t *x,
const void *src, size_t len, const uint32_t *m);
/*
* Zeroize an integer. The announced bit length is set to the provided
* value, and the corresponding words are set to 0. The ENCODED bit length
* is expected here.
*/
static inline void
br_i31_zero(uint32_t *x, uint32_t bit_len)
{
*x ++ = bit_len;
memset(x, 0, ((bit_len + 31) >> 5) * sizeof *x);
}
/*
* Right-shift an integer. The shift amount must be lower than 31
* bits.
*/
void br_i31_rshift(uint32_t *x, int count);
/*
* Reduce an integer (a[]) modulo another (m[]). The result is written
* in x[] and its announced bit length is set to be equal to that of m[].
*
* x[] MUST be distinct from a[] and m[].
*
* CT: only announced bit lengths leak, not values of x, a or m.
*/
void br_i31_reduce(uint32_t *x, const uint32_t *a, const uint32_t *m);
/*
* Decode an integer from its big-endian unsigned representation, and
* reduce it modulo the provided modulus m[]. The announced bit length
* of the result is set to be equal to that of the modulus.
*
* x[] MUST be distinct from m[].
*/
void br_i31_decode_reduce(uint32_t *x,
const void *src, size_t len, const uint32_t *m);
/*
* Multiply x[] by 2^31 and then add integer z, modulo m[]. This
* function assumes that x[] and m[] have the same announced bit
* length, the announced bit length of m[] matches its true
* bit length.
*
* x[] and m[] MUST be distinct arrays. z MUST fit in 31 bits (upper
* bit set to 0).
*
* CT: only the common announced bit length of x and m leaks, not
* the values of x, z or m.
*/
void br_i31_muladd_small(uint32_t *x, uint32_t z, const uint32_t *m);
/*
* Encode an integer into its big-endian unsigned representation. The
* output length in bytes is provided (parameter 'len'); if the length
* is too short then the integer is appropriately truncated; if it is
* too long then the extra bytes are set to 0.
*/
void br_i31_encode(void *dst, size_t len, const uint32_t *x);
/*
* Compute -(1/x) mod 2^31. If x is even, then this function returns 0.
*/
uint32_t br_i31_ninv31(uint32_t x);
/*
* Compute a modular Montgomery multiplication. d[] is filled with the
* value of x*y/R modulo m[] (where R is the Montgomery factor). The
* array d[] MUST be distinct from x[], y[] and m[]. x[] and y[] MUST be
* numerically lower than m[]. x[] and y[] MAY be the same array. The
* "m0i" parameter is equal to -(1/m0) mod 2^31, where m0 is the least
* significant value word of m[] (this works only if m[] is an odd
* integer).
*/
void br_i31_montymul(uint32_t *d, const uint32_t *x, const uint32_t *y,
const uint32_t *m, uint32_t m0i);
/*
* Convert a modular integer to Montgomery representation. The integer x[]
* MUST be lower than m[], but with the same announced bit length.
*/
void br_i31_to_monty(uint32_t *x, const uint32_t *m);
/*
* Convert a modular integer back from Montgomery representation. The
* integer x[] MUST be lower than m[], but with the same announced bit
* length. The "m0i" parameter is equal to -(1/m0) mod 2^32, where m0 is
* the least significant value word of m[] (this works only if m[] is
* an odd integer).
*/
void br_i31_from_monty(uint32_t *x, const uint32_t *m, uint32_t m0i);
/*
* Compute a modular exponentiation. x[] MUST be an integer modulo m[]
* (same announced bit length, lower value). m[] MUST be odd. The
* exponent is in big-endian unsigned notation, over 'elen' bytes. The
* "m0i" parameter is equal to -(1/m0) mod 2^31, where m0 is the least
* significant value word of m[] (this works only if m[] is an odd
* integer). The t1[] and t2[] parameters must be temporary arrays,
* each large enough to accommodate an integer with the same size as m[].
