diff --git a/Makefile b/Makefile index 467b55a..7660aa7 100644 --- a/Makefile +++ b/Makefile @@ -43,10 +43,13 @@ PUBOBJS = \ pdfio-array.o \ pdfio-common.o \ pdfio-content.o \ + pdfio-crypto.o \ pdfio-dict.o \ pdfio-file.o \ + pdfio-md5.o \ pdfio-object.o \ pdfio-page.o \ + pdfio-rc4.o \ pdfio-stream.o \ pdfio-string.o \ pdfio-token.o \ diff --git a/pdfio-crypto.c b/pdfio-crypto.c new file mode 100644 index 0000000..2a37670 --- /dev/null +++ b/pdfio-crypto.c @@ -0,0 +1,512 @@ +// +// Cryptographic functions for PDFio. +// +// Copyright © 2021 by Michael R Sweet. +// +// Licensed under Apache License v2.0. See the file "LICENSE" for more +// information. +// +// AES code is adapted from the "tiny-AES-c" project +// () +// + +// +// Include necessary headers... +// + +#include "pdfio-private.h" + + +// +// Local types... +// + +typedef uint8_t state_t[4][4]; // 4x4 AES state table + + +// +// Local globals... +// + +static const uint8_t sbox[256] = // S-box lookup table +{ + //0 1 2 3 4 5 6 7 8 9 A B C D E F + 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, + 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, + 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, + 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, + 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, + 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, + 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, + 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, + 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, + 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, + 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, + 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, + 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, + 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, + 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, + 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 +}; +static const uint8_t rsbox[256] = // Reverse S-box lookup table +{ + 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, + 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, + 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, + 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, + 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, + 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, + 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, + 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, + 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, + 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, + 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, + 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, + 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, + 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, + 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, + 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d +}; + +// The round constant word array, Rcon[i], contains the values given by +// x to the power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8) +static const uint8_t Rcon[11] = // Round constants +{ + 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 +}; + + +// +// Local functions... +// + +static void AddRoundKey(uint8_t round, state_t *state, const uint8_t *RoundKey); +static void SubBytes(state_t *state); +static void ShiftRows(state_t *state); +static uint8_t xtime(uint8_t x); +static