Source code

Revision control

Other Tools

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* SSL Primitives: Public HKDF and AEAD Functions
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "blapit.h"
#include "keyhi.h"
#include "pk11pub.h"
#include "sechash.h"
#include "ssl.h"
#include "sslexp.h"
#include "sslerr.h"
#include "sslproto.h"
#include "sslimpl.h"
#include "tls13con.h"
#include "tls13hkdf.h"
struct SSLAeadContextStr {
/* sigh, the API creates a single context, but then uses either encrypt
* and decrypt on that context. We should take an encrypt/decrypt
* variable here, but for now create two contexts. */
PK11Context *encryptContext;
PK11Context *decryptContext;
int tagLen;
int ivLen;
unsigned char iv[MAX_IV_LENGTH];
};
SECStatus
SSLExp_MakeVariantAead(PRUint16 version, PRUint16 cipherSuite, SSLProtocolVariant variant,
PK11SymKey *secret, const char *labelPrefix,
unsigned int labelPrefixLen, SSLAeadContext **ctx)
{
SSLAeadContext *out = NULL;
char label[255]; // Maximum length label.
static const char *const keySuffix = "key";
static const char *const ivSuffix = "iv";
CK_MECHANISM_TYPE mech;
SECItem nullParams = { siBuffer, NULL, 0 };
PK11SymKey *key = NULL;
PORT_Assert(strlen(keySuffix) >= strlen(ivSuffix));
if (secret == NULL || ctx == NULL ||
(labelPrefix == NULL && labelPrefixLen > 0) ||
labelPrefixLen + strlen(keySuffix) > sizeof(label)) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
goto loser;
}
SSLHashType hash;
const ssl3BulkCipherDef *cipher;
SECStatus rv = tls13_GetHashAndCipher(version, cipherSuite,
&hash, &cipher);
if (rv != SECSuccess) {
goto loser; /* Code already set. */
}
out = PORT_ZNew(SSLAeadContext);
if (out == NULL) {
goto loser;
}
mech = ssl3_Alg2Mech(cipher->calg);
out->ivLen = cipher->iv_size + cipher->explicit_nonce_size;
out->tagLen = cipher->tag_size;
memcpy(label, labelPrefix, labelPrefixLen);
memcpy(label + labelPrefixLen, ivSuffix, strlen(ivSuffix));
unsigned int labelLen = labelPrefixLen + strlen(ivSuffix);
unsigned int ivLen = cipher->iv_size + cipher->explicit_nonce_size;
rv = tls13_HkdfExpandLabelRaw(secret, hash,
NULL, 0, // Handshake hash.
label, labelLen, variant,
out->iv, ivLen);
if (rv != SECSuccess) {
goto loser;
}
memcpy(label + labelPrefixLen, keySuffix, strlen(keySuffix));
labelLen = labelPrefixLen + strlen(keySuffix);
rv = tls13_HkdfExpandLabel(secret, hash,
NULL, 0, // Handshake hash.