*/
void br_i31_modpow(uint32_t *x, const unsigned char *e, size_t elen,
const uint32_t *m, uint32_t m0i, uint32_t *t1, uint32_t *t2);
/*
* Compute d+a*b, result in d. The initial announced bit length of d[]
* MUST match that of a[]. The d[] array MUST be large enough to
* accommodate the full result, plus (possibly) an extra word. The
* resulting announced bit length of d[] will be the sum of the announced
* bit lengths of a[] and b[] (therefore, it may be larger than the actual
* bit length of the numerical result).
*
* a[] and b[] may be the same array. d[] must be disjoint from both a[]
* and b[].
*/
void br_i31_mulacc(uint32_t *d, const uint32_t *a, const uint32_t *b);
/* ==================================================================== */
static inline void
br_i15_zero(uint16_t *x, uint16_t bit_len)
{
*x ++ = bit_len;
memset(x, 0, ((bit_len + 15) >> 4) * sizeof *x);
}
uint32_t br_i15_iszero(const uint16_t *x);
uint16_t br_i15_ninv15(uint16_t x);
uint32_t br_i15_add(uint16_t *a, const uint16_t *b, uint32_t ctl);
uint32_t br_i15_sub(uint16_t *a, const uint16_t *b, uint32_t ctl);
void br_i15_muladd_small(uint16_t *x, uint16_t z, const uint16_t *m);
void br_i15_montymul(uint16_t *d, const uint16_t *x, const uint16_t *y,
const uint16_t *m, uint16_t m0i);
void br_i15_to_monty(uint16_t *x, const uint16_t *m);
void br_i15_modpow(uint16_t *x, const unsigned char *e, size_t elen,
const uint16_t *m, uint16_t m0i, uint16_t *t1, uint16_t *t2);
uint32_t br_i15_modpow_opt(uint16_t *x, const unsigned char *e, size_t elen,
const uint16_t *m, uint16_t m0i, uint16_t *tmp, size_t twlen);
void br_i15_encode(void *dst, size_t len, const uint16_t *x);
uint32_t br_i15_decode_mod(uint16_t *x,
const void *src, size_t len, const uint16_t *m);
void br_i15_rshift(uint16_t *x, int count);
uint32_t br_i15_bit_length(uint16_t *x, size_t xlen);
void br_i15_decode(uint16_t *x, const void *src, size_t len);
void br_i15_from_monty(uint16_t *x, const uint16_t *m, uint16_t m0i);
void br_i15_decode_reduce(uint16_t *x,
const void *src, size_t len, const uint16_t *m);
void br_i15_reduce(uint16_t *x, const uint16_t *a, const uint16_t *m);
void br_i15_mulacc(uint16_t *d, const uint16_t *a, const uint16_t *b);
/* ==================================================================== */
static inline size_t
br_digest_size(const br_hash_class *digest_class)
{
return (size_t)(digest_class->desc >> BR_HASHDESC_OUT_OFF)
& BR_HASHDESC_OUT_MASK;
}
/*
* Get the output size (in bytes) of a hash function.
*/
size_t br_digest_size_by_ID(int digest_id);
/*
* Get the OID (encoded OBJECT IDENTIFIER value, without tag and length)
* for a hash function. If digest_id is not a supported digest identifier
* (in particular if it is equal to 0, i.e. br_md5sha1_ID), then NULL is
* returned and *len is set to 0.
*/
const unsigned char *br_digest_OID(int digest_id, size_t *len);
/* ==================================================================== */
/*
* DES support functions.
*/
/*
* Apply DES Initial Permutation.
*/
void br_des_do_IP(uint32_t *xl, uint32_t *xr);
/*
* Apply DES Final Permutation (inverse of IP).
*/
void br_des_do_invIP(uint32_t *xl, uint32_t *xr);
/*
* Key schedule unit: for a DES key (8 bytes), compute 16 subkeys. Each
* subkey is two 28-bit words represented as two 32-bit words; the PC-2
* bit extration is NOT applied.
