mirror of
https://github.com/michaelrsweet/pdfio.git
synced 2024-11-19 11:58:24 +01:00
481 lines
16 KiB
C
481 lines
16 KiB
C
//
|
||
// SHA-256 functions for PDFio.
|
||
//
|
||
// Copyright © 2021 by Michael R Sweet.
|
||
// Copyright © 2011 IETF Trust and the persons identified as authors of the
|
||
// code. All rights reserved.
|
||
//
|
||
// Redistribution and use in source and binary forms, with or
|
||
// without modification, are permitted provided that the following
|
||
// conditions are met:
|
||
//
|
||
// - Redistributions of source code must retain the above
|
||
// copyright notice, this list of conditions and
|
||
// the following disclaimer.
|
||
//
|
||
// - Redistributions in binary form must reproduce the above
|
||
// copyright notice, this list of conditions and the following
|
||
// disclaimer in the documentation and/or other materials provided
|
||
// with the distribution.
|
||
//
|
||
// - Neither the name of Internet Society, IETF or IETF Trust, nor
|
||
// the names of specific contributors, may be used to endorse or
|
||
// promote products derived from this software without specific
|
||
// prior written permission.
|
||
//
|
||
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
|
||
// CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
|
||
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
|
||
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
||
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
|
||
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
||
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
||
// NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
||
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
||
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
|
||
// OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
|
||
// EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||
//
|
||
|
||
/*
|
||
* Description:
|
||
* This file implements the Secure Hash Algorithms SHA-224 and
|
||
* SHA-256 as defined in the U.S. National Institute of Standards
|
||
* and Technology Federal Information Processing Standards
|
||
* Publication (FIPS PUB) 180-3 published in October 2008
|
||
* and formerly defined in its predecessors, FIPS PUB 180-1
|
||
* and FIP PUB 180-2.
|
||
*
|
||
* A combined document showing all algorithms is available at
|
||
* http://csrc.nist.gov/publications/fips/
|
||
* fips180-3/fips180-3_final.pdf
|
||
*
|
||
* The SHA-224 and SHA-256 algorithms produce 224-bit and 256-bit
|
||
* message digests for a given data stream. It should take about
|
||
* 2**n steps to find a message with the same digest as a given
|
||
* message and 2**(n/2) to find any two messages with the same
|
||
* digest, when n is the digest size in bits. Therefore, this
|
||
* algorithm can serve as a means of providing a
|
||
* "fingerprint" for a message.
|
||
*
|
||
* Portability Issues:
|
||
* SHA-224 and SHA-256 are defined in terms of 32-bit "words".
|
||
* This code uses <stdint.h> (included via "sha.h") to define 32-
|
||
* and 8-bit unsigned integer types. If your C compiler does not
|
||
* support 32-bit unsigned integers, this code is not
|
||
* appropriate.
|
||
*
|
||
* Caveats:
|
||
* SHA-224 and SHA-256 are designed to work with messages less
|
||
* than 2^64 bits long. This implementation uses SHA224/256Input()
|
||
* to hash the bits that are a multiple of the size of an 8-bit
|
||
* octet, and then optionally uses SHA224/256FinalBits()
|
||
* to hash the final few bits of the input.
