/
rsapkcs.c
1463 lines (1281 loc) · 41.8 KB
/
rsapkcs.c
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/* 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/. */
/*
* RSA PKCS#1 v2.1 (RFC 3447) operations
*/
#ifdef FREEBL_NO_DEPEND
#include "stubs.h"
#endif
#include "secerr.h"
#include "blapi.h"
#include "secitem.h"
#include "blapii.h"
#define RSA_BLOCK_MIN_PAD_LEN 8
#define RSA_BLOCK_FIRST_OCTET 0x00
#define RSA_BLOCK_PRIVATE_PAD_OCTET 0xff
#define RSA_BLOCK_AFTER_PAD_OCTET 0x00
/*
* RSA block types
*
* The values of RSA_BlockPrivate and RSA_BlockPublic are fixed.
* The value of RSA_BlockRaw isn't fixed by definition, but we are keeping
* the value that NSS has been using in the past.
*/
typedef enum {
RSA_BlockPrivate = 1, /* pad for a private-key operation */
RSA_BlockPublic = 2, /* pad for a public-key operation */
RSA_BlockRaw = 4 /* simply justify the block appropriately */
} RSA_BlockType;
/* Needed for RSA-PSS functions */
static const unsigned char eightZeros[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
/* Constant time comparison of a single byte.
* Returns 1 iff a == b, otherwise returns 0.
* Note: For ranges of bytes, use constantTimeCompare.
*/
static unsigned char
constantTimeEQ8(unsigned char a, unsigned char b)
{
unsigned char c = ~((a - b) | (b - a));
c >>= 7;
return c;
}
/* Constant time comparison of a range of bytes.
* Returns 1 iff len bytes of a are identical to len bytes of b, otherwise
* returns 0.
*/
static unsigned char
constantTimeCompare(const unsigned char *a,
const unsigned char *b,
unsigned int len)
{
unsigned char tmp = 0;
unsigned int i;
for (i = 0; i < len; ++i, ++a, ++b)
tmp |= *a ^ *b;
return constantTimeEQ8(0x00, tmp);
}
/* Constant time conditional.
* Returns a if c is 1, or b if c is 0. The result is undefined if c is
* not 0 or 1.
*/
static unsigned int
constantTimeCondition(unsigned int c,
unsigned int a,
unsigned int b)
{
return (~(c - 1) & a) | ((c - 1) & b);
}
static unsigned int
rsa_modulusLen(SECItem *modulus)
{
unsigned char byteZero = modulus->data[0];
unsigned int modLen = modulus->len - !byteZero;
return modLen;
}
static unsigned int
rsa_modulusBits(SECItem *modulus)
{
unsigned char byteZero = modulus->data[0];
unsigned int numBits = (modulus->len - 1) * 8;
if (byteZero == 0) {
numBits -= 8;
byteZero = modulus->data[1];
}
while (byteZero > 0) {
numBits++;
byteZero >>= 1;
}
return numBits;
}
/*
* Format one block of data for public/private key encryption using
* the rules defined in PKCS #1.
*/
static unsigned char *
rsa_FormatOneBlock(unsigned modulusLen,
RSA_BlockType blockType,
SECItem *data)
{
unsigned char *block;
unsigned char *bp;
int padLen;
int i, j;
SECStatus rv;
block = (unsigned char *)PORT_Alloc(modulusLen);
if (block == NULL)
return NULL;
bp = block;
/*
* All RSA blocks start with two octets:
* 0x00 || BlockType
*/
*bp++ = RSA_BLOCK_FIRST_OCTET;
*bp++ = (unsigned char)blockType;
switch (blockType) {
/*
* Blocks intended for private-key operation.
*/
case RSA_BlockPrivate: /* preferred method */
/*
* 0x00 || BT || Pad || 0x00 || ActualData
* 1 1 padLen 1 data->len
* Pad is either all 0x00 or all 0xff bytes, depending on blockType.
*/
padLen = modulusLen - data->len - 3;
PORT_Assert(padLen >= RSA_BLOCK_MIN_PAD_LEN);
if (padLen < RSA_BLOCK_MIN_PAD_LEN) {
PORT_Free(block);
return NULL;
}
PORT_Memset(bp, RSA_BLOCK_PRIVATE_PAD_OCTET, padLen);
bp += padLen;
*bp++ = RSA_BLOCK_AFTER_PAD_OCTET;
PORT_Memcpy(bp, data->data, data->len);
break;
/*
* Blocks intended for public-key operation.