*/
void br_des_keysched_unit(uint32_t *skey, const void *key);
/*
* Reversal of 16 DES sub-keys (for decryption).
*/
void br_des_rev_skey(uint32_t *skey);
/*
* DES/3DES key schedule for 'des_tab' (encryption direction). Returned
* value is the number of rounds.
*/
unsigned br_des_tab_keysched(uint32_t *skey, const void *key, size_t key_len);
/*
* DES/3DES key schedule for 'des_ct' (encryption direction). Returned
* value is the number of rounds.
*/
unsigned br_des_ct_keysched(uint32_t *skey, const void *key, size_t key_len);
/*
* DES/3DES subkey decompression (from the compressed bitsliced subkeys).
*/
void br_des_ct_skey_expand(uint32_t *sk_exp,
unsigned num_rounds, const uint32_t *skey);
/*
* DES/3DES block encryption/decryption ('des_tab').
*/
void br_des_tab_process_block(unsigned num_rounds,
const uint32_t *skey, void *block);
/*
* DES/3DES block encryption/decryption ('des_ct').
*/
void br_des_ct_process_block(unsigned num_rounds,
const uint32_t *skey, void *block);
/* ==================================================================== */
/*
* AES support functions.
*/
/*
* The AES S-box (256-byte table).
*/
extern const unsigned char br_aes_S[];
/*
* AES key schedule. skey[] is filled with n+1 128-bit subkeys, where n
* is the number of rounds (10 to 14, depending on key size). The number
* of rounds is returned. If the key size is invalid (not 16, 24 or 32),
* then 0 is returned.
*
* This implementation uses a 256-byte table and is NOT constant-time.
*/
unsigned br_aes_keysched(uint32_t *skey, const void *key, size_t key_len);
/*
* AES key schedule for decryption ('aes_big' implementation).
*/
unsigned br_aes_big_keysched_inv(uint32_t *skey,
const void *key, size_t key_len);
/*
* AES block encryption with the 'aes_big' implementation (fast, but
* not constant-time). This function encrypts a single block "in place".
*/
void br_aes_big_encrypt(unsigned num_rounds, const uint32_t *skey, void *data);
/*
* AES block decryption with the 'aes_big' implementation (fast, but
* not constant-time). This function decrypts a single block "in place".
*/
void br_aes_big_decrypt(unsigned num_rounds, const uint32_t *skey, void *data);
/*
* AES block encryption with the 'aes_small' implementation (small, but
* slow and not constant-time). This function encrypts a single block
* "in place".
*/
void br_aes_small_encrypt(unsigned num_rounds,
const uint32_t *skey, void *data);
/*
* AES block decryption with the 'aes_small' implementation (small, but
* slow and not constant-time). This function decrypts a single block
* "in place".
*/
void br_aes_small_decrypt(unsigned num_rounds,
const uint32_t *skey, void *data);
/*
* The constant-time implementation is "bitsliced": the 128-bit state is
* split over eight 32-bit words q* in the following way:
*
* -- Input block consists in 16 bytes:
* a00 a10 a20 a30 a01 a11 a21 a31 a02 a12 a22 a32 a03 a13 a23 a33
* In the terminology of FIPS 197, this is a 4x4 matrix which is read
* column by column.
*
* -- Each byte is split into eight bits which are distributed over the
* eight words, at the same rank. Thus, for a byte x at rank k, bit 0
* (least significant) of x will be at rank k in q0 (if that bit is b,
* then it contributes "b << k" to the value of q0), bit 1 of x will be
* at rank k in q1, and so on.
