X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/c38e3ce98599a410a47dc10253faa4d5830f13b2..427c49bcad63d042b29ada2ac27e3dfc4845c779:/libsecurity_ssl/lib/ssl3RecordCallouts.c diff --git a/libsecurity_ssl/lib/ssl3RecordCallouts.c b/libsecurity_ssl/lib/ssl3RecordCallouts.c new file mode 100644 index 00000000..e9604f49 --- /dev/null +++ b/libsecurity_ssl/lib/ssl3RecordCallouts.c @@ -0,0 +1,440 @@ +/* + * Copyright (c) 2002,2005-2007,2010-2011 Apple Inc. All Rights Reserved. + * + * @APPLE_LICENSE_HEADER_START@ + * + * This file contains Original Code and/or Modifications of Original Code + * as defined in and that are subject to the Apple Public Source License + * Version 2.0 (the 'License'). You may not use this file except in + * compliance with the License. Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this + * file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, + * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * Please see the License for the specific language governing rights and + * limitations under the License. + * + * @APPLE_LICENSE_HEADER_END@ + */ + +/* + * ssl3RecordCallouts.c - SSLv3-specific routines for SslTlsCallouts. + */ + +/* THIS FILE CONTAINS KERNEL CODE */ + +#include +#include +#include +#include + +#ifdef KERNEL +#include +#else +#include +#endif + +#include "sslDebug.h" +#include "sslMemory.h" +#include "sslUtils.h" +#include "sslRand.h" + +#include "tls_record.h" + + +/* + * ssl3WriteRecord does not send alerts on failure, out of the assumption/fear + * that this might result in a loop (since sending an alert causes ssl3WriteRecord + * to be called). + * + * As far as I can tell, we can use this same routine for SSLv3 and TLSv1, as long + * as we're not trying to use the "variable length padding" feature of TLSv1. + * OpenSSL doesn't use that feature; for now, neither will we. Thus this routine + * is used for the SslTlsCallouts.writeRecord function for both protocols. + */ +int ssl3WriteRecord( + SSLRecord rec, + struct SSLRecordInternalContext *ctx) +{ + int err; + int padding = 0, i; + WaitingRecord *out = NULL, *queue; + SSLBuffer payload, mac; + uint8_t *charPtr; + uint16_t payloadSize,blockSize = 0; + int head = 5; + + switch(rec.protocolVersion) { + case DTLS_Version_1_0: + head += 8; + case SSL_Version_3_0: + case TLS_Version_1_0: + case TLS_Version_1_1: + case TLS_Version_1_2: + break; + default: + check(0); + return errSSLRecordInternal; + } + check(rec.contents.length <= 16384); + + sslLogRecordIo("type = %02x, ver = %04x, len = %ld, seq = %016llx", + rec.contentType, rec.protocolVersion, rec.contents.length, + ctx->writeCipher.sequenceNum); + + /* Allocate enough room for the transmitted record, which will be: + * 5 bytes of header (13 for DTLS) + + * IV [block cipher and TLS1.1 or DTLS 1.0 only] + * encrypted contents + + * macLength + + * padding [block ciphers only] + + * padding length field (1 byte) [block ciphers only] + */ + payloadSize = (uint16_t) rec.contents.length; + CipherType cipherType = ctx->writeCipher.symCipher->params->cipherType; + const Cipher *cipher = &ctx->writeCipher.symCipher->c.cipher; + const AEADCipher *aead = &ctx->writeCipher.symCipher->c.aead; + blockSize = ctx->writeCipher.symCipher->params->blockSize; + switch (cipherType) { + case blockCipherType: + payloadSize += ctx->writeCipher.macRef->hash->digestSize; + padding = blockSize - (payloadSize % blockSize) - 1; + payloadSize += padding + 1; + /* TLS 1.1, TLS1.2 and DTLS 1.0 have an extra block for IV */ + if(ctx->negProtocolVersion >= TLS_Version_1_1) { + payloadSize += blockSize; + } + break; + case streamCipherType: + payloadSize += ctx->writeCipher.macRef->hash->digestSize; + break; + case aeadCipherType: + /* AES_GCM doesn't need padding. */ + payloadSize += aead->macSize; + break; + default: + check(0); + return errSSLRecordInternal; + } + + out = (WaitingRecord *)sslMalloc(offsetof(WaitingRecord, data) + + head + payloadSize); + out->next = NULL; + out->sent = 0; + out->length = head + payloadSize; + + charPtr = out->data; + *(charPtr++) = rec.contentType; + charPtr = SSLEncodeInt(charPtr, rec.protocolVersion, 2); + + /* DTLS sequence number */ + if(rec.protocolVersion == DTLS_Version_1_0) + charPtr = SSLEncodeUInt64(charPtr,ctx->writeCipher.sequenceNum); + + charPtr = SSLEncodeInt(charPtr, payloadSize, 2); + + /* Also for DTLS */ + if((ctx->negProtocolVersion >= TLS_Version_1_1) && + (cipherType == blockCipherType)) + { + SSLBuffer randomIV; + randomIV.data = charPtr; + randomIV.length = blockSize; + if((err = sslRand(&randomIV)) != 0) + return err; + charPtr += blockSize; + } + if (cipherType == aeadCipherType) { + /* Encode the explicit iv, for AES_GCM we just use the 8 byte + sequenceNum as the explicitIV. + Ideally this needs to be done in the algorithm itself, by an + extra function pointer in AEADCipher. */ + charPtr = SSLEncodeUInt64(charPtr,ctx->writeCipher.sequenceNum); + /* TODO: If we ever add any mode other than GCM this code might have + to be different. */ + /* TODO: Pass 4 byte implicit and 8 byte explicit IV to cipher */ + //err = ctx->writeCipher.symCipher->c.aead.setIV(charPtr, &ctx->writeCipher, ctx); + } + + /* Copy the contents into the output buffer */ + memcpy(charPtr, rec.contents.data, rec.contents.length); + payload.data = charPtr; + payload.length = rec.contents.length; + + charPtr += rec.contents.length; + + /* MAC the data */ + if (cipherType != aeadCipherType) { + /* MAC immediately follows data */ + mac.data = charPtr; + mac.length = ctx->writeCipher.macRef->hash->digestSize; + charPtr += mac.length; + if (mac.length > 0) /* Optimize away null case */ + { + check(ctx->sslTslCalls != NULL); + if ((err = ctx->sslTslCalls->computeMac(rec.contentType, + payload, + mac, + &ctx->writeCipher, + ctx->writeCipher.sequenceNum, + ctx)) != 0) + goto fail; + } + } + + /* For TLS 1.1 and DTLS, we would need to specifiy the IV, but instead + we are clever like this: since the IV is just one block in front, + we encrypt it with the rest of the data. The actual transmitted IV + is the result of the encryption, with whatever internal IV is used. + This method is explained in the TLS 1.1 RFC */ + if(ctx->negProtocolVersion >= TLS_Version_1_1 && + cipherType == blockCipherType) + { + payload.data -= blockSize; + } + + /* Update payload to reflect encrypted data: IV, contents, mac & padding */ + payload.length = payloadSize; + + + switch (cipherType) { + case blockCipherType: + /* Fill in the padding bytes & padding length field with the + * padding value; the protocol only requires the last byte, + * but filling them all in avoids leaking data */ + for (i = 1; i <= padding + 1; ++i) + payload.data[payload.length - i] = padding; + /* DROPTRHOUGH */ + case streamCipherType: + /* Encrypt the data */ + if ((err = cipher->encrypt(payload.data, + payload.data, payload.length, ctx->writeCipher.cipherCtx)) != 0) + goto fail; + break; + case aeadCipherType: + check(0); + break; + default: + check(0); + return errSSLRecordInternal; + } + + /* Enqueue the record to be written from the idle loop */ + if (ctx->recordWriteQueue == 0) + ctx->recordWriteQueue = out; + else + { queue = ctx->recordWriteQueue; + while (queue->next != 0) + queue = queue->next; + queue->next = out; + } + + /* Increment the sequence number */ + IncrementUInt64(&ctx->writeCipher.sequenceNum); + + return 0; + +fail: + /* + * Only for if we fail between when the WaitingRecord is allocated and when + * it is queued + */ + sslFree(out); + return err; +} + +static int ssl3DecryptRecord( + uint8_t type, + SSLBuffer *payload, + struct SSLRecordInternalContext *ctx) +{ + int err; + SSLBuffer content; + + CipherType cipherType = ctx->readCipher.symCipher->params->cipherType; + const Cipher *c = &ctx->readCipher.symCipher->c.cipher; + switch (cipherType) { + case blockCipherType: + if ((payload->length % ctx->readCipher.symCipher->params->blockSize) != 0) + { + return errSSLRecordDecryptionFail; + } + /* DROPTHROUGH */ + case streamCipherType: + /* Decrypt in place */ + err = c->decrypt(payload->data, payload->data, + payload->length, ctx->readCipher.cipherCtx); + break; + case aeadCipherType: + default: + check(0); + return errSSLRecordInternal; + } + if (err != 0) + { + return errSSLRecordDecryptionFail; + } + + /* Locate content within decrypted payload */ + content.data = payload->data; + content.length = payload->length - ctx->readCipher.macRef->hash->digestSize; + if (cipherType == blockCipherType) + { /* padding