label, labelLen, mech, cipher->key_size,
variant, &key);
if (rv != SECSuccess) {
goto loser;
}
/* We really need to change the API to Create a context for each
* encrypt and decrypt rather than a single call that does both. it's
* almost certain that the underlying application tries to use the same
* context for both. */
out->encryptContext = PK11_CreateContextBySymKey(mech,
CKA_NSS_MESSAGE | CKA_ENCRYPT,
key, &nullParams);
if (out->encryptContext == NULL) {
goto loser;
}
out->decryptContext = PK11_CreateContextBySymKey(mech,
CKA_NSS_MESSAGE | CKA_DECRYPT,
key, &nullParams);
if (out->decryptContext == NULL) {
goto loser;
}
PK11_FreeSymKey(key);
*ctx = out;
return SECSuccess;
loser:
PK11_FreeSymKey(key);
SSLExp_DestroyAead(out);
return SECFailure;
}
SECStatus
SSLExp_MakeAead(PRUint16 version, PRUint16 cipherSuite, PK11SymKey *secret,
const char *labelPrefix, unsigned int labelPrefixLen, SSLAeadContext **ctx)
{
return SSLExp_MakeVariantAead(version, cipherSuite, ssl_variant_stream, secret,
labelPrefix, labelPrefixLen, ctx);
}
SECStatus
SSLExp_DestroyAead(SSLAeadContext *ctx)
{
if (!ctx) {
return SECSuccess;
}
if (ctx->encryptContext) {
PK11_DestroyContext(ctx->encryptContext, PR_TRUE);
}
if (ctx->decryptContext) {
PK11_DestroyContext(ctx->decryptContext, PR_TRUE);
}
PORT_ZFree(ctx, sizeof(*ctx));
return SECSuccess;
}
/* Bug 1529440 exists to refactor this and the other AEAD uses. */
static SECStatus
ssl_AeadInner(const SSLAeadContext *ctx, PK11Context *context,
PRBool decrypt, PRUint64 counter,
const PRUint8 *aad, unsigned int aadLen,
const PRUint8 *in, unsigned int inLen,
PRUint8 *out, unsigned int *outLen, unsigned int maxOut)
{
if (ctx == NULL || (aad == NULL && aadLen > 0) || in == NULL ||
out == NULL || outLen == NULL) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
// Setup the nonce.
PRUint8 nonce[sizeof(counter)] = { 0 };
sslBuffer nonceBuf = SSL_BUFFER_FIXED(nonce, sizeof(counter));
SECStatus rv = sslBuffer_AppendNumber(&nonceBuf, counter, sizeof(counter));
if (rv != SECSuccess) {
PORT_Assert(0);
return SECFailure;
}
/* at least on encrypt, we should not be using CKG_NO_GENERATE, but
* the current experimental API has the application tracking the counter
* rather than token. We should look at the QUIC code and see if the
* counter can be moved internally where it belongs. That would
* also get rid of the formatting code above and have the API
* call tls13_AEAD directly in SSLExp_Aead* */
return tls13_AEAD(context, decrypt, CKG_NO_GENERATE, 0, ctx->iv, NULL,
ctx->ivLen, nonce, sizeof(counter), aad, aadLen,
out, outLen, maxOut, ctx->tagLen, in, inLen);
}
SECStatus
SSLExp_AeadEncrypt(const SSLAeadContext *ctx, PRUint64 counter,
const PRUint8 *aad, unsigned int aadLen,
const PRUint8 *plaintext, unsigned int plaintextLen,
PRUint8 *out, unsigned int *outLen, unsigned int maxOut)
{
// false == encrypt
return ssl_AeadInner(ctx, ctx->encryptContext, PR_FALSE, counter,
aad, aadLen, plaintext, plaintextLen,
out, outLen, maxOut);
}
SECStatus
SSLExp_AeadDecrypt(const SSLAeadContext *ctx, PRUint64 counter,
const PRUint8 *aad, unsigned int aadLen,
const PRUint8 *ciphertext, unsigned int ciphertextLen,
PRUint8 *out, unsigned int *outLen, unsigned int maxOut)
{
// true == decrypt
return ssl_AeadInner(ctx, ctx->decryptContext, PR_TRUE, counter,
aad, aadLen, ciphertext, ciphertextLen,
out, outLen, maxOut);
}
SECStatus