*
* -- Ranks given to bits are in "row order" and are either all even, or
* all odd. Two independent AES states are thus interleaved, one using
* the even ranks, the other the odd ranks. Row order means:
* a00 a01 a02 a03 a10 a11 a12 a13 a20 a21 a22 a23 a30 a31 a32 a33
*
* Converting input bytes from two AES blocks to bitslice representation
* is done in the following way:
* -- Decode first block into the four words q0 q2 q4 q6, in that order,
* using little-endian convention.
* -- Decode second block into the four words q1 q3 q5 q7, in that order,
* using little-endian convention.
* -- Call br_aes_ct_ortho().
*
* Converting back to bytes is done by using the reverse operations. Note
* that br_aes_ct_ortho() is its own inverse.
*/
/*
* Perform bytewise orthogonalization of eight 32-bit words. Bytes
* of q0..q7 are spread over all words: for a byte x that occurs
* at rank i in q[j] (byte x uses bits 8*i to 8*i+7 in q[j]), the bit
* of rank k in x (0 <= k <= 7) goes to q[k] at rank 8*i+j.
*
* This operation is an involution.
*/
void br_aes_ct_ortho(uint32_t *q);
/*
* The AES S-box, as a bitsliced constant-time version. The input array
* consists in eight 32-bit words; 32 S-box instances are computed in
* parallel. Bits 0 to 7 of each S-box input (bit 0 is least significant)
* are spread over the words 0 to 7, at the same rank.
*/
void br_aes_ct_bitslice_Sbox(uint32_t *q);
/*
* Like br_aes_bitslice_Sbox(), but for the inverse S-box.
*/
void br_aes_ct_bitslice_invSbox(uint32_t *q);
/*
* Compute AES encryption on bitsliced data. Since input is stored on
* eight 32-bit words, two block encryptions are actually performed
* in parallel.
*/
void br_aes_ct_bitslice_encrypt(unsigned num_rounds,
const uint32_t *skey, uint32_t *q);
/*
* Compute AES decryption on bitsliced data. Since input is stored on
* eight 32-bit words, two block decryptions are actually performed
* in parallel.
*/
void br_aes_ct_bitslice_decrypt(unsigned num_rounds,
const uint32_t *skey, uint32_t *q);
/*
* AES key schedule, constant-time version. skey[] is filled with n+1
* 128-bit subkeys, where n is the number of rounds (10 to 14, depending
* on key size). The number of rounds is returned. If the key size is
* invalid (not 16, 24 or 32), then 0 is returned.
*/
unsigned br_aes_ct_keysched(uint32_t *comp_skey,
const void *key, size_t key_len);
/*
* Expand AES subkeys as produced by br_aes_ct_keysched(), into
* a larger array suitable for br_aes_ct_bitslice_encrypt() and
* br_aes_ct_bitslice_decrypt().
*/
void br_aes_ct_skey_expand(uint32_t *skey,
unsigned num_rounds, const uint32_t *comp_skey);
/*
* For the ct64 implementation, the same bitslicing technique is used,
* but four instances are interleaved. First instance uses bits 0, 4,
* 8, 12,... of each word; second instance uses bits 1, 5, 9, 13,...
* and so on.
*/
/*
* Perform bytewise orthogonalization of eight 64-bit words. Bytes
* of q0..q7 are spread over all words: for a byte x that occurs
* at rank i in q[j] (byte x uses bits 8*i to 8*i+7 in q[j]), the bit
* of rank k in x (0 <= k <= 7) goes to q[k] at rank 8*i+j.
*
* This operation is an involution.
*/
void br_aes_ct64_ortho(uint64_t *q);
/*
* Interleave bytes for an AES input block. If input bytes are
* denoted 0123456789ABCDEF, and have been decoded with little-endian
* convention (w[0] contains 0123, with '3' being most significant;
* w[1] contains 4567, and so on), then output word q0 will be
* set to 08192A3B (again little-endian convention) and q1 will
* be set to 4C5D6E7F.
*/
void br_aes_ct64_interleave_in(uint64_t *q0, uint64_t *q1, const uint32_t *w);
/*
* Perform the opposite of br_aes_ct64_interleave_in().