void MixColumns(state_t *state); +static uint8_t Multiply(uint8_t x, uint8_t y); +static void InvMixColumns(state_t *state); +static void InvSubBytes(state_t *state); +static void InvShiftRows(state_t *state); +static void Cipher(state_t *state, const _pdfio_aes_t *ctx); +static void InvCipher(state_t *state, const _pdfio_aes_t *ctx); +static void XorWithIv(uint8_t *buf, const uint8_t *Iv); + + +// +// '_pdfioCryptoAESInit()' - Initialize an AES context. +// + +void +_pdfioCryptoAESInit( + _pdfio_aes_t *ctx, // I - AES context + const uint8_t *key, // I - Key + size_t keylen, // I - Length of key (must be 16 or 32) + const uint8_t *iv) // I - 16-byte initialization vector +{ + size_t i; // Looping var + uint8_t *rkptr0, // Previous round_key values + *rkptr, // Current round_key values + *rkend, // End of round_key values + tempa[4]; // Used for the column/row operations + size_t roundlen = keylen + 24; // Length of round_key + size_t nwords = keylen / 4; // Number of 32-bit words in key + + + // Clear context + memset(ctx, 0, sizeof(_pdfio_aes_t)); + + // The first round key is the key itself. + memcpy(ctx->round_key, key, keylen); + + // All other round keys are found from the previous round keys. + for (rkptr0 = ctx->round_key, rkptr = rkptr0 + keylen, rkend = rkptr + roundlen, i = nwords; rkptr < rkend; i ++) + { + if ((i % nwords) == 0) + { + // Shifts word left once - [a0,a1,a2,a3] becomes [a1,a2,a3,a0] + tempa[0] = rkptr[-3]; + tempa[1] = rkptr[-2]; + tempa[2] = rkptr[-1]; + tempa[3] = rkptr[-4]; + + // Apply the S-box to each of the four bytes to produce an output word. + tempa[0] = sbox[tempa[0]]; + tempa[1] = sbox[tempa[1]]; + tempa[2] = sbox[tempa[2]]; + tempa[3] = sbox[tempa[3]]; + + tempa[0] = tempa[0] ^ Rcon[i / nwords]; + } + else if (keylen == 32 && (i % nwords) == 4) + { + // Apply the S-box to each of the four bytes to produce an output word. + tempa[0] = sbox[rkptr[-4]]; + tempa[1] = sbox[rkptr[-3]]; + tempa[2] = sbox[rkptr[-2]]; + tempa[3] = sbox[rkptr[-1]]; + } + else + { + tempa[0] = rkptr[-4]; + tempa[1] = rkptr[-3]; + tempa[2] = rkptr[-2]; + tempa[3] = rkptr[-1]; + } + + *rkptr++ = *rkptr0++ ^ tempa[0]; + *rkptr++ = *rkptr0++ ^ tempa[1]; + *rkptr++ = *rkptr0++ ^ tempa[2]; + *rkptr++ = *rkptr0++ ^ tempa[3]; + } + + // Copy the initialization vector... + if (iv) + memcpy(ctx->iv, iv, sizeof(ctx->iv)); +} + + +// +// '_pdfioCryptoAESDecrypt()' - Decrypt a block of bytes with AES. +// + +void +_pdfioCryptoAESDecrypt( + _pdfio_aes_t *ctx, // I - AES context + uint8_t *buffer, // I - Buffer + size_t len) // I - Number of bytes to decrypt +{ + uint8_t next_iv[16]; // Next IV value + + + while (len > 15) + { + memcpy(next_iv, buffer, 16); + InvCipher((state_t *)buffer, ctx); + XorWithIv(buffer, ctx->iv); + memcpy(ctx->iv, next_iv, 16); + buffer += 16; + len -= 16; + } + + if (len > 0) + { + // Pad the final buffer with (16 - len)... + uint8_t temp[16]; // Temporary buffer + + memset(temp, 16 - len, sizeof(temp)); + memcpy(temp, buffer, len); + + memcpy(next_iv, temp, 16); + InvCipher((state_t *)temp, ctx); + XorWithIv(temp, ctx->iv); + memcpy(ctx->iv, next_iv, 16); + + memcpy(buffer, temp, len); + } +} + + +// +// '_pdfioCryptoAESEncrypt()' - Encrypt a block of bytes with AES. +// + +void +_pdfioCryptoAESEncrypt( + _pdfio_aes_t *ctx, // I - AES context + uint8_t *buffer, // I - Buffer + size_t len) // I - Number of bytes to decrypt +{ + uint8_t *iv = ctx->iv; // Current IV for CBC + uint8_t temp[16]; // Temporary buffer + + + while (len > 15) + { + XorWithIv(buffer, iv); + Cipher((state_t*)buffer, ctx); + iv = buffer; + buffer += 16; + len -= 16; + } + + if (len > 0) + { + // Pad the final buffer with (16 - len)... + memset(temp, 16 - len, sizeof(temp)); + memcpy(temp, buffer, len); + + XorWithIv(temp, iv); + Cipher((state_t*)temp, ctx); + iv = temp; + + memcpy(buffer, temp, len); + } + + /* store Iv in ctx for next call */ + memcpy(ctx->iv, iv, 16); +} + + +// This function adds the round key to state. +// The round key is added to the state by an XOR function. +static void +AddRoundKey(uint8_t round, state_t *state, const uint8_t *RoundKey) +{ + unsigned i; // Looping var + uint8_t *sptr = (*state)[0]; // Pointer into state + + + for (RoundKey += round * 16, i = 16; i > 0; i --, sptr ++, RoundKey ++) + *sptr ^= *RoundKey; +} + + +// The SubBytes Function Substitutes the values in the +// state matrix with values in an S-box. +static void +SubBytes(state_t *state) +{ + unsigned i; // Looping var + uint8_t *sptr = (*state)[0]; // Pointer into state + + + for (i = 16; i > 0; i --, sptr ++) + *sptr = sbox[*sptr]; +} + +// The ShiftRows() function shifts the rows in the state to the left. +// Each row is shifted with different offset. +// Offset = Row number. So the first row is not shifted. +static void +ShiftRows(state_t *state) +{ + uint8_t *sptr = (*state)[0]; // Pointer into state + uint8_t temp; // Temporary value + + + // Rotate first row 1 columns to left + temp = sptr[1]; + sptr[1] = sptr[5]; + sptr[5] = sptr[9]; + sptr[9] = sptr[13]; + sptr[13] = temp; + + // Rotate second row 2 columns to left + temp = sptr[2]; + sptr[2] = sptr[10]; + sptr[10] = temp; + + temp = sptr[6]; + sptr[6] = sptr[14]; + sptr[14] = temp; + + // Rotate third row 3 columns to left + temp = sptr[3]; + sptr[3] = sptr[15]; + sptr[15] = sptr[11]; + sptr[11] = sptr[7]; + sptr[7] = temp; +} + + +static uint8_t +xtime(uint8_t x) +{ + return ((x << 1) ^ ((x >> 7) * 0x1b)); +} + + +// MixColumns function mixes the columns of the state matrix +static void +MixColumns(state_t *state) +{ + unsigned i; // Looping var + uint8_t *sptr = (*state)[0]; // Pointer into state + uint8_t Tmp, Tm, t; // Temporary values + + for (i = 4; i > 0; i --, sptr += 4) + { + t = sptr[0]; + Tmp = sptr[0] ^ sptr[1] ^ sptr[2] ^ sptr[3]; + Tm = sptr[0] ^ sptr[1]; + Tm = xtime(Tm); + sptr[0] ^= Tm ^ Tmp; + + Tm = sptr[1] ^ sptr[2]; + Tm = xtime(Tm); + sptr[1] ^= Tm ^ Tmp; + + Tm = sptr[2] ^ sptr[3]; + Tm = xtime(Tm); + sptr[2] ^= Tm ^ Tmp; + + Tm = sptr[3] ^ t; + Tm = xtime(Tm); + sptr[3] ^= Tm ^ Tmp; + } +} + + +// Multiply is used to multiply numbers in the field GF(2^8) +// Note: The last call to xtime() is unneeded, but often ends up generating a smaller binary +// The compiler seems to be able to vectorize the operation better this way. +// See https://github.com/kokke/tiny-AES-c/pull/34 +static uint8_t Multiply(uint8_t x, uint8_t y) +{ + return (((y & 1) * x) ^ + ((y>>1 & 1) * xtime(x)) ^ + ((y>>2 & 1) * xtime(xtime(x))) ^ + ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^ + ((y>>4 & 1) * xtime(xtime(xtime(xtime(x)))))); /* this last call to xtime() can be omitted */ +} + + +// MixColumns function mixes the columns of the state matrix. +// The method used to multiply may be difficult to understand for the inexperienced. +// Please use the