*/
case RSA_BlockPublic:
/*
* 0x00 || BT || Pad || 0x00 || ActualData
* 1 1 padLen 1 data->len
* Pad is all non-zero random bytes.
*
* Build the block left to right.
* Fill the entire block from Pad to the end with random bytes.
* Use the bytes after Pad as a supply of extra random bytes from
* which to find replacements for the zero bytes in Pad.
* If we need more than that, refill the bytes after Pad with
* new random bytes as necessary.
*/
padLen = modulusLen - (data->len + 3);
PORT_Assert(padLen >= RSA_BLOCK_MIN_PAD_LEN);
if (padLen < RSA_BLOCK_MIN_PAD_LEN) {
PORT_Free(block);
return NULL;
}
j = modulusLen - 2;
rv = RNG_GenerateGlobalRandomBytes(bp, j);
if (rv == SECSuccess) {
for (i = 0; i < padLen;) {
unsigned char repl;
/* Pad with non-zero random data. */
if (bp[i] != RSA_BLOCK_AFTER_PAD_OCTET) {
++i;
continue;
}
if (j <= padLen) {
rv = RNG_GenerateGlobalRandomBytes(bp + padLen,
modulusLen - (2 + padLen));
if (rv != SECSuccess)
break;
j = modulusLen - 2;
}
do {
repl = bp[--j];
} while (repl == RSA_BLOCK_AFTER_PAD_OCTET && j > padLen);
if (repl != RSA_BLOCK_AFTER_PAD_OCTET) {
bp[i++] = repl;
}
}
}
if (rv != SECSuccess) {
PORT_Free(block);
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return NULL;
}
bp += padLen;
*bp++ = RSA_BLOCK_AFTER_PAD_OCTET;
PORT_Memcpy(bp, data->data, data->len);
break;
default:
PORT_Assert(0);
PORT_Free(block);
return NULL;
}
return block;
}
static SECStatus
rsa_FormatBlock(SECItem *result,
unsigned modulusLen,
RSA_BlockType blockType,
SECItem *data)
{
switch (blockType) {
case RSA_BlockPrivate:
case RSA_BlockPublic:
/*
* 0x00 || BT || Pad || 0x00 || ActualData
*
* The "3" below is the first octet + the second octet + the 0x00
* octet that always comes just before the ActualData.
*/
PORT_Assert(data->len <= (modulusLen - (3 + RSA_BLOCK_MIN_PAD_LEN)));
result->data = rsa_FormatOneBlock(modulusLen, blockType, data);
if (result->data == NULL) {
result->len = 0;
return SECFailure;
}
result->len = modulusLen;
break;
case RSA_BlockRaw:
/*
* Pad || ActualData
* Pad is zeros. The application is responsible for recovering
* the actual data.
*/
if (data->len > modulusLen) {
return SECFailure;
}
result->data = (unsigned char *)PORT_ZAlloc(modulusLen);
result->len = modulusLen;
PORT_Memcpy(result->data + (modulusLen - data->len),
data->data, data->len);
break;
default:
PORT_Assert(0);
result->data = NULL;
result->len = 0;
return SECFailure;
}
return SECSuccess;
}
/*
* Mask generation function MGF1 as defined in PKCS #1 v2.1 / RFC 3447.
