diff options
Diffstat (limited to 'core/fpdfapi/parser/cpdf_crypto_handler.cpp')
| -rw-r--r-- | core/fpdfapi/parser/cpdf_crypto_handler.cpp | 342 |
1 files changed, 342 insertions, 0 deletions
diff --git a/core/fpdfapi/parser/cpdf_crypto_handler.cpp b/core/fpdfapi/parser/cpdf_crypto_handler.cpp new file mode 100644 index 0000000000..f7dc19e243 --- /dev/null +++ b/core/fpdfapi/parser/cpdf_crypto_handler.cpp @@ -0,0 +1,342 @@ +// Copyright 2014 PDFium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com + +#include "core/fpdfapi/parser/cpdf_crypto_handler.h" + +#include <time.h> + +#include "core/fdrm/crypto/fx_crypt.h" +#include "core/fpdfapi/parser/cpdf_parser.h" +#include "core/fpdfapi/parser/cpdf_security_handler.h" +#include "core/fpdfapi/parser/cpdf_simple_parser.h" + +void CPDF_CryptoHandler::CryptBlock(FX_BOOL bEncrypt, + uint32_t objnum, + uint32_t gennum, + const uint8_t* src_buf, + uint32_t src_size, + uint8_t* dest_buf, + uint32_t& dest_size) { + if (m_Cipher == FXCIPHER_NONE) { + FXSYS_memcpy(dest_buf, src_buf, src_size); + return; + } + uint8_t realkey[16]; + int realkeylen = 16; + if (m_Cipher != FXCIPHER_AES || m_KeyLen != 32) { + uint8_t key1[32]; + PopulateKey(objnum, gennum, key1); + + if (m_Cipher == FXCIPHER_AES) { + FXSYS_memcpy(key1 + m_KeyLen + 5, "sAlT", 4); + } + CRYPT_MD5Generate( + key1, m_Cipher == FXCIPHER_AES ? m_KeyLen + 9 : m_KeyLen + 5, realkey); + realkeylen = m_KeyLen + 5; + if (realkeylen > 16) { + realkeylen = 16; + } + } + if (m_Cipher == FXCIPHER_AES) { + CRYPT_AESSetKey(m_pAESContext, 16, m_KeyLen == 32 ? m_EncryptKey : realkey, + m_KeyLen, bEncrypt); + if (bEncrypt) { + uint8_t iv[16]; + for (int i = 0; i < 16; i++) { + iv[i] = (uint8_t)rand(); + } + CRYPT_AESSetIV(m_pAESContext, iv); + FXSYS_memcpy(dest_buf, iv, 16); + int nblocks = src_size / 16; + CRYPT_AESEncrypt(m_pAESContext, dest_buf + 16, src_buf, nblocks * 16); + uint8_t padding[16]; + FXSYS_memcpy(padding, src_buf + nblocks * 16, src_size % 16); + FXSYS_memset(padding + src_size % 16, 16 - src_size % 16, + 16 - src_size % 16); + CRYPT_AESEncrypt(m_pAESContext, dest_buf + nblocks * 16 + 16, padding, + 16); + dest_size = 32 + nblocks * 16; + } else { + CRYPT_AESSetIV(m_pAESContext, src_buf); + CRYPT_AESDecrypt(m_pAESContext, dest_buf, src_buf + 16, src_size - 16); + dest_size = src_size - 16; + dest_size -= dest_buf[dest_size - 1]; + } + } else { + ASSERT(dest_size == src_size); + if (dest_buf != src_buf) { + FXSYS_memcpy(dest_buf, src_buf, src_size); + } + CRYPT_ArcFourCryptBlock(dest_buf, dest_size, realkey, realkeylen); + } +} + +struct AESCryptContext { + uint8_t m_Context[2048]; + FX_BOOL m_bIV; + uint8_t m_Block[16]; + uint32_t m_BlockOffset; +}; + +void* CPDF_CryptoHandler::CryptStart(uint32_t objnum, + uint32_t gennum, + FX_BOOL bEncrypt) { + if (m_Cipher == FXCIPHER_NONE) { + return this; + } + if (m_Cipher == FXCIPHER_AES && m_KeyLen == 32) { + AESCryptContext* pContext = FX_Alloc(AESCryptContext, 1); + pContext->m_bIV = TRUE; + pContext->m_BlockOffset = 0; + CRYPT_AESSetKey(pContext->m_Context, 16, m_EncryptKey, 32, bEncrypt); + if (bEncrypt) { + for (int i = 0; i < 16; i++) { + pContext->m_Block[i] = (uint8_t)rand(); + } + CRYPT_AESSetIV(pContext->m_Context, pContext->m_Block); + } + return pContext; + } + uint8_t