SSLExp_HkdfExtract(PRUint16 version, PRUint16 cipherSuite,
PK11SymKey *salt, PK11SymKey *ikm, PK11SymKey **keyp)
{
if (keyp == NULL) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
SSLHashType hash;
SECStatus rv = tls13_GetHashAndCipher(version, cipherSuite,
&hash, NULL);
if (rv != SECSuccess) {
return SECFailure; /* Code already set. */
}
return tls13_HkdfExtract(salt, ikm, hash, keyp);
}
SECStatus
SSLExp_HkdfExpandLabel(PRUint16 version, PRUint16 cipherSuite, PK11SymKey *prk,
const PRUint8 *hsHash, unsigned int hsHashLen,
const char *label, unsigned int labelLen, PK11SymKey **keyp)
{
return SSLExp_HkdfVariantExpandLabel(version, cipherSuite, prk, hsHash, hsHashLen,
label, labelLen, ssl_variant_stream, keyp);
}
SECStatus
SSLExp_HkdfVariantExpandLabel(PRUint16 version, PRUint16 cipherSuite, PK11SymKey *prk,
const PRUint8 *hsHash, unsigned int hsHashLen,
const char *label, unsigned int labelLen,
SSLProtocolVariant variant, PK11SymKey **keyp)
{
if (prk == NULL || keyp == NULL ||
label == NULL || labelLen == 0) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
SSLHashType hash;
SECStatus rv = tls13_GetHashAndCipher(version, cipherSuite,
&hash, NULL);
if (rv != SECSuccess) {
return SECFailure; /* Code already set. */
}
return tls13_HkdfExpandLabel(prk, hash, hsHash, hsHashLen, label, labelLen,
CKM_HKDF_DERIVE,
tls13_GetHashSizeForHash(hash), variant, keyp);
}
SECStatus
SSLExp_HkdfExpandLabelWithMech(PRUint16 version, PRUint16 cipherSuite, PK11SymKey *prk,
const PRUint8 *hsHash, unsigned int hsHashLen,
const char *label, unsigned int labelLen,
CK_MECHANISM_TYPE mech, unsigned int keySize,
PK11SymKey **keyp)
{
return SSLExp_HkdfVariantExpandLabelWithMech(version, cipherSuite, prk, hsHash, hsHashLen,
label, labelLen, mech, keySize,
ssl_variant_stream, keyp);
}
SECStatus
SSLExp_HkdfVariantExpandLabelWithMech(PRUint16 version, PRUint16 cipherSuite, PK11SymKey *prk,
const PRUint8 *hsHash, unsigned int hsHashLen,
const char *label, unsigned int labelLen,
CK_MECHANISM_TYPE mech, unsigned int keySize,
SSLProtocolVariant variant, PK11SymKey **keyp)
{
if (prk == NULL || keyp == NULL ||
label == NULL || labelLen == 0 ||
mech == CKM_INVALID_MECHANISM || keySize == 0) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
SSLHashType hash;
SECStatus rv = tls13_GetHashAndCipher(version, cipherSuite,
&hash, NULL);
if (rv != SECSuccess) {
return SECFailure; /* Code already set. */
}
return tls13_HkdfExpandLabel(prk, hash, hsHash, hsHashLen, label, labelLen,
mech, keySize, variant, keyp);
}
SECStatus
ssl_CreateMaskingContextInner(PRUint16 version, PRUint16 cipherSuite,
SSLProtocolVariant variant,
PK11SymKey *secret,
const char *label,
unsigned int labelLen,
SSLMaskingContext **ctx)
{
if (!secret || !ctx || (!label && labelLen)) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
SSLMaskingContext *out = PORT_ZNew(SSLMaskingContext);
if (out == NULL) {
goto loser;
}
SSLHashType hash;
const ssl3BulkCipherDef *cipher;
SECStatus rv = tls13_GetHashAndCipher(version, cipherSuite,
&hash, &cipher);
if (rv != SECSuccess) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
goto loser; /* Code already set. */
}
out->mech = tls13_SequenceNumberEncryptionMechanism(cipher->calg);
if (out->mech == CKM_INVALID_MECHANISM) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
goto loser;
}
// Derive the masking key
rv = tls13_HkdfExpandLabel(secret, hash,
NULL, 0, // Handshake hash.