references to gain more information. +static void +InvMixColumns(state_t *state) +{ + unsigned i; // Looping var + uint8_t *sptr = (*state)[0]; // Pointer into state + uint8_t a, b, c, d; // Temporary values + + + for (i = 4; i > 0; i --) + { + a = sptr[0]; + b = sptr[1]; + c = sptr[2]; + d = sptr[3]; + + *sptr++ = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09); + *sptr++ = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d); + *sptr++ = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b); + *sptr++ = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e); + } +} + + +// The SubBytes Function Substitutes the values in the +// state matrix with values in an S-box. +static void +InvSubBytes(state_t *state) +{ + unsigned i; // Looping var + uint8_t *sptr = (*state)[0]; // Pointer into state + + + for (i = 16; i > 0; i --, sptr ++) + *sptr = rsbox[*sptr]; +} + + +static void +InvShiftRows(state_t *state) +{ + uint8_t *sptr = (*state)[0]; // Pointer into state + uint8_t temp; // Temporary value + + + // Rotate first row 1 columns to right + temp = sptr[13]; + sptr[13] = sptr[9]; + sptr[9] = sptr[5]; + sptr[5] = sptr[1]; + sptr[1] = temp; + + // Rotate second row 2 columns to right + temp = sptr[2]; + sptr[2] = sptr[10]; + sptr[10] = temp; + + temp = sptr[6]; + sptr[6] = sptr[14]; + sptr[14] = temp; + + // Rotate third row 3 columns to right + temp = sptr[3]; + sptr[3] = sptr[7]; + sptr[7] = sptr[11]; + sptr[11] = sptr[15]; + sptr[15] = temp; +} + + +// Cipher is the main function that encrypts the PlainText. +static void +Cipher(state_t *state, const _pdfio_aes_t *ctx) +{ + uint8_t round = 0; + + // Add the First round key to the state before starting the rounds. + AddRoundKey(0, state, ctx->round_key); + + // There will be Nr rounds. + // The first Nr-1 rounds are identical. + // These Nr rounds are executed in the loop below. + // Last one without MixColumns() + for (round = 1; ; ++round) + { + SubBytes(state); + ShiftRows(state); + if (round == ctx->round_size) + break; + + MixColumns(state); + AddRoundKey(round, state, ctx->round_key); + } + // Add round key to last round + AddRoundKey(ctx->round_size, state, ctx->round_key); +} + + +static void +InvCipher(state_t *state, const _pdfio_aes_t *ctx) +{ + uint8_t round = 0; + + // Add the First round key to the state before starting the rounds. + AddRoundKey(ctx->round_size, state, ctx->round_key); + + // There will be Nr rounds. + // The first Nr-1 rounds are identical. + // These Nr rounds are executed in the loop below. + // Last one without InvMixColumn() + for (round = ctx->round_size - 1; ; round --) + { + InvShiftRows(state); + InvSubBytes(state); + AddRoundKey(round, state, ctx->round_key); + + if (round == 0) + break; + + InvMixColumns(state); + } +} + + +static void +XorWithIv(uint8_t *buf, const uint8_t *Iv) +{ + // 16-byte block... + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; + *buf++ ^= *Iv++; +} diff --git a/pdfio-md5.c b/pdfio-md5.c new file mode 100644 index 0000000..2561b35 --- /dev/null +++ b/pdfio-md5.c @@ -0,0 +1,338 @@ +// +// MD5 functions for PDFio. +// +// Copyright © 2021 by Michael R Sweet. +// Copyright © 1999 Aladdin Enterprises. All rights reserved. +// +// This software is provided 'as-is', without any express or implied +// warranty. In no event will the authors be held liable for any damages +// arising from the use of this software. +// +// Permission is granted