diff --git a/Makefile b/Makefile index 7660aa7..87c71d1 100644 --- a/Makefile +++ b/Makefile @@ -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 \ diff --git a/pdfio-private.h b/pdfio-private.h index b359863..df2e36b 100644 --- a/pdfio-private.h +++ b/pdfio-private.h @@ -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; diff --git a/pdfio-sha256.c b/pdfio-sha256.c new file mode 100644 index 0000000..8bea533 --- /dev/null +++ b/pdfio-sha256.c @@ -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 (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; +}