|
||
*/
|
||
|
||
#include "pdfio-private.h"
|
||
|
||
/* Constants from sha.h */
|
||
enum {
|
||
SHA256_Message_Block_Size = 64,
|
||
SHA256HashSize = 32,
|
||
SHA256HashSizeBits = 256
|
||
};
|
||
|
||
enum {
|
||
shaSuccess = 0,
|
||
shaNull, /* Null pointer parameter */
|
||
shaInputTooLong, /* input data too long */
|
||
shaStateError, /* called Input after FinalBits or Result */
|
||
shaBadParam /* passed a bad parameter */
|
||
};
|
||
|
||
/* Macros from sha-private.h */
|
||
#define SHA_Ch(x, y, z) (((x) & ((y) ^ (z))) ^ (z))
|
||
#define SHA_Maj(x, y, z) (((x) & ((y) | (z))) | ((y) & (z)))
|
||
#define SHA_Parity(x, y, z) ((x) ^ (y) ^ (z))
|
||
|
||
/* Define the SHA shift, rotate left, and rotate right macros */
|
||
#define SHA256_SHR(bits,word) ((word) >> (bits))
|
||
#define SHA256_ROTL(bits,word) \
|
||
(((word) << (bits)) | ((word) >> (32-(bits))))
|
||
#define SHA256_ROTR(bits,word) \
|
||
(((word) >> (bits)) | ((word) << (32-(bits))))
|
||
|
||
/* Define the SHA SIGMA and sigma macros */
|
||
#define SHA256_SIGMA0(word) \
|
||
(SHA256_ROTR( 2,word) ^ SHA256_ROTR(13,word) ^ SHA256_ROTR(22,word))
|
||
#define SHA256_SIGMA1(word) \
|
||
(SHA256_ROTR( 6,word) ^ SHA256_ROTR(11,word) ^ SHA256_ROTR(25,word))
|
||
#define SHA256_sigma0(word) \
|
||
(SHA256_ROTR( 7,word) ^ SHA256_ROTR(18,word) ^ SHA256_SHR( 3,word))
|
||
#define SHA256_sigma1(word) \
|
||
(SHA256_ROTR(17,word) ^ SHA256_ROTR(19,word) ^ SHA256_SHR(10,word))
|
||
|
||
/*
|
||
* Add "length" to the length.
|
||
* Set Corrupted when overflow has occurred.
|
||
*/
|
||
static uint32_t addTemp;
|
||
#define SHA224_256AddLength(context, length) \
|
||
(addTemp = (context)->Length_Low, (context)->Corrupted = \
|
||
(((context)->Length_Low += (length)) < addTemp) && \
|
||
(++(context)->Length_High == 0) ? shaInputTooLong : \
|
||
(context)->Corrupted )
|
||
|
||
/* Local Function Prototypes */
|
||
static int SHA224_256Reset(_pdfio_sha256_t *context, uint32_t *H0);
|
||
static void SHA224_256ProcessMessageBlock(_pdfio_sha256_t *context);
|
||
static void SHA224_256Finalize(_pdfio_sha256_t *context,
|
||
uint8_t Pad_Byte);
|
||
static void SHA224_256PadMessage(_pdfio_sha256_t *context,
|
||
uint8_t Pad_Byte);
|
||
static int SHA224_256ResultN(_pdfio_sha256_t *context,
|
||
uint8_t Message_Digest[ ], int HashSize);
|
||
|
||
/* Initial Hash Values: FIPS 180-3 section 5.3.3 */
|
||
static uint32_t SHA256_H0[SHA256HashSize/4] = {
|
||
0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A,
|
||
0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19
|
||
};
|
||
|
||
/*
|
||
* _pdfioCryptoSHA256Init
|
||
*
|
||
* Description:
|
||
* This function will initialize the _pdfio_sha256_t in preparation
|
||
* for computing a new SHA256 message digest.
|
||
*
|
||
* Parameters:
|
||
* context: [in/out]
|
||
* The context to reset.
|
||
*
|
||
* Returns:
|
||
* sha Error Code.
|
||
*/
|
||
void _pdfioCryptoSHA256Init(_pdfio_sha256_t *context)
|
||
{
|
||
SHA224_256Reset(context, SHA256_H0);
|
||
}
|
||
|
||
/*
|
||
* _pdfioCryptoSHA256Append
|
||
*
|
||
* Description:
|
||
* This function accepts an array of octets as the next portion
|
||
* of the message.
|
||
*
|
||
* Parameters:
|
||
* context: [in/out]
|
||
* The SHA context to update.
|
||
* message_array[ ]: [in]
|
||
* An array of octets representing the next portion of
|
||
* the message.
|
||
* length: [in]
|
||
* The length of the message in message_array.
|
||
*
|
||
* Returns:
|
||
* sha Error Code.