to anyone to use this software for any purpose, +// including commercial applications, and to alter it and redistribute it +// freely, subject to the following restrictions: +// +// 1. The origin of this software must not be misrepresented; you must not +// claim that you wrote the original software. If you use this software +// in a product, an acknowledgment in the product documentation would be +// appreciated but is not required. +// 2. Altered source versions must be plainly marked as such, and must not be +// misrepresented as being the original software. +// 3. This notice may not be removed or altered from any source distribution. +// +// L. Peter Deutsch +// ghost@aladdin.com +// + +#include "pdfio-private.h" + + +/* + Independent implementation of MD5 (RFC 1321). + + This code implements the MD5 Algorithm defined in RFC 1321. + It is derived directly from the text of the RFC and not from the + reference implementation. + + The original and principal author of md5.c is L. Peter Deutsch + . Other authors are noted in the change history + that follows (in reverse chronological order): + + 1999-11-04 lpd Edited comments slightly for automatic TOC extraction. + 1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5). + 1999-05-03 lpd Original version. + */ + +#define T1 0xd76aa478 +#define T2 0xe8c7b756 +#define T3 0x242070db +#define T4 0xc1bdceee +#define T5 0xf57c0faf +#define T6 0x4787c62a +#define T7 0xa8304613 +#define T8 0xfd469501 +#define T9 0x698098d8 +#define T10 0x8b44f7af +#define T11 0xffff5bb1 +#define T12 0x895cd7be +#define T13 0x6b901122 +#define T14 0xfd987193 +#define T15 0xa679438e +#define T16 0x49b40821 +#define T17 0xf61e2562 +#define T18 0xc040b340 +#define T19 0x265e5a51 +#define T20 0xe9b6c7aa +#define T21 0xd62f105d +#define T22 0x02441453 +#define T23 0xd8a1e681 +#define T24 0xe7d3fbc8 +#define T25 0x21e1cde6 +#define T26 0xc33707d6 +#define T27 0xf4d50d87 +#define T28 0x455a14ed +#define T29 0xa9e3e905 +#define T30 0xfcefa3f8 +#define T31 0x676f02d9 +#define T32 0x8d2a4c8a +#define T33 0xfffa3942 +#define T34 0x8771f681 +#define T35 0x6d9d6122 +#define T36 0xfde5380c +#define T37 0xa4beea44 +#define T38 0x4bdecfa9 +#define T39 0xf6bb4b60 +#define T40 0xbebfbc70 +#define T41 0x289b7ec6 +#define T42 0xeaa127fa +#define T43 0xd4ef3085 +#define T44 0x04881d05 +#define T45 0xd9d4d039 +#define T46 0xe6db99e5 +#define T47 0x1fa27cf8 +#define T48 0xc4ac5665 +#define T49 0xf4292244 +#define T50 0x432aff97 +#define T51 0xab9423a7 +#define T52 0xfc93a039 +#define T53 0x655b59c3 +#define T54 0x8f0ccc92 +#define T55 0xffeff47d +#define T56 0x85845dd1 +#define T57 0x6fa87e4f +#define T58 0xfe2ce6e0 +#define T59 0xa3014314 +#define T60 0x4e0811a1 +#define T61 0xf7537e82 +#define T62 0xbd3af235 +#define T63 0x2ad7d2bb +#define T64 0xeb86d391 + +static void +md5_process(_pdfio_md5_t *pms, const uint8_t *data /*[64]*/) +{ + uint32_t + a = pms->abcd[0], b = pms->abcd[1], + c = pms->abcd[2], d = pms->abcd[3]; + uint32_t t; + +#ifndef ARCH_IS_BIG_ENDIAN +# define ARCH_IS_BIG_ENDIAN 1 /* slower, default implementation */ +#endif +#if ARCH_IS_BIG_ENDIAN + + /* + * On big-endian machines, we must arrange the bytes in the right + * order. (This also works on machines of unknown byte order.) + */ + uint32_t X[16]; + const uint8_t *xp = data; + int i; + + for (i = 0; i < 16; ++i, xp += 4) + X[i] = xp[0] + (unsigned)(xp[1] << 8) + (unsigned)(xp[2] << 16) + (unsigned)(xp[3] << 24); + +#else /* !ARCH_IS_BIG_ENDIAN */ + + /* + * On little-endian machines, we can process properly aligned data + * without copying it. + */ + uint32_t xbuf[16]; + const uint32_t *X; + + if (!