can't be equal to or more than a block */ + if (payload->data[payload->length - 1] >= ctx->readCipher.symCipher->params->blockSize) + { + sslErrorLog("DecryptSSLRecord: bad padding length (%d)\n", + (unsigned)payload->data[payload->length - 1]); + return errSSLRecordDecryptionFail; + } + content.length -= 1 + payload->data[payload->length - 1]; + /* Remove block size padding */ + } + + /* Verify MAC on payload */ + if (ctx->readCipher.macRef->hash->digestSize > 0) + /* Optimize away MAC for null case */ + if ((err = SSLVerifyMac(type, &content, + payload->data + content.length, ctx)) != 0) + { + return errSSLRecordBadRecordMac; + } + + *payload = content; /* Modify payload buffer to indicate content length */ + + return 0; +} + +/* initialize a per-CipherContext HashHmacContext for use in MACing each record */ +static int ssl3InitMac ( + CipherContext *cipherCtx) // macRef, macSecret valid on entry + // macCtx valid on return +{ + const HashReference *hash; + SSLBuffer *hashCtx; + int serr; + + check(cipherCtx->macRef != NULL); + hash = cipherCtx->macRef->hash; + check(hash != NULL); + + hashCtx = &cipherCtx->macCtx.hashCtx; + if(hashCtx->data != NULL) { + SSLFreeBuffer(hashCtx); + } + serr = SSLAllocBuffer(hashCtx, hash->contextSize); + if(serr) { + return serr; + } + return 0; +} + +static int ssl3FreeMac ( + CipherContext *cipherCtx) +{ + SSLBuffer *hashCtx; + + check(cipherCtx != NULL); + /* this can be called on a completely zeroed out CipherContext... */ + if(cipherCtx->macRef == NULL) { + return 0; + } + hashCtx = &cipherCtx->macCtx.hashCtx; + if(hashCtx->data != NULL) { + sslFree(hashCtx->data); + hashCtx->data = NULL; + } + hashCtx->length = 0; + return 0; +} + +static int ssl3ComputeMac ( + uint8_t type, + SSLBuffer data, + SSLBuffer mac, // caller mallocs data + CipherContext *cipherCtx, // assumes macCtx, macRef + sslUint64 seqNo, + struct SSLRecordInternalContext *ctx) +{ + int err; + uint8_t innerDigestData[SSL_MAX_DIGEST_LEN]; + uint8_t scratchData[11], *charPtr; + SSLBuffer digest, digestCtx, scratch; + SSLBuffer secret; + + const HashReference *hash; + + check(cipherCtx != NULL); + check(cipherCtx->macRef != NULL); + hash = cipherCtx->macRef->hash; + check(hash != NULL); + check(hash->macPadSize <= MAX_MAC_PADDING); + check(hash->digestSize <= SSL_MAX_DIGEST_LEN); + digestCtx = cipherCtx->macCtx.hashCtx; // may be NULL, for null cipher + secret.data = cipherCtx->macSecret; + secret.length = hash->digestSize; + + /* init'd early in SSLNewContext() */ + check(SSLMACPad1[0] == 0x36 && SSLMACPad2[0] == 0x5C); + + /* + * MAC = hash( MAC_write_secret + pad_2 + + * hash( MAC_write_secret + pad_1 + seq_num + type + + * length + content ) + * ) + */ + if ((err = hash->init(&digestCtx)) != 0) + goto exit; + if ((err = hash->update(&digestCtx, &secret)) != 0) /* MAC secret */ + goto exit; + scratch.data = (uint8_t *)SSLMACPad1; + scratch.length = hash->macPadSize; + if ((err = hash->update(&digestCtx, &scratch)) != 0) /* pad1 */ + goto exit; + charPtr = scratchData; + charPtr = SSLEncodeUInt64(charPtr, seqNo); + *charPtr++ = type; + charPtr = SSLEncodeSize(charPtr, data.length, 2); + scratch.data = scratchData; + scratch.length = 11; + check(charPtr = scratchData+11); + if ((err = hash->update(&digestCtx, &scratch)) != 0) + /* sequenceNo, type & length */ + goto exit; + if ((err = hash->update(&digestCtx, &data)) != 0) /* content */ + goto exit; + digest.data = innerDigestData; + digest.length = hash->digestSize; + if ((err = hash->final(&digestCtx, &digest)) != 0) /* figure inner digest */ + goto exit; + + if ((err = hash->init(&digestCtx)) != 0) + goto exit; + if ((err = hash->update(&digestCtx, &secret)) != 0) /* MAC secret */ + goto exit; + scratch.data = (uint8_t *)SSLMACPad2; + scratch.length = hash->macPadSize; + if ((err = hash->update(&digestCtx, &scratch)) != 0) /* pad2 */ + goto exit; + if ((err = hash->update(&digestCtx, &digest)) != 0) /* inner digest */ + goto exit; + if ((err = hash->final(&digestCtx, &mac)) != 0) /* figure the mac */ + goto exit; + + err = 0; /* redundant, I know */ + +exit: + return err; +} + + +const SslRecordCallouts Ssl3RecordCallouts = { + ssl3DecryptRecord, + ssl3WriteRecord, + ssl3InitMac, + ssl3FreeMac, + ssl3ComputeMac, +};