*/
static SECStatus
MGF1(HASH_HashType hashAlg,
unsigned char *mask,
unsigned int maskLen,
const unsigned char *mgfSeed,
unsigned int mgfSeedLen)
{
unsigned int digestLen;
PRUint32 counter;
PRUint32 rounds;
unsigned char *tempHash;
unsigned char *temp;
const SECHashObject *hash;
void *hashContext;
unsigned char C[4];
SECStatus rv = SECSuccess;
hash = HASH_GetRawHashObject(hashAlg);
if (hash == NULL) {
return SECFailure;
}
hashContext = (*hash->create)();
rounds = (maskLen + hash->length - 1) / hash->length;
for (counter = 0; counter < rounds; counter++) {
C[0] = (unsigned char)((counter >> 24) & 0xff);
C[1] = (unsigned char)((counter >> 16) & 0xff);
C[2] = (unsigned char)((counter >> 8) & 0xff);
C[3] = (unsigned char)(counter & 0xff);
/* This could be optimized when the clone functions in
* rawhash.c are implemented. */
(*hash->begin)(hashContext);
(*hash->update)(hashContext, mgfSeed, mgfSeedLen);
(*hash->update)(hashContext, C, sizeof C);
tempHash = mask + counter * hash->length;
if (counter != (rounds - 1)) {
(*hash->end)(hashContext, tempHash, &digestLen, hash->length);
} else { /* we're in the last round and need to cut the hash */
temp = (unsigned char *)PORT_Alloc(hash->length);
if (!temp) {
rv = SECFailure;
goto done;
}
(*hash->end)(hashContext, temp, &digestLen, hash->length);
PORT_Memcpy(tempHash, temp, maskLen - counter * hash->length);
PORT_Free(temp);
}
}
done:
(*hash->destroy)(hashContext, PR_TRUE);
return rv;
}
/* XXX Doesn't set error code */
SECStatus
RSA_SignRaw(RSAPrivateKey *key,
unsigned char *output,
unsigned int *outputLen,
unsigned int maxOutputLen,
const unsigned char *data,
unsigned int dataLen)
{
SECStatus rv = SECSuccess;
unsigned int modulusLen = rsa_modulusLen(&key->modulus);
SECItem formatted;
SECItem unformatted;
if (maxOutputLen < modulusLen)
return SECFailure;
unformatted.len = dataLen;
unformatted.data = (unsigned char *)data;
formatted.data = NULL;
rv = rsa_FormatBlock(&formatted, modulusLen, RSA_BlockRaw, &unformatted);
if (rv != SECSuccess)
goto done;
rv = RSA_PrivateKeyOpDoubleChecked(key, output, formatted.data);
*outputLen = modulusLen;
done:
if (formatted.data != NULL)
PORT_ZFree(formatted.data, modulusLen);
return rv;
}
/* XXX Doesn't set error code */
SECStatus
RSA_CheckSignRaw(RSAPublicKey *key,
const unsigned char *sig,
unsigned int sigLen,
const unsigned char *hash,
unsigned int hashLen)
{
SECStatus rv;
unsigned int modulusLen = rsa_modulusLen(&key->modulus);
unsigned char *buffer;
if (sigLen != modulusLen)
goto failure;
if (hashLen > modulusLen)
goto failure;
buffer = (unsigned char *)PORT_Alloc(modulusLen + 1);
if (!buffer)
goto failure;
rv = RSA_PublicKeyOp(key, buffer, sig);
if (rv != SECSuccess)
goto loser;
/*
* make sure we get the same results
*/
/* XXX(rsleevi): Constant time */
/* NOTE: should we verify the leading zeros? */
if (PORT_Memcmp(buffer + (modulusLen - hashLen), hash, hashLen) != 0)
goto loser;
PORT_Free(buffer);
return SECSuccess;
loser:
PORT_Free(buffer);
failure:
return SECFailure;
}
/* XXX Doesn't set error code */
SECStatus
RSA_CheckSignRecoverRaw(RSAPublicKey *key,
unsigned char *data,
unsigned int *dataLen,
unsigned int maxDataLen,
const unsigned char *sig,
unsigned int sigLen)
{
SECStatus rv;
unsigned int modulusLen = rsa_modulusLen(&key->modulus);
if (sigLen != modulusLen)
goto failure;
if (maxDataLen < modulusLen)
goto failure;
rv = RSA_PublicKeyOp(key, data, sig);
if (rv != SECSuccess)
goto failure;
*dataLen = modulusLen;
return SECSuccess;
failure:
return SECFailure;
}
/* XXX Doesn't set error code */
SECStatus
RSA_EncryptRaw(RSAPublicKey *key,
unsigned char *output,
unsigned int *outputLen,
unsigned int maxOutputLen,
const unsigned char *input,
unsigned int inputLen)
{
SECStatus rv;
unsigned int modulusLen = rsa_modulusLen(&key->modulus);
SECItem formatted;
SECItem unformatted;
formatted.data = NULL;
if (maxOutputLen < modulusLen)
goto failure;
unformatted.len = inputLen;
unformatted.data = (unsigned char *)input;
formatted.data = NULL;
rv = rsa_FormatBlock(&formatted, modulusLen, RSA_BlockRaw, &unformatted);
if (rv != SECSuccess)
goto failure;
rv = RSA_PublicKeyOp(key, output, formatted.data);
if (rv != SECSuccess)
goto failure;
PORT_ZFree(formatted.data, modulusLen);
*outputLen = modulusLen;
return SECSuccess;
failure:
if (formatted.data != NULL)
PORT_ZFree(formatted.data, modulusLen);
return SECFailure;
}
/* XXX Doesn't set error code */
SECStatus
RSA_DecryptRaw(RSAPrivateKey *key,
unsigned char *output,
unsigned int *outputLen,
unsigned int maxOutputLen,
const unsigned char *input,
unsigned int inputLen)
{
SECStatus rv;
unsigned int modulusLen = rsa_modulusLen(&key->modulus);
if (modulusLen > maxOutputLen)
goto failure;
if (inputLen != modulusLen)
goto failure;
rv = RSA_PrivateKeyOp(key, output, input);
if (rv != SECSuccess)
goto failure;
*outputLen = modulusLen;
return SECSuccess;
failure:
return SECFailure;
}
/*
* Decodes an EME-OAEP encoded block, validating the encoding in constant
* time.