|
||
*/
|
||
void
|
||
_pdfioCryptoSHA256Append(_pdfio_sha256_t *context, const uint8_t *message_array,
|
||
size_t length)
|
||
{
|
||
if (!length) return;
|
||
|
||
while (length--) {
|
||
context->Message_Block[context->Message_Block_Index++] =
|
||
*message_array;
|
||
|
||
if ((SHA224_256AddLength(context, 8) == shaSuccess) &&
|
||
(context->Message_Block_Index == SHA256_Message_Block_Size))
|
||
SHA224_256ProcessMessageBlock(context);
|
||
|
||
message_array++;
|
||
}
|
||
}
|
||
|
||
/*
|
||
* _pdfioCryptoSHA256Finish
|
||
*
|
||
* Description:
|
||
* This function will return the 256-bit message digest
|
||
* into the Message_Digest array provided by the caller.
|
||
* NOTE:
|
||
* The first octet of hash is stored in the element with index 0,
|
||
* the last octet of hash in the element with index 31.
|
||
*
|
||
* Parameters:
|
||
* context: [in/out]
|
||
* The context to use to calculate the SHA hash.
|
||
* Message_Digest[ ]: [out]
|
||
* Where the digest is returned.
|
||
*
|
||
* Returns:
|
||
* sha Error Code.
|
||
*/
|
||
void
|
||
_pdfioCryptoSHA256Finish(_pdfio_sha256_t *context,
|
||
uint8_t Message_Digest[SHA256HashSize])
|
||
{
|
||
SHA224_256ResultN(context, Message_Digest, SHA256HashSize);
|
||
}
|
||
|
||
/*
|
||
* SHA224_256Reset
|
||
*
|
||
* Description:
|
||
* This helper function will initialize the _pdfio_sha256_t in
|
||
* preparation for computing a new SHA-224 or SHA-256 message digest.
|
||
*
|
||
* Parameters:
|
||
* context: [in/out]
|
||
* The context to reset.
|
||
* H0[ ]: [in]
|
||
* The initial hash value array to use.
|
||
*
|
||
* Returns:
|
||
* sha Error Code.
|
||
*/
|
||
static int SHA224_256Reset(_pdfio_sha256_t *context, uint32_t *H0)
|
||
{
|
||
if (!context) return shaNull;
|
||
|
||
context->Length_High = context->Length_Low = 0;
|
||
context->Message_Block_Index = 0;
|
||
|
||
context->Intermediate_Hash[0] = H0[0];
|
||
context->Intermediate_Hash[1] = H0[1];
|
||
context->Intermediate_Hash[2] = H0[2];
|
||
context->Intermediate_Hash[3] = H0[3];
|
||
context->Intermediate_Hash[4] = H0[4];
|
||
context->Intermediate_Hash[5] = H0[5];
|
||
context->Intermediate_Hash[6] = H0[6];
|
||
context->Intermediate_Hash[7] = H0[7];
|
||
|
||
context->Computed = 0;
|
||
context->Corrupted = shaSuccess;
|
||
|
||
return shaSuccess;
|
||
}
|
||
|
||
/*
|
||
* SHA224_256ProcessMessageBlock
|
||
*
|
||
* Description:
|
||
* This helper function will process the next 512 bits of the
|
||
* message stored in the Message_Block array.
|
||
*
|
||
* Parameters:
|
||
* context: [in/out]
|
||
* The SHA context to update.
|
||
*
|
||
* Returns:
|
||
* Nothing.
|
||
*
|
||
* Comments:
|
||
* Many of the variable names in this code, especially the
|
||
* single character names, were used because those were the
|
||
* names used in the Secure Hash Standard.