((data - (const uint8_t *)0) & 3)) { + /* data are properly aligned */ + X = (const uint32_t *)data; + } else { + /* not aligned */ + memcpy(xbuf, data, 64); + X = xbuf; + } +#endif + +#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n)))) + + /* Round 1. */ + /* Let [abcd k s i] denote the operation + a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */ +#define F(x, y, z) (((x) & (y)) | (~(x) & (z))) +#define SET(a, b, c, d, k, s, Ti)\ + t = a + F(b,c,d) + X[k] + Ti;\ + a = ROTATE_LEFT(t, s) + b + /* Do the following 16 operations. */ + SET(a, b, c, d, 0, 7, T1); + SET(d, a, b, c, 1, 12, T2); + SET(c, d, a, b, 2, 17, T3); + SET(b, c, d, a, 3, 22, T4); + SET(a, b, c, d, 4, 7, T5); + SET(d, a, b, c, 5, 12, T6); + SET(c, d, a, b, 6, 17, T7); + SET(b, c, d, a, 7, 22, T8); + SET(a, b, c, d, 8, 7, T9); + SET(d, a, b, c, 9, 12, T10); + SET(c, d, a, b, 10, 17, T11); + SET(b, c, d, a, 11, 22, T12); + SET(a, b, c, d, 12, 7, T13); + SET(d, a, b, c, 13, 12, T14); + SET(c, d, a, b, 14, 17, T15); + SET(b, c, d, a, 15, 22, T16); +#undef SET + + /* Round 2. */ + /* Let [abcd k s i] denote the operation + a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */ +#define G(x, y, z) (((x) & (z)) | ((y) & ~(z))) +#define SET(a, b, c, d, k, s, Ti)\ + t = a + G(b,c,d) + X[k] + Ti;\ + a = ROTATE_LEFT(t, s) + b + /* Do the following 16 operations. */ + SET(a, b, c, d, 1, 5, T17); + SET(d, a, b, c, 6, 9, T18); + SET(c, d, a, b, 11, 14, T19); + SET(b, c, d, a, 0, 20, T20); + SET(a, b, c, d, 5, 5, T21); + SET(d, a, b, c, 10, 9, T22); + SET(c, d, a, b, 15, 14, T23); + SET(b, c, d, a, 4, 20, T24); + SET(a, b, c, d, 9, 5, T25); + SET(d, a, b, c, 14, 9, T26); + SET(c, d, a, b, 3, 14, T27); + SET(b, c, d, a, 8, 20, T28); + SET(a, b, c, d, 13, 5, T29); + SET(d, a, b, c, 2, 9, T30); + SET(c, d, a, b, 7, 14, T31); + SET(b, c, d, a, 12, 20, T32); +#undef SET + + /* Round 3. */ + /* Let [abcd k s t] denote the operation + a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */ +#define H(x, y, z) ((x) ^ (y) ^ (z)) +#define SET(a, b, c, d, k, s, Ti)\ + t = a + H(b,c,d) + X[k] + Ti;\ + a = ROTATE_LEFT(t, s) + b + /* Do the following 16 operations. */ + SET(a, b, c, d, 5, 4, T33); + SET(d, a, b, c, 8, 11, T34); + SET(c, d, a, b, 11, 16, T35); + SET(b, c, d, a, 14, 23, T36); + SET(a, b, c, d, 1, 4, T37); + SET(d, a, b, c, 4, 11, T38); + SET(c, d, a, b, 7, 16, T39); + SET(b, c, d, a, 10, 23, T40); + SET(a, b, c, d, 13, 4, T41); + SET(d, a, b, c, 0, 11, T42); + SET(c, d, a, b, 3, 16, T43); + SET(b, c, d, a, 6, 23, T44); + SET(a, b, c, d, 9, 4, T45); + SET(d, a, b, c, 12, 11, T46); + SET(c, d, a, b, 15, 16, T47); + SET(b, c, d, a, 2, 23, T48); +#undef SET + + /* Round 4. */ + /* Let [abcd k s t] denote the operation + a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */ +#define I(x, y, z) ((y) ^ ((x) | ~(z))) +#define SET(a, b, c, d, k, s, Ti)\ + t = a + I(b,c,d) + X[k] + Ti;\ + a = ROTATE_LEFT(t, s) + b + /* Do the following 16 operations. */ + SET(a, b, c, d, 0, 6, T49); + SET(d, a, b, c, 7, 10, T50); + SET(c, d, a, b, 14, 15, T51); + SET(b, c, d, a, 5, 21, T52); + SET(a, b, c, d, 12, 6, T53); + SET(d, a, b, c, 3, 10, T54); + SET(c, d, a, b, 10, 15, T55); + SET(b, c, d, a, 