* Described in RFC 3447, section 7.1.2.
* input contains the encoded block, after decryption.
* label is the optional value L that was associated with the message.
* On success, the original message and message length will be stored in
* output and outputLen.
*/
static SECStatus
eme_oaep_decode(unsigned char *output,
unsigned int *outputLen,
unsigned int maxOutputLen,
const unsigned char *input,
unsigned int inputLen,
HASH_HashType hashAlg,
HASH_HashType maskHashAlg,
const unsigned char *label,
unsigned int labelLen)
{
const SECHashObject *hash;
void *hashContext;
SECStatus rv = SECFailure;
unsigned char labelHash[HASH_LENGTH_MAX];
unsigned int i;
unsigned int maskLen;
unsigned int paddingOffset;
unsigned char *mask = NULL;
unsigned char *tmpOutput = NULL;
unsigned char isGood;
unsigned char foundPaddingEnd;
hash = HASH_GetRawHashObject(hashAlg);
/* 1.c */
if (inputLen < (hash->length * 2) + 2) {
PORT_SetError(SEC_ERROR_INPUT_LEN);
return SECFailure;
}
/* Step 3.a - Generate lHash */
hashContext = (*hash->create)();
if (hashContext == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
return SECFailure;
}
(*hash->begin)(hashContext);
if (labelLen > 0)
(*hash->update)(hashContext, label, labelLen);
(*hash->end)(hashContext, labelHash, &i, sizeof(labelHash));
(*hash->destroy)(hashContext, PR_TRUE);
tmpOutput = (unsigned char *)PORT_Alloc(inputLen);
if (tmpOutput == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
goto done;
}
maskLen = inputLen - hash->length - 1;
mask = (unsigned char *)PORT_Alloc(maskLen);
if (mask == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
goto done;
}
PORT_Memcpy(tmpOutput, input, inputLen);
/* 3.c - Generate seedMask */
MGF1(maskHashAlg, mask, hash->length, &tmpOutput[1 + hash->length],
inputLen - hash->length - 1);
/* 3.d - Unmask seed */
for (i = 0; i < hash->length; ++i)
tmpOutput[1 + i] ^= mask[i];
/* 3.e - Generate dbMask */
MGF1(maskHashAlg, mask, maskLen, &tmpOutput[1], hash->length);
/* 3.f - Unmask DB */
for (i = 0; i < maskLen; ++i)
tmpOutput[1 + hash->length + i] ^= mask[i];
/* 3.g - Compare Y, lHash, and PS in constant time
* Warning: This code is timing dependent and must not disclose which of
* these were invalid.