key1[48]; + PopulateKey(objnum, gennum, key1); + + if (m_Cipher == FXCIPHER_AES) { + FXSYS_memcpy(key1 + m_KeyLen + 5, "sAlT", 4); + } + uint8_t realkey[16]; + CRYPT_MD5Generate( + key1, m_Cipher == FXCIPHER_AES ? m_KeyLen + 9 : m_KeyLen + 5, realkey); + int realkeylen = m_KeyLen + 5; + if (realkeylen > 16) { + realkeylen = 16; + } + if (m_Cipher == FXCIPHER_AES) { + AESCryptContext* pContext = FX_Alloc(AESCryptContext, 1); + pContext->m_bIV = TRUE; + pContext->m_BlockOffset = 0; + CRYPT_AESSetKey(pContext->m_Context, 16, realkey, 16, bEncrypt); + if (bEncrypt) { + for (int i = 0; i < 16; i++) { + pContext->m_Block[i] = (uint8_t)rand(); + } + CRYPT_AESSetIV(pContext->m_Context, pContext->m_Block); + } + return pContext; + } + void* pContext = FX_Alloc(uint8_t, 1040); + CRYPT_ArcFourSetup(pContext, realkey, realkeylen); + return pContext; +} + +FX_BOOL CPDF_CryptoHandler::CryptStream(void* context, + const uint8_t* src_buf, + uint32_t src_size, + CFX_BinaryBuf& dest_buf, + FX_BOOL bEncrypt) { + if (!context) { + return FALSE; + } + if (m_Cipher == FXCIPHER_NONE) { + dest_buf.AppendBlock(src_buf, src_size); + return TRUE; + } + if (m_Cipher == FXCIPHER_RC4) { + int old_size = dest_buf.GetSize(); + dest_buf.AppendBlock(src_buf, src_size); + CRYPT_ArcFourCrypt(context, dest_buf.GetBuffer() + old_size, src_size); + return TRUE; + } + AESCryptContext* pContext = (AESCryptContext*)context; + if (pContext->m_bIV && bEncrypt) { + dest_buf.AppendBlock(pContext->m_Block, 16); + pContext->m_bIV = FALSE; + } + uint32_t src_off = 0; + uint32_t src_left = src_size; + while (1) { + uint32_t copy_size = 16 - pContext->m_BlockOffset; + if (copy_size > src_left) { + copy_size = src_left; + } + FXSYS_memcpy(pContext->m_Block + pContext->m_BlockOffset, src_buf + src_off, + copy_size); + src_off += copy_size; + src_left -= copy_size; + pContext->m_BlockOffset += copy_size; + if (pContext->m_BlockOffset == 16) { + if (!bEncrypt && pContext->m_bIV) { + CRYPT_AESSetIV(pContext->m_Context, pContext->m_Block); + pContext->m_bIV = FALSE; + pContext->m_BlockOffset = 0; + } else if (src_off < src_size) { + uint8_t block_buf[16]; + if (bEncrypt) { + CRYPT_AESEncrypt(pContext->m_Context, block_buf, pContext->m_Block, + 16); + } else { + CRYPT_AESDecrypt(pContext->m_Context, block_buf, pContext->m_Block, + 16); + } + dest_buf.AppendBlock(block_buf, 16); + pContext->m_BlockOffset = 0; + } + } + if (!src_left) { + break; + } + } + return TRUE; +} +FX_BOOL CPDF_CryptoHandler::CryptFinish(void* context, + CFX_BinaryBuf& dest_buf, + FX_BOOL bEncrypt) { + if (!context) { + return FALSE; + } + if (m_Cipher == FXCIPHER_NONE) { + return TRUE; + } + if (m_Cipher == FXCIPHER_RC4) { + FX_Free(context); + return TRUE; + } + AESCryptContext* pContext = (AESCryptContext*)context; + if (bEncrypt) { + uint8_t block_buf[16]; + if (pContext->m_BlockOffset == 16) { + CRYPT_AESEncrypt(pContext->m_Context, block_buf, pContext->m_Block, 16); + dest_buf.AppendBlock(block_buf, 16); + pContext->m_BlockOffset = 0; + } + FXSYS_memset(pContext->m_Block + pContext->m_BlockOffset, + (uint8_t)(16 - pContext->m_BlockOffset), + 16 - pContext->m_BlockOffset); + CRYPT_AESEncrypt(pContext->m_Context, block_buf, pContext->m_Block, 16); + dest_buf.AppendBlock(block_buf, 16); + } else if (pContext->m_BlockOffset == 