1, 21, T56); + SET(a, b, c, d, 8, 6, T57); + SET(d, a, b, c, 15, 10, T58); + SET(c, d, a, b, 6, 15, T59); + SET(b, c, d, a, 13, 21, T60); + SET(a, b, c, d, 4, 6, T61); + SET(d, a, b, c, 11, 10, T62); + SET(c, d, a, b, 2, 15, T63); + SET(b, c, d, a, 9, 21, T64); +#undef SET + + /* Then perform the following additions. (That is increment each + of the four registers by the value it had before this block + was started.) */ + pms->abcd[0] += a; + pms->abcd[1] += b; + pms->abcd[2] += c; + pms->abcd[3] += d; +} + +void +_pdfioCryptoMD5Init(_pdfio_md5_t *pms) +{ + pms->count[0] = pms->count[1] = 0; + pms->abcd[0] = 0x67452301; + pms->abcd[1] = 0xefcdab89; + pms->abcd[2] = 0x98badcfe; + pms->abcd[3] = 0x10325476; +} + +void +_pdfioCryptoMD5Append(_pdfio_md5_t *pms, const uint8_t *data, size_t nbytes) +{ + const uint8_t *p = data; + size_t left = nbytes; + int offset = (pms->count[0] >> 3) & 63; + uint32_t nbits = (uint32_t)(nbytes << 3); + + if (nbytes == 0) + return; + + /* Update the message length. */ + pms->count[1] += (unsigned)(nbytes >> 29); + pms->count[0] += nbits; + if (pms->count[0] < nbits) + pms->count[1]++; + + /* Process an initial partial block. */ + if (offset) { + int copy = (offset + nbytes > 64 ? 64 - offset : nbytes); + + memcpy(pms->buf + offset, p, copy); + if (offset + copy < 64) + return; + p += copy; + left -= copy; + md5_process(pms, pms->buf); + } + + /* Process full blocks. */ + for (; left >= 64; p += 64, left -= 64) + md5_process(pms, p); + + /* Process a final partial block. */ + if (left) + memcpy(pms->buf, p, left); +} + +void +_pdfioCryptoMD5Finish(_pdfio_md5_t *pms, uint8_t digest[16]) +{ + static const uint8_t pad[64] = { + 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + }; + uint8_t data[8]; + int i; + + /* Save the length before padding. */ + for (i = 0; i < 8; ++i) + data[i] = (uint8_t)(pms->count[i >> 2] >> ((i & 3) << 3)); + /* Pad to 56 bytes mod 64. */ + _pdfioCryptoMD5Append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1); + /* Append the length. */ + _pdfioCryptoMD5Append(pms, data, 8); + for (i = 0; i < 16; ++i) + digest[i] = (uint8_t)(pms->abcd[i >> 2] >> ((i & 3) << 3)); +} diff --git a/pdfio-private.h b/pdfio-private.h index 34d41c3..b359863 100644 --- a/pdfio-private.h +++ b/pdfio-private.h @@ -24,6 +24,7 @@ # include "pdfio.h" # include +# include # include # include # include @@ -174,6 +175,28 @@ typedef struct _pdfio_value_s // Value structure } value; // Value union } _pdfio_value_t; + +typedef struct _pdfio_aes_s // AES encryption state +{ + size_t round_size; // Size of round key + uint8_t round_key[240], // Round key + iv[16]; // Initialization vector +} _pdfio_aes_t; + +typedef struct _pdfio_md5_s // MD5 hash state +{ + uint32_t count[2]; // Message length in bits, lsw first + uint32_t abcd[4]; // Digest buffer + uint8_t buf[64]; // Accumulate block +} _pdfio_md5_t; + +typedef struct _pdfio_rc4_s // RC4 encryption state +{ + uint8_t sbox[256]; // S boxes for encryption + uint8_t i, j; // Current indices into S boxes +} _pdfio_rc4_t; + + struct _pdfio_array_s { pdfio_file_t *pdf; // PDF file @@ -294,6 +317,15 @@ extern _pdfio_value_t *_pdfioArrayGetValue(pdfio_array_t *a, size_t n) _PDFIO_IN extern pdfio_array_t *_pdfioArrayRead(pdfio_file_t *pdf, _pdfio_token_t *ts) _PDFIO_INTERNAL; extern bool _pdfioArrayWrite(pdfio_array_t *a) _PDFIO_INTERNAL; +extern void _pdfioCryptoAESInit(_pdfio_aes_t *ctx, const uint8_t *key, size_t keylen, const uint8_t *iv) _PDFIO_INTERNAL; +extern void _pdfioCryptoAESDecrypt(_pdfio_aes_t *ctx, uint8_t *buffer, size_t len) _PDFIO_INTERNAL; +extern void _pdfioCryptoAESEncrypt(_pdfio_aes_t *ctx, uint8_t *buffer, size_t len) _PDFIO_INTERNAL; +extern void _pdfioCryptoMD5Append(_pdfio_md5_t *pms, const uint8_t *data, size_t nbytes) _PDFIO_INTERNAL; +extern void _pdfioCryptoMD5Finish(_pdfio_md5_t *pms, uint8_t digest[16]) _PDFIO_INTERNAL; +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 _pdfioDictDebug(pdfio_dict_t *dict, FILE *fp) _PDFIO_INTERNAL; extern void _pdfioDictDelete(pdfio_dict_t *dict) _PDFIO_INTERNAL; extern _pdfio_value_t *_pdfioDictGetValue(pdfio_dict_t *dict, const char *key) _PDFIO_INTERNAL; diff --git a/pdfio-rc4.c b/pdfio-rc4.c new file mode 100644 index 0000000..69d9a96 --- /dev/null +++ b/pdfio-rc4.c @@ -0,0 +1,107 @@ +// +// RC4 functions for PDFio. +// +// Copyright © 2021 by Michael R Sweet. +// +// Original code by Tim Martin +// Copyright © 1999 by Carnegie Mellon University, All Rights Reserved +// +// Permission to use, copy, modify, and distribute this software and its +// documentation for any purpose and without fee is hereby granted, +// provided that the above copyright notice appear in all copies and that +// both that copyright notice and this permission notice appear in +// supporting documentation, and that the name of Carnegie Mellon +// University not be used in advertising or publicity pertaining to +// distribution of the software without specific, written prior +// permission. +// +// CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO +// THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND +// FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE FOR +// ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT +// OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +// + +#include "pdfio-private.h" + + +// +// '_pdfioCryptoRC4Init()' - Initialize an RC4 context with the specified key. +// + +void +_pdfioCryptoRC4Init( + _pdfio_rc4_t *ctx, // IO - Context + const uint8_t *key, // I - Key + size_t keylen) // I - Length of key +{ + size_t i; // Looping var + uint8_t j, // S box counter + tmp; // Temporary variable + + + // Fill in linearly s0=0, s1=1, ... + for (i = 0; i < 256; i ++) + ctx->sbox[i] = (uint8_t)i; + + for (i = 0, j = 0; i < 256; i ++) + { + // j = (j + Si + Ki) mod 256 + j += ctx->sbox[i] + key[i % keylen]; + + // Swap Si and Sj... + tmp = ctx->sbox[i]; + ctx->sbox[i] = ctx->sbox[j]; + ctx->sbox[j] = tmp; + } + + // Initialize counters to 0 and return... + ctx->i = 0; + ctx->j = 0; +} + + +// +// '_pdfioCryptoRC4Crypt()' - De/encrypt the given buffer. +// + +void +_pdfioCryptoRC4Crypt( + _pdfio_rc4_t *ctx, // I - Context + uint8_t *buffer, // I - Buffer + size_t len) // I - Size of buffers +{ + uint8_t tmp, // Swap variable + i, j, // Looping vars + t; // Current S box + + + // Loop through the entire buffer... + i = ctx->i; + j = ctx->j; + + while (len > 0) + { + // Get the next S box indices... + i ++; + j += ctx->sbox[i]; + + // Swap Si and Sj... + tmp = ctx->sbox[i]; + ctx->sbox[i] = ctx->sbox[j]; + ctx->sbox[j] = tmp; + + // Get the S box index for this byte... + t = ctx->sbox[i] + ctx->sbox[j]; + + // Encrypt using the S box... + *buffer++ ^= ctx->sbox[t]; + len --; + } + + // Copy current S box indices back to context... + ctx->i = i; + ctx->j = j; +}