*/
paddingOffset = 0;
isGood = 1;
foundPaddingEnd = 0;
/* Compare Y */
isGood &= constantTimeEQ8(0x00, tmpOutput[0]);
/* Compare lHash and lHash' */
isGood &= constantTimeCompare(&labelHash[0],
&tmpOutput[1 + hash->length],
hash->length);
/* Compare that the padding is zero or more zero octets, followed by a
* 0x01 octet */
for (i = 1 + (hash->length * 2); i < inputLen; ++i) {
unsigned char isZero = constantTimeEQ8(0x00, tmpOutput[i]);
unsigned char isOne = constantTimeEQ8(0x01, tmpOutput[i]);
/* non-constant time equivalent:
* if (tmpOutput[i] == 0x01 && !foundPaddingEnd)
* paddingOffset = i;
*/
paddingOffset = constantTimeCondition(isOne & ~foundPaddingEnd, i,
paddingOffset);
/* non-constant time equivalent:
* if (tmpOutput[i] == 0x01)
* foundPaddingEnd = true;
*
* Note: This may yield false positives, as it will be set whenever
* a 0x01 byte is encountered. If there was bad padding (eg:
* 0x03 0x02 0x01), foundPaddingEnd will still be set to true, and
* paddingOffset will still be set to 2.
*/
foundPaddingEnd = constantTimeCondition(isOne, 1, foundPaddingEnd);
/* non-constant time equivalent:
* if (tmpOutput[i] != 0x00 && tmpOutput[i] != 0x01 &&
* !foundPaddingEnd) {
* isGood = false;
* }
*
* Note: This may yield false positives, as a message (and padding)
* that is entirely zeros will result in isGood still being true. Thus
* it's necessary to check foundPaddingEnd is positive below.
*/
isGood = constantTimeCondition(~foundPaddingEnd & ~isZero, 0, isGood);
}
/* While both isGood and foundPaddingEnd may have false positives, they
* cannot BOTH have false positives. If both are not true, then an invalid
* message was received. Note, this comparison must still be done in constant
* time so as not to leak either condition.
*/
if (!(isGood & foundPaddingEnd)) {
PORT_SetError(SEC_ERROR_BAD_DATA);
goto done;
}
/* End timing dependent code */
++paddingOffset; /* Skip the 0x01 following the end of PS */
*outputLen = inputLen - paddingOffset;
if (*outputLen > maxOutputLen) {
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
goto done;
}
if (*outputLen)
PORT_Memcpy(output, &tmpOutput[paddingOffset], *outputLen);
rv = SECSuccess;
done:
if (mask)
PORT_ZFree(mask, maskLen);
if (tmpOutput)
PORT_ZFree(tmpOutput, inputLen);
return rv;
}
/*
* Generate an EME-OAEP encoded block for encryption
* Described in RFC 3447, section 7.1.1
* We use input instead of M for the message to be encrypted
* label is the optional value L to be associated with the message.
*/
static SECStatus
eme_oaep_encode(unsigned char *em,
unsigned int emLen,
const unsigned char *input,
unsigned int inputLen,
HASH_HashType hashAlg,
HASH_HashType maskHashAlg,
const unsigned char *label,
unsigned int labelLen,
const unsigned char *seed,
unsigned int seedLen)
{
const SECHashObject *hash;
void *hashContext;
SECStatus rv;
unsigned char *mask;
unsigned int reservedLen;
unsigned int dbMaskLen;
unsigned int i;
hash = HASH_GetRawHashObject(hashAlg);
PORT_Assert(seed == NULL || seedLen == hash->length);
/* Step 1.b */
reservedLen = (2 * hash->length) + 2;
if (emLen < reservedLen || inputLen > (emLen - reservedLen)) {
PORT_SetError(SEC_ERROR_INPUT_LEN);
return SECFailure;
}
/*
* From RFC 3447, Section 7.1
* +----------+---------+-------+
* DB = | lHash | PS | M |
* +----------+---------+-------+
* |
* +----------+ V
* | seed |--> MGF ---> xor
* +----------+ |
* | |
* +--+ V |
* |00| xor <----- MGF <-----|
* +--+ | |
* | | |
* V V V
* +--+----------+----------------------------+
* EM = |00|maskedSeed| maskedDB |
* +--+----------+----------------------------+
*
* We use mask to hold the result of the MGF functions, and all other
* values are generated in their final resting place.
