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Add SHA-256 code from RFC 6234.

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Michael R Sweet 2021-10-08 18:55:25 -04:00
parent 8aef2bfedd
commit 9c05f802fc
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1
Makefile
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@ -50,6 +50,7 @@ PUBOBJS = \
pdfio-object.o \
pdfio-page.o \
pdfio-rc4.o \
pdfio-sha256.o \
pdfio-stream.o \
pdfio-string.o \
pdfio-token.o \

13
pdfio-private.h
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@ -196,6 +196,16 @@ typedef struct _pdfio_rc4_s // RC4 encryption state
uint8_t i, j; // Current indices into S boxes
} _pdfio_rc4_t;
typedef struct _pdfio_sha265_s // SHA-256 hash state
{
uint32_t Intermediate_Hash[8]; // Message Digest
uint32_t Length_High; // Message length in bits
uint32_t Length_Low; // Message length in bits
int Message_Block_Index; // Message_Block array index
uint8_t Message_Block[64]; // 512-bit message blocks
int Computed; // Is the hash computed?
int Corrupted; // Cumulative corruption code
} _pdfio_sha256_t;
struct _pdfio_array_s
{
@ -325,6 +335,9 @@ extern void _pdfioCryptoMD5Finish(_pdfio_md5_t *pms, uint8_t digest[16]) _PDFIO
extern void _pdfioCryptoMD5Init(_pdfio_md5_t *pms) _PDFIO_INTERNAL;
extern void _pdfioCryptoRC4Init(_pdfio_rc4_t *ctx, const uint8_t *key, size_t keylen) _PDFIO_INTERNAL;
extern void _pdfioCryptoRC4Crypt(_pdfio_rc4_t *ctx, uint8_t *buffer, size_t len) _PDFIO_INTERNAL;
extern void _pdfioCryptoSHA256Append(_pdfio_sha256_t *, const uint8_t *bytes, size_t bytecount) _PDFIO_INTERNAL;
extern void _pdfioCryptoSHA256Init(_pdfio_sha256_t *ctx) _PDFIO_INTERNAL;
extern void _pdfioCryptoSHA256Finish(_pdfio_sha256_t *ctx, uint8_t *Message_Digest) _PDFIO_INTERNAL;
extern void _pdfioDictDebug(pdfio_dict_t *dict, FILE *fp) _PDFIO_INTERNAL;
extern void _pdfioDictDelete(pdfio_dict_t *dict) _PDFIO_INTERNAL;

480
pdfio-sha256.c Normal file
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@ -0,0 +1,480 @@
//
// 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;
}