Improve wolfSSL_BN_rand.
- Previously, this function would round up the requested bits to the next multiple of 8. With this commit, the function returns a number of exactly the number of bits requested, which is the same behavior as OpenSSL. This problem was discovered by a user using the compatibility layer with OpenSSH's ssh-keygen utility. - This function now respects the top and bottom parameters. - Improved unit testing.
This commit is contained in:
Hayden Roche
parent
d531e21f34
commit
2077690bf0
119
src/ssl.c
119
src/ssl.c
@ -54552,75 +54552,72 @@ int wolfSSL_mask_bits(WOLFSSL_BIGNUM* bn, int n)
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/* WOLFSSL_SUCCESS on ok */
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int wolfSSL_BN_rand(WOLFSSL_BIGNUM* bn, int bits, int top, int bottom)
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{
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int ret = WOLFSSL_FAILURE;
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int len;
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int initTmpRng = 0;
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WC_RNG* rng = NULL;
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#ifdef WOLFSSL_SMALL_STACK
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WC_RNG* tmpRNG = NULL;
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byte* buff = NULL;
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#else
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WC_RNG tmpRNG[1];
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byte buff[1024];
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#endif
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int ret = WOLFSSL_SUCCESS;
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int len = (bits + 7) / 8;
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WC_RNG* rng = &globalRNG;
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byte* buff = NULL;
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(void)top;
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(void)bottom;
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WOLFSSL_MSG("wolfSSL_BN_rand");
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WOLFSSL_ENTER("wolfSSL_BN_rand");
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if (bits <= 0) {
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return WOLFSSL_FAILURE;
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if ((bn == NULL || bn->internal == NULL) || bits < 0 ||
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(bits == 0 && (bottom != 0 || top != -1)) || (bits == 1 && top > 0)) {
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WOLFSSL_MSG("Bad argument");
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ret = WOLFSSL_FAILURE;
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}
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len = bits / 8;
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if (bits % 8)
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len++;
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/* has to be a length of at least 1 since we set buf[0] and buf[len-1] */
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if (len < 1) {
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return WOLFSSL_FAILURE;
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}
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#ifdef WOLFSSL_SMALL_STACK
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buff = (byte*)XMALLOC(1024, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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tmpRNG = (WC_RNG*) XMALLOC(sizeof(WC_RNG), NULL, DYNAMIC_TYPE_RNG);
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if (buff == NULL || tmpRNG == NULL) {
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XFREE(buff, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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XFREE(tmpRNG, NULL, DYNAMIC_TYPE_RNG);
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return ret;
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}
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#endif
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if (bn == NULL || bn->internal == NULL)
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WOLFSSL_MSG("Bad function arguments");
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else if (wc_InitRng(tmpRNG) == 0) {
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rng = tmpRNG;
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initTmpRng = 1;
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}
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else if (initGlobalRNG)
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rng = &globalRNG;
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if (rng) {
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if (wc_RNG_GenerateBlock(rng, buff, len) != 0)
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WOLFSSL_MSG("Bad wc_RNG_GenerateBlock");
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else {
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buff[0] |= 0x80 | 0x40;
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buff[len-1] |= 0x01;
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if (mp_read_unsigned_bin((mp_int*)bn->internal,buff,len) != MP_OKAY)
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WOLFSSL_MSG("mp read bin failed");
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else
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ret = WOLFSSL_SUCCESS;
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if (ret == WOLFSSL_SUCCESS) {
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buff = (byte*)XMALLOC(len, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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if (buff == NULL) {
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WOLFSSL_MSG("Failed to allocate buffer.");
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XFREE(buff, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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ret = WOLFSSL_FAILURE;
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}
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}
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if (initTmpRng)