*/
*em = 0x00;
/* Step 2.a - Generate lHash */
hashContext = (*hash->create)();
if (hashContext == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
return SECFailure;
}
(*hash->begin)(hashContext);
if (labelLen > 0)
(*hash->update)(hashContext, label, labelLen);
(*hash->end)(hashContext, &em[1 + hash->length], &i, hash->length);
(*hash->destroy)(hashContext, PR_TRUE);
/* Step 2.b - Generate PS */
if (emLen - reservedLen - inputLen > 0) {
PORT_Memset(em + 1 + (hash->length * 2), 0x00,
emLen - reservedLen - inputLen);
}
/* Step 2.c. - Generate DB
* DB = lHash || PS || 0x01 || M
* Note that PS and lHash have already been placed into em at their
* appropriate offsets. This just copies M into place
*/
em[emLen - inputLen - 1] = 0x01;
if (inputLen)
PORT_Memcpy(em + emLen - inputLen, input, inputLen);
if (seed == NULL) {
/* Step 2.d - Generate seed */
rv = RNG_GenerateGlobalRandomBytes(em + 1, hash->length);
if (rv != SECSuccess) {
return rv;
}
} else {
/* For Known Answer Tests, copy the supplied seed. */
PORT_Memcpy(em + 1, seed, seedLen);
}
/* Step 2.e - Generate dbMask*/
dbMaskLen = emLen - hash->length - 1;
mask = (unsigned char *)PORT_Alloc(dbMaskLen);
if (mask == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
return SECFailure;
}
MGF1(maskHashAlg, mask, dbMaskLen, em + 1, hash->length);
/* Step 2.f - Compute maskedDB*/
for (i = 0; i < dbMaskLen; ++i)
em[1 + hash->length + i] ^= mask[i];
/* Step 2.g - Generate seedMask */
MGF1(maskHashAlg, mask, hash->length, &em[1 + hash->length], dbMaskLen);
/* Step 2.h - Compute maskedSeed */
for (i = 0; i < hash->length; ++i)
em[1 + i] ^= mask[i];
PORT_ZFree(mask, dbMaskLen);
return SECSuccess;
}
SECStatus
RSA_EncryptOAEP(RSAPublicKey *key,
HASH_HashType hashAlg,
HASH_HashType maskHashAlg,
const unsigned char *label,
unsigned int labelLen,
const unsigned char *seed,
unsigned int seedLen,
unsigned char *output,
unsigned int *outputLen,
unsigned int maxOutputLen,
const unsigned char *input,
unsigned int inputLen)
{
SECStatus rv = SECFailure;
unsigned int modulusLen = rsa_modulusLen(&key->modulus);
unsigned char *oaepEncoded = NULL;
if (maxOutputLen < modulusLen) {
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
return SECFailure;
}
if ((hashAlg == HASH_AlgNULL) || (maskHashAlg == HASH_AlgNULL)) {
PORT_SetError(SEC_ERROR_INVALID_ALGORITHM);
return SECFailure;
}
if ((labelLen == 0 && label != NULL) ||
(labelLen > 0 && label == NULL)) {
PORT_SetError(SEC_ERROR_INVALID_ALGORITHM);
return SECFailure;
}
oaepEncoded = (unsigned char *)PORT_Alloc(modulusLen);
if (oaepEncoded == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
return SECFailure;
}
rv = eme_oaep_encode(oaepEncoded, modulusLen, input, inputLen,
hashAlg, maskHashAlg, label, labelLen, seed, seedLen);
if (rv != SECSuccess)
goto done;
rv = RSA_PublicKeyOp(key, output, oaepEncoded);
if (rv != SECSuccess)
goto done;
*outputLen = modulusLen;
done:
PORT_Free(oaepEncoded);
return rv;
}
SECStatus
RSA_DecryptOAEP(RSAPrivateKey *key,
HASH_HashType hashAlg,
HASH_HashType maskHashAlg,
const unsigned char *label,
unsigned int labelLen,
unsigned char *output,
unsigned int *outputLen,
unsigned int maxOutputLen,
const unsigned char *input,
unsigned int inputLen)
{
SECStatus rv = SECFailure;
unsigned int modulusLen = rsa_modulusLen(&key->modulus);
unsigned char *oaepEncoded = NULL;
if ((hashAlg == HASH_AlgNULL) || (maskHashAlg == HASH_AlgNULL)) {