*/
void br_aes_ct64_interleave_out(uint32_t *w, uint64_t q0, uint64_t q1);
/*
* The AES S-box, as a bitsliced constant-time version. The input array
* consists in eight 64-bit words; 64 S-box instances are computed in
* parallel. Bits 0 to 7 of each S-box input (bit 0 is least significant)
* are spread over the words 0 to 7, at the same rank.
*/
void br_aes_ct64_bitslice_Sbox(uint64_t *q);
/*
* Like br_aes_bitslice_Sbox(), but for the inverse S-box.
*/
void br_aes_ct64_bitslice_invSbox(uint64_t *q);
/*
* Compute AES encryption on bitsliced data. Since input is stored on
* eight 64-bit words, four block encryptions are actually performed
* in parallel.
*/
void br_aes_ct64_bitslice_encrypt(unsigned num_rounds,
const uint64_t *skey, uint64_t *q);
/*
* Compute AES decryption on bitsliced data. Since input is stored on
* eight 64-bit words, four block decryptions are actually performed
* in parallel.
*/
void br_aes_ct64_bitslice_decrypt(unsigned num_rounds,
const uint64_t *skey, uint64_t *q);
/*
* AES key schedule, constant-time version. skey[] is filled with n+1
* 128-bit subkeys, where n is the number of rounds (10 to 14, depending
* on key size). The number of rounds is returned. If the key size is
* invalid (not 16, 24 or 32), then 0 is returned.
*/
unsigned br_aes_ct64_keysched(uint64_t *comp_skey,
const void *key, size_t key_len);
/*
* Expand AES subkeys as produced by br_aes_ct64_keysched(), into
* a larger array suitable for br_aes_ct64_bitslice_encrypt() and
* br_aes_ct64_bitslice_decrypt().
*/
void br_aes_ct64_skey_expand(uint64_t *skey,
unsigned num_rounds, const uint64_t *comp_skey);
/* ==================================================================== */
/*
* RSA.
*/
/*
* Apply proper PKCS#1 v1.5 padding (for signatures). 'hash_oid' is
* the encoded hash function OID, or NULL.
*/
uint32_t br_rsa_pkcs1_sig_pad(const unsigned char *hash_oid,
const unsigned char *hash, size_t hash_len,
uint32_t n_bitlen, unsigned char *x);
/*
* Check PKCS#1 v1.5 padding (for signatures). 'hash_oid' is the encoded
* hash function OID, or NULL. The provided 'sig' value is _after_ the
* modular exponentiation, i.e. it should be the padded hash. On
* success, the hashed message is extracted.
*/
uint32_t br_rsa_pkcs1_sig_unpad(const unsigned char *sig, size_t sig_len,
const unsigned char *hash_oid, size_t hash_len,
unsigned char *hash_out);
/* ==================================================================== */
/*
* Elliptic curves.
*/
/*
* Type for generic EC parameters: curve order (unsigned big-endian
* encoding) and encoded conventional generator.
*/
typedef struct {
int curve;
const unsigned char *order;
size_t order_len;
const unsigned char *generator;
size_t generator_len;
} br_ec_curve_def;
extern const br_ec_curve_def br_secp256r1;
extern const br_ec_curve_def br_secp384r1;
extern const br_ec_curve_def br_secp521r1;
/*
* For Curve25519, the advertised "order" really is 2^255-1, since the
* point multipliction function really works over arbitrary 255-bit
* scalars. This value is only meant as a hint for ECDH key generation;
* only ECDSA uses the exact curve order, and ECDSA is not used with
* that specific curve.
*/
extern const br_ec_curve_def br_curve25519;
/*
* Decode some bytes as an i31 integer, with truncation (corresponding
* to the 'bits2int' operation in RFC 6979). The target ENCODED bit
* length is provided as last parameter. The resulting value will have
* this declared bit length, and consists the big-endian unsigned decoding
* of exactly that many bits in the source (capped at the source length).