label, labelLen,
out->mech,
cipher->key_size, variant,
&out->secret);
if (rv != SECSuccess) {
goto loser;
}
out->version = version;
out->cipherSuite = cipherSuite;
*ctx = out;
return SECSuccess;
loser:
SSLExp_DestroyMaskingContext(out);
return SECFailure;
}
SECStatus
ssl_CreateMaskInner(SSLMaskingContext *ctx, const PRUint8 *sample,
unsigned int sampleLen, PRUint8 *outMask,
unsigned int maskLen)
{
if (!ctx || !sample || !sampleLen || !outMask || !maskLen) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (ctx->secret == NULL) {
PORT_SetError(SEC_ERROR_NO_KEY);
return SECFailure;
}
SECStatus rv = SECFailure;
unsigned int outMaskLen = 0;
int paramLen = 0;
/* Internal output len/buf, for use if the caller allocated and requested
* less than one block of output. |oneBlock| should have size equal to the
* largest block size supported below. */
PRUint8 oneBlock[AES_BLOCK_SIZE];
PRUint8 *outMask_ = outMask;
unsigned int maskLen_ = maskLen;
switch (ctx->mech) {
case CKM_AES_ECB:
if (sampleLen < AES_BLOCK_SIZE) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (maskLen_ < AES_BLOCK_SIZE) {
outMask_ = oneBlock;
maskLen_ = sizeof(oneBlock);
}
rv = PK11_Encrypt(ctx->secret,
ctx->mech,
NULL,
outMask_, &outMaskLen, maskLen_,
sample, AES_BLOCK_SIZE);
if (rv == SECSuccess &&
maskLen < AES_BLOCK_SIZE) {
memcpy(outMask, outMask_, maskLen);
}
break;
case CKM_NSS_CHACHA20_CTR:
paramLen = 16;
/* fall through */
case CKM_CHACHA20:
paramLen = (paramLen) ? paramLen : sizeof(CK_CHACHA20_PARAMS);
if (sampleLen < paramLen) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
SECItem param;
param.type = siBuffer;
param.len = paramLen;
param.data = (PRUint8 *)sample; // const-cast :(
unsigned char zeros[128] = { 0 };
if (maskLen > sizeof(zeros)) {
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
return SECFailure;
}
rv = PK11_Encrypt(ctx->secret,
ctx->mech,
&param,
outMask, &outMaskLen,
maskLen,
zeros, maskLen);
break;
default:
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (rv != SECSuccess) {
PORT_SetError(SEC_ERROR_PKCS11_FUNCTION_FAILED);
return SECFailure;
}
// Ensure we produced at least as much material as requested.
if (outMaskLen < maskLen) {
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
return SECFailure;
}
return SECSuccess;
}
SECStatus
ssl_DestroyMaskingContextInner(SSLMaskingContext *ctx)
{
if (!ctx) {
return SECSuccess;
}
PK11_FreeSymKey(ctx->secret);
PORT_ZFree(ctx, sizeof(*ctx));
return SECSuccess;
}
SECStatus
SSLExp_CreateMask(SSLMaskingContext *ctx, const PRUint8 *sample,
unsigned int sampleLen, PRUint8 *outMask,
unsigned int maskLen)
{
return ssl_CreateMaskInner(ctx, sample, sampleLen, outMask, maskLen);
}
SECStatus
SSLExp_CreateMaskingContext(PRUint16 version, PRUint16 cipherSuite,
PK11SymKey *secret,
const char *label,
unsigned int labelLen,
SSLMaskingContext **ctx)
{
return ssl_CreateMaskingContextInner(version, cipherSuite, ssl_variant_stream, secret,
label, labelLen, ctx);
}
SECStatus
SSLExp_CreateVariantMaskingContext(PRUint16 version, PRUint16 cipherSuite,
SSLProtocolVariant variant,
PK11SymKey *secret,
const char *label,
unsigned int labelLen,
SSLMaskingContext **ctx)
{
return ssl_CreateMaskingContextInner(version, cipherSuite, variant, secret,
label, labelLen, ctx);
}
SECStatus
SSLExp_DestroyMaskingContext(SSLMaskingContext *ctx)
{
return ssl_DestroyMaskingContextInner(ctx);
}