16) { + uint8_t block_buf[16]; + CRYPT_AESDecrypt(pContext->m_Context, block_buf, pContext->m_Block, 16); + if (block_buf[15] <= 16) { + dest_buf.AppendBlock(block_buf, 16 - block_buf[15]); + } + } + FX_Free(pContext); + return TRUE; +} + +void CPDF_CryptoHandler::Decrypt(uint32_t objnum, + uint32_t gennum, + CFX_ByteString& str) { + CFX_BinaryBuf dest_buf; + void* context = DecryptStart(objnum, gennum); + DecryptStream(context, str.raw_str(), str.GetLength(), dest_buf); + DecryptFinish(context, dest_buf); + str = CFX_ByteString(dest_buf.GetBuffer(), dest_buf.GetSize()); +} + +void* CPDF_CryptoHandler::DecryptStart(uint32_t objnum, uint32_t gennum) { + return CryptStart(objnum, gennum, FALSE); +} +uint32_t CPDF_CryptoHandler::DecryptGetSize(uint32_t src_size) { + return m_Cipher == FXCIPHER_AES ? src_size - 16 : src_size; +} + +FX_BOOL CPDF_CryptoHandler::Init(CPDF_Dictionary* pEncryptDict, + CPDF_SecurityHandler* pSecurityHandler) { + const uint8_t* key; + if (!pSecurityHandler->GetCryptInfo(m_Cipher, key, m_KeyLen)) { + return FALSE; + } + if (m_KeyLen > 32 || m_KeyLen < 0) { + return FALSE; + } + if (m_Cipher != FXCIPHER_NONE) { + FXSYS_memcpy(m_EncryptKey, key, m_KeyLen); + } + if (m_Cipher == FXCIPHER_AES) { + m_pAESContext = FX_Alloc(uint8_t, 2048); + } + return TRUE; +} + +FX_BOOL CPDF_CryptoHandler::Init(int cipher, const uint8_t* key, int keylen) { + if (cipher == FXCIPHER_AES) { + switch (keylen) { + case 16: + case 24: + case 32: + break; + default: + return FALSE; + } + } else if (cipher == FXCIPHER_AES2) { + if (keylen != 32) { + return FALSE; + } + } else if (cipher == FXCIPHER_RC4) { + if (keylen < 5 || keylen > 16) { + return FALSE; + } + } else { + if (keylen > 32) { + keylen = 32; + } + } + m_Cipher = cipher; + m_KeyLen = keylen; + FXSYS_memcpy(m_EncryptKey, key, keylen); + if (m_Cipher == FXCIPHER_AES) { + m_pAESContext = FX_Alloc(uint8_t, 2048); + } + return TRUE; +} +FX_BOOL CPDF_CryptoHandler::DecryptStream(void* context, + const uint8_t* src_buf, + uint32_t src_size, + CFX_BinaryBuf& dest_buf) { + return CryptStream(context, src_buf, src_size, dest_buf, FALSE); +} +FX_BOOL CPDF_CryptoHandler::DecryptFinish(void* context, + CFX_BinaryBuf& dest_buf) { + return CryptFinish(context, dest_buf, FALSE); +} +uint32_t CPDF_CryptoHandler::EncryptGetSize(uint32_t objnum, + uint32_t version, + const uint8_t* src_buf, + uint32_t src_size) { + if (m_Cipher == FXCIPHER_AES) { + return src_size + 32; + } + return src_size; +} +FX_BOOL CPDF_CryptoHandler::EncryptContent(uint32_t objnum, + uint32_t gennum, + const uint8_t* src_buf, + uint32_t src_size, + uint8_t* dest_buf, + uint32_t& dest_size) { + CryptBlock(TRUE, objnum, gennum, src_buf, src_size, dest_buf, dest_size); + return TRUE; +} +CPDF_CryptoHandler::CPDF_CryptoHandler() { + m_pAESContext = nullptr; + m_Cipher = FXCIPHER_NONE; + m_KeyLen = 0; +} +CPDF_CryptoHandler::~CPDF_CryptoHandler() { + FX_Free(m_pAESContext); +} + +void CPDF_CryptoHandler::PopulateKey(uint32_t objnum, + uint32_t gennum, + uint8_t* key) { + FXSYS_memcpy(key, m_EncryptKey, m_KeyLen); + key[m_KeyLen + 0] = (uint8_t)objnum; + key[m_KeyLen + 1] = (uint8_t)(objnum >> 8); + key[m_KeyLen + 2] = (uint8_t)(objnum >> 16); + key[m_KeyLen + 3] = (uint8_t)gennum; + key[m_KeyLen + 4] = (uint8_t)(gennum >> 8); +} |