*/
void br_ecdsa_i31_bits2int(uint32_t *x,
const void *src, size_t len, uint32_t ebitlen);
/*
* Decode some bytes as an i15 integer, with truncation (corresponding
* to the 'bits2int' operation in RFC 6979). The target ENCODED bit
* length is provided as last parameter. The resulting value will have
* this declared bit length, and consists the big-endian unsigned decoding
* of exactly that many bits in the source (capped at the source length).
*/
void br_ecdsa_i15_bits2int(uint16_t *x,
const void *src, size_t len, uint32_t ebitlen);
/* ==================================================================== */
/*
* SSL/TLS support functions.
*/
/*
* Record types.
*/
#define BR_SSL_CHANGE_CIPHER_SPEC 20
#define BR_SSL_ALERT 21
#define BR_SSL_HANDSHAKE 22
#define BR_SSL_APPLICATION_DATA 23
/*
* Handshake message types.
*/
#define BR_SSL_HELLO_REQUEST 0
#define BR_SSL_CLIENT_HELLO 1
#define BR_SSL_SERVER_HELLO 2
#define BR_SSL_CERTIFICATE 11
#define BR_SSL_SERVER_KEY_EXCHANGE 12
#define BR_SSL_CERTIFICATE_REQUEST 13
#define BR_SSL_SERVER_HELLO_DONE 14
#define BR_SSL_CERTIFICATE_VERIFY 15
#define BR_SSL_CLIENT_KEY_EXCHANGE 16
#define BR_SSL_FINISHED 20
/*
* Alert levels.
*/
#define BR_LEVEL_WARNING 1
#define BR_LEVEL_FATAL 2
/*
* Low-level I/O state.
*/
#define BR_IO_FAILED 0
#define BR_IO_IN 1
#define BR_IO_OUT 2
#define BR_IO_INOUT 3
/*
* Mark a SSL engine as failed. The provided error code is recorded if
* the engine was not already marked as failed. If 'err' is 0, then the
* engine is marked as closed (without error).
*/
void br_ssl_engine_fail(br_ssl_engine_context *cc, int err);
/*
* Test whether the engine is closed (normally or as a failure).
*/
static inline int
br_ssl_engine_closed(const br_ssl_engine_context *cc)
{
return cc->iomode == BR_IO_FAILED;
}
/*
* Configure a new maximum fragment length. If possible, the maximum
* length for outgoing records is immediately adjusted (if there are
* not already too many buffered bytes for that).
*/
void br_ssl_engine_new_max_frag_len(
br_ssl_engine_context *rc, unsigned max_frag_len);
/*
* Test whether the current incoming record has been fully received
* or not. This functions returns 0 only if a complete record header
* has been received, but some of the (possibly encrypted) payload
* has not yet been obtained.
*/
int br_ssl_engine_recvrec_finished(const br_ssl_engine_context *rc);
/*
* Flush the current record (if not empty). This is meant to be called
* from the handshake processor only.
*/
void br_ssl_engine_flush_record(br_ssl_engine_context *cc);
/*
* Test whether there is some accumulated payload to send.
*/
static inline int
br_ssl_engine_has_pld_to_send(const br_ssl_engine_context *rc)
{
return rc->oxa != rc->oxb && rc->oxa != rc->oxc;
}
/*
* Initialize RNG in engine. Returned value is 1 on success, 0 on error.
* This function will try to use the OS-provided RNG, if available. If
* there is no OS-provided RNG, or if it failed, and no entropy was
* injected by the caller, then a failure will be reported. On error,
* the context error code is set.
*/
int br_ssl_engine_init_rand(br_ssl_engine_context *cc);
/*
* Reset the handshake-related parts of the engine.