|
||
*/
|
||
static void SHA224_256ProcessMessageBlock(_pdfio_sha256_t *context)
|
||
{
|
||
/* Constants defined in FIPS 180-3, section 4.2.2 */
|
||
static const uint32_t K[64] = {
|
||
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b,
|
||
0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01,
|
||
0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7,
|
||
0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
|
||
0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152,
|
||
0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
|
||
0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc,
|
||
0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
|
||
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819,
|
||
0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08,
|
||
0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f,
|
||
0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
|
||
0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
|
||
};
|
||
int t, t4; /* Loop counter */
|
||
uint32_t temp1, temp2; /* Temporary word value */
|
||
uint32_t W[64]; /* Word sequence */
|
||
uint32_t A, B, C, D, E, F, G, H; /* Word buffers */
|
||
|
||
/*
|
||
* Initialize the first 16 words in the array W
|
||
*/
|
||
for (t = t4 = 0; t < 16; t++, t4 += 4)
|
||
W[t] = (((uint32_t)context->Message_Block[t4]) << 24) |
|
||
(((uint32_t)context->Message_Block[t4 + 1]) << 16) |
|
||
(((uint32_t)context->Message_Block[t4 + 2]) << 8) |
|
||
(((uint32_t)context->Message_Block[t4 + 3]));
|
||
|
||
for (t = 16; t < 64; t++)
|
||
W[t] = SHA256_sigma1(W[t-2]) + W[t-7] +
|
||
SHA256_sigma0(W[t-15]) + W[t-16];
|
||
|
||
A = context->Intermediate_Hash[0];
|
||
B = context->Intermediate_Hash[1];
|
||
C = context->Intermediate_Hash[2];
|
||
D = context->Intermediate_Hash[3];
|
||
E = context->Intermediate_Hash[4];
|
||
F = context->Intermediate_Hash[5];
|
||
G = context->Intermediate_Hash[6];
|
||
H = context->Intermediate_Hash[7];
|
||
|
||
for (t = 0; t < 64; t++) {
|
||
temp1 = H + SHA256_SIGMA1(E) + SHA_Ch(E,F,G) + K[t] + W[t];
|
||
temp2 = SHA256_SIGMA0(A) + SHA_Maj(A,B,C);
|
||
H = G;
|
||
G = F;
|
||
F = E;
|
||
E = D + temp1;
|
||
D = C;
|
||
C = B;
|
||
B = A;
|
||
A = temp1 + temp2;
|
||
}
|
||
|
||
context->Intermediate_Hash[0] += A;
|
||
context->Intermediate_Hash[1] += B;
|
||
context->Intermediate_Hash[2] += C;
|
||
context->Intermediate_Hash[3] += D;
|
||
context->Intermediate_Hash[4] += E;
|
||
context->Intermediate_Hash[5] += F;
|
||
context->Intermediate_Hash[6] += G;
|
||
context->Intermediate_Hash[7] += H;
|
||
|
||
context->Message_Block_Index = 0;
|
||
}
|
||
|
||
/*
|
||
* SHA224_256Finalize
|
||
*
|
||
* Description:
|
||
* This helper function finishes off the digest calculations.
|
||
*
|
||
* Parameters:
|
||
* context: [in/out]
|
||
* The SHA context to update.
|
||
* Pad_Byte: [in]
|
||
* The last byte to add to the message block before the 0-padding
|
||
* and length. This will contain the last bits of the message
|
||
* followed by another single bit. If the message was an
|
||
* exact multiple of 8-bits long, Pad_Byte will be 0x80.
|
||
*
|
||
* Returns:
|
||
* sha Error Code.
|
||
*/
|
||
static void SHA224_256Finalize(_pdfio_sha256_t *context,
|
||
uint8_t Pad_Byte)
|
||
{
|
||
int i;
|
||
SHA224_256PadMessage(context, Pad_Byte);
|
||
/* message may be sensitive, so clear it out */
|
||
for (i = 0; i < SHA256_Message_Block_Size; ++i)
|
||
context->Message_Block[i] = 0;
|
||
context->Length_High = 0; /* and clear length */
|
||
context->Length_Low = 0;
|
||
context->Computed = 1;
|
||
}
|
||
|
||
/*
|
||
* SHA224_256PadMessage
|
||
*
|
||
* Description:
|
||
* According to the standard, the message must be padded to the next
|
||
* even multiple of 512 bits. The first padding bit must be a '1'.