PORT_SetError(SEC_ERROR_INVALID_ALGORITHM);
return SECFailure;
}
if (inputLen != modulusLen) {
PORT_SetError(SEC_ERROR_INPUT_LEN);
return SECFailure;
}
if ((labelLen == 0 && label != NULL) ||
(labelLen > 0 && label == NULL)) {
PORT_SetError(SEC_ERROR_INVALID_ALGORITHM);
return SECFailure;
}
oaepEncoded = (unsigned char *)PORT_Alloc(modulusLen);
if (oaepEncoded == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
return SECFailure;
}
rv = RSA_PrivateKeyOpDoubleChecked(key, oaepEncoded, input);
if (rv != SECSuccess) {
goto done;
}
rv = eme_oaep_decode(output, outputLen, maxOutputLen, oaepEncoded,
modulusLen, hashAlg, maskHashAlg, label,
labelLen);
done:
if (oaepEncoded)
PORT_ZFree(oaepEncoded, modulusLen);
return rv;
}
/* XXX Doesn't set error code */
SECStatus
RSA_EncryptBlock(RSAPublicKey *key,
unsigned char *output,
unsigned int *outputLen,
unsigned int maxOutputLen,
const unsigned char *input,
unsigned int inputLen)
{
SECStatus rv;
unsigned int modulusLen = rsa_modulusLen(&key->modulus);
SECItem formatted;
SECItem unformatted;
formatted.data = NULL;
if (maxOutputLen < modulusLen)
goto failure;
unformatted.len = inputLen;
unformatted.data = (unsigned char *)input;
formatted.data = NULL;
rv = rsa_FormatBlock(&formatted, modulusLen, RSA_BlockPublic,
&unformatted);
if (rv != SECSuccess)
goto failure;
rv = RSA_PublicKeyOp(key, output, formatted.data);
if (rv != SECSuccess)
goto failure;
PORT_ZFree(formatted.data, modulusLen);
*outputLen = modulusLen;
return SECSuccess;
failure:
if (formatted.data != NULL)
PORT_ZFree(formatted.data, modulusLen);
return SECFailure;
}
/* XXX Doesn't set error code */
SECStatus
RSA_DecryptBlock(RSAPrivateKey *key,
unsigned char *output,
unsigned int *outputLen,
unsigned int maxOutputLen,
const unsigned char *input,
unsigned int inputLen)
{
PRInt8 rv;
unsigned int modulusLen = rsa_modulusLen(&key->modulus);
unsigned int i;
unsigned char *buffer = NULL;
unsigned int outLen = 0;
unsigned int copyOutLen = modulusLen - 11;
if (inputLen != modulusLen || modulusLen < 10) {
return SECFailure;
}
if (copyOutLen > maxOutputLen) {
copyOutLen = maxOutputLen;
}
// Allocate enough space to decrypt + copyOutLen to allow copying outLen later.
buffer = PORT_ZAlloc(modulusLen + 1 + copyOutLen);
if (!buffer) {
return SECFailure;
}
// rv is 0 if everything is going well and 1 if an error occurs.
rv = RSA_PrivateKeyOp(key, buffer, input) != SECSuccess;
rv |= (buffer[0] != RSA_BLOCK_FIRST_OCTET) |
(buffer[1] != (unsigned char)RSA_BlockPublic);
// There have to be at least 8 bytes of padding.
for (i = 2; i < 10; i++) {
rv |= buffer[i] == RSA_BLOCK_AFTER_PAD_OCTET;
}
for (i = 10; i < modulusLen; i++) {
unsigned int newLen = modulusLen - i - 1;
unsigned int c = (buffer[i] == RSA_BLOCK_AFTER_PAD_OCTET) & (outLen == 0);
outLen = constantTimeCondition(c, newLen, outLen);
}
rv |= outLen == 0;
rv |= outLen > maxOutputLen;
// Note that output is set even if SECFailure is returned.
PORT_Memcpy(output, buffer + modulusLen - outLen, copyOutLen);
*outputLen = constantTimeCondition(outLen > maxOutputLen, maxOutputLen,
outLen);
PORT_Free(buffer);
for (i = 1; i < sizeof(rv) * 8; i <<= 1) {
rv |= rv << i;
}
return (SECStatus)rv;
}
/*
* Encode a RSA-PSS signature.
* Described in RFC 3447, section 9.1.1.
* We use mHash instead of M as input.
* emBits from the RFC is just modBits - 1, see section 8.1.1.
* We only support MGF1 as the MGF.
*/
static SECStatus