*/
void br_ssl_engine_hs_reset(br_ssl_engine_context *cc,
void (*hsinit)(void *), void (*hsrun)(void *));
/*
* Get the PRF to use for this context, for the provided PRF hash
* function ID.
*/
br_tls_prf_impl br_ssl_engine_get_PRF(br_ssl_engine_context *cc, int prf_id);
/*
* Consume the provided pre-master secret and compute the corresponding
* master secret. The 'prf_id' is the ID of the hash function to use
* with the TLS 1.2 PRF (ignored if the version is TLS 1.0 or 1.1).
*/
void br_ssl_engine_compute_master(br_ssl_engine_context *cc,
int prf_id, const void *pms, size_t len);
/*
* Switch to CBC decryption for incoming records.
* cc the engine context
* is_client non-zero for a client, zero for a server
* prf_id id of hash function for PRF (ignored if not TLS 1.2+)
* mac_id id of hash function for HMAC
* bc_impl block cipher implementation (CBC decryption)
* cipher_key_len block cipher key length (in bytes)
*/
void br_ssl_engine_switch_cbc_in(br_ssl_engine_context *cc,
int is_client, int prf_id, int mac_id,
const br_block_cbcdec_class *bc_impl, size_t cipher_key_len);
/*
* Switch to CBC encryption for outgoing records.
* cc the engine context
* is_client non-zero for a client, zero for a server
* prf_id id of hash function for PRF (ignored if not TLS 1.2+)
* mac_id id of hash function for HMAC
* bc_impl block cipher implementation (CBC encryption)
* cipher_key_len block cipher key length (in bytes)
*/
void br_ssl_engine_switch_cbc_out(br_ssl_engine_context *cc,
int is_client, int prf_id, int mac_id,
const br_block_cbcenc_class *bc_impl, size_t cipher_key_len);
/*
* Switch to GCM decryption for incoming records.
* cc the engine context
* is_client non-zero for a client, zero for a server
* prf_id id of hash function for PRF
* bc_impl block cipher implementation (CTR)
* cipher_key_len block cipher key length (in bytes)
*/
void br_ssl_engine_switch_gcm_in(br_ssl_engine_context *cc,
int is_client, int prf_id,
const br_block_ctr_class *bc_impl, size_t cipher_key_len);
/*
* Switch to GCM encryption for outgoing records.
* cc the engine context
* is_client non-zero for a client, zero for a server
* prf_id id of hash function for PRF
* bc_impl block cipher implementation (CTR)
* cipher_key_len block cipher key length (in bytes)
*/
void br_ssl_engine_switch_gcm_out(br_ssl_engine_context *cc,
int is_client, int prf_id,
const br_block_ctr_class *bc_impl, size_t cipher_key_len);
/*
* Switch to ChaCha20+Poly1305 decryption for incoming records.
* cc the engine context
* is_client non-zero for a client, zero for a server
* prf_id id of hash function for PRF
*/
void br_ssl_engine_switch_chapol_in(br_ssl_engine_context *cc,
int is_client, int prf_id);
/*
* Switch to ChaCha20+Poly1305 encryption for outgoing records.
* cc the engine context
* is_client non-zero for a client, zero for a server
* prf_id id of hash function for PRF
*/
void br_ssl_engine_switch_chapol_out(br_ssl_engine_context *cc,
int is_client, int prf_id);
/*
* Calls to T0-generated code.
*/
void br_ssl_hs_client_init_main(void *ctx);
void br_ssl_hs_client_run(void *ctx);
void br_ssl_hs_server_init_main(void *ctx);
void br_ssl_hs_server_run(void *ctx);
/*
* Get the hash function to use for signatures, given a bit mask of
* supported hash functions. This implements a strict choice order
* (namely SHA-256, SHA-384, SHA-512, SHA-224, SHA-1). If the mask
* does not document support of any of these hash functions, then this
* functions returns 0.
*/
int br_ssl_choose_hash(unsigned bf);
/* ==================================================================== */
#endif