|
||
* The last 64 bits represent the length of the original message.
|
||
* All bits in between should be 0. This helper function will pad
|
||
* the message according to those rules by filling the
|
||
* Message_Block array accordingly. When it returns, it can be
|
||
* assumed that the message digest has been computed.
|
||
*
|
||
* Parameters:
|
||
* context: [in/out]
|
||
* The context to pad.
|
||
* Pad_Byte: [in]
|
||
* The last byte to add to the message block before the 0-padding
|
||
* and length. This will contain the last bits of the message
|
||
* followed by another single bit. If the message was an
|
||
* exact multiple of 8-bits long, Pad_Byte will be 0x80.
|
||
*
|
||
* Returns:
|
||
* Nothing.
|
||
*/
|
||
static void SHA224_256PadMessage(_pdfio_sha256_t *context,
|
||
uint8_t Pad_Byte)
|
||
{
|
||
/*
|
||
* Check to see if the current message block is too small to hold
|
||
* the initial padding bits and length. If so, we will pad the
|
||
* block, process it, and then continue padding into a second
|
||
* block.
|
||
*/
|
||
if (context->Message_Block_Index >= (SHA256_Message_Block_Size-8)) {
|
||
context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
|
||
while (context->Message_Block_Index < SHA256_Message_Block_Size)
|
||
context->Message_Block[context->Message_Block_Index++] = 0;
|
||
SHA224_256ProcessMessageBlock(context);
|
||
} else
|
||
context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
|
||
|
||
while (context->Message_Block_Index < (SHA256_Message_Block_Size-8))
|
||
context->Message_Block[context->Message_Block_Index++] = 0;
|
||
|
||
/*
|
||
* Store the message length as the last 8 octets
|
||
*/
|
||
context->Message_Block[56] = (uint8_t)(context->Length_High >> 24);
|
||
context->Message_Block[57] = (uint8_t)(context->Length_High >> 16);
|
||
context->Message_Block[58] = (uint8_t)(context->Length_High >> 8);
|
||
context->Message_Block[59] = (uint8_t)(context->Length_High);
|
||
context->Message_Block[60] = (uint8_t)(context->Length_Low >> 24);
|
||
context->Message_Block[61] = (uint8_t)(context->Length_Low >> 16);
|
||
context->Message_Block[62] = (uint8_t)(context->Length_Low >> 8);
|
||
context->Message_Block[63] = (uint8_t)(context->Length_Low);
|
||
|
||
SHA224_256ProcessMessageBlock(context);
|
||
}
|
||
|
||
/*
|
||
* SHA224_256ResultN
|
||
*
|
||
* Description:
|
||
* This helper function will return the 224-bit or 256-bit message
|
||
* digest into the Message_Digest array provided by the caller.
|
||
* NOTE:
|
||
* The first octet of hash is stored in the element with index 0,
|
||
* the last octet of hash in the element with index 27/31.
|
||
*
|
||
* Parameters:
|
||
* context: [in/out]
|
||
* The context to use to calculate the SHA hash.
|
||
* Message_Digest[ ]: [out]
|
||
* Where the digest is returned.
|
||
* HashSize: [in]
|
||
* The size of the hash, either 28 or 32.
|
||
*
|
||
* Returns:
|
||
* sha Error Code.
|
||
*/
|
||
static int SHA224_256ResultN(_pdfio_sha256_t *context,
|
||
uint8_t Message_Digest[ ], int HashSize)
|
||
{
|
||
int i;
|
||
|
||
if (!context) return shaNull;
|
||
if (!Message_Digest) return shaNull;
|
||
if (context->Corrupted) return context->Corrupted;
|
||
|
||
if (!context->Computed)
|
||
SHA224_256Finalize(context, 0x80);
|
||
|
||
for (i = 0; i < HashSize; ++i)
|
||
Message_Digest[i] = (uint8_t)
|
||
(context->Intermediate_Hash[i>>2] >> 8 * ( 3 - ( i & 0x03 ) ));
|
||
|
||
return shaSuccess;
|
||
}
|