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wc_FreeRng(tmpRNG);
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if (ret == WOLFSSL_SUCCESS && initGlobalRNG == 0 &&
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wolfSSL_RAND_Init() != WOLFSSL_SUCCESS) {
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WOLFSSL_MSG("Failed to use global RNG.");
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ret = WOLFSSL_FAILURE;
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}
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#ifdef WOLFSSL_SMALL_STACK
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XFREE(buff, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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XFREE(tmpRNG, NULL, DYNAMIC_TYPE_RNG);
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#endif
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if (ret == WOLFSSL_SUCCESS && wc_RNG_GenerateBlock(rng, buff, len) != 0) {
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WOLFSSL_MSG("wc_RNG_GenerateBlock failed");
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ret = WOLFSSL_FAILURE;
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}
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if (ret == WOLFSSL_SUCCESS &&
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mp_read_unsigned_bin((mp_int*)bn->internal,buff,len) != MP_OKAY) {
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WOLFSSL_MSG("mp_read_unsigned_bin failed");
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ret = WOLFSSL_FAILURE;
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}
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if (ret == WOLFSSL_SUCCESS) {
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/* Truncate to requested bit length. */
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mp_rshb((mp_int*)bn->internal, 8 - (bits % 8));
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if (top == 0) {
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if (mp_set_bit((mp_int*)bn->internal, bits - 1) != MP_OKAY) {
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WOLFSSL_MSG("Failed to set top bit");
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ret = WOLFSSL_FAILURE;
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}
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}
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else if (top > 0) {
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if (mp_set_bit((mp_int*)bn->internal, bits - 1) != MP_OKAY ||
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mp_set_bit((mp_int*)bn->internal, bits - 2) != MP_OKAY) {
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WOLFSSL_MSG("Failed to set top 2 bits");
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ret = WOLFSSL_FAILURE;
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}
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}
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}
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if (ret == WOLFSSL_SUCCESS && bottom &&
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mp_set_bit((mp_int*)bn->internal, 0) != MP_OKAY) {
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WOLFSSL_MSG("Failed to set 0th bit");
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ret = WOLFSSL_FAILURE;
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}
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if (buff != NULL) {
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XFREE(buff, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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}
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WOLFSSL_LEAVE("wolfSSL_BN_rand", ret);
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return ret;
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}
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44
tests/api.c
44
tests/api.c
@ -36938,25 +36938,49 @@ static void test_wolfSSL_RAND_bytes(void)
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static void test_wolfSSL_BN_rand(void)
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{
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#if defined(OPENSSL_EXTRA)
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#if defined(OPENSSL_EXTRA)
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BIGNUM* bn;
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BIGNUM* range;
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printf(testingFmt, "wolfSSL_BN_rand()");
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/* Error conditions. */
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/* NULL BN. */
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AssertIntEQ(BN_rand(NULL, 0, 0, 0), SSL_FAILURE);
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AssertNotNull(bn = BN_new());
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AssertIntNE(BN_rand(bn, 0, 0, 0), SSL_SUCCESS);
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BN_free(bn);
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/* Negative bits. */
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AssertIntEQ(BN_rand(bn, -2, 0, 0), SSL_FAILURE);
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/* 0 bits and top is not -1. */
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AssertIntEQ(BN_rand(bn, 0, 1, 0), SSL_FAILURE);
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/* 0 bits and bottom is not 0. */
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AssertIntEQ(BN_rand(bn, 0, 0, 1), SSL_FAILURE);
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/* 1 bit and top is 1. */
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AssertIntEQ(BN_rand(bn, 1, 1, 0), SSL_FAILURE);
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AssertIntEQ(BN_rand(bn, 0, -1, 0), SSL_SUCCESS);
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AssertIntEQ(BN_num_bits(bn), 0);
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AssertNotNull(bn = BN_new());
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AssertIntEQ(BN_rand(bn, 8, 0, 0), SSL_SUCCESS);
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BN_free(bn);
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AssertIntEQ(BN_num_bits(bn), 8);
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/* When top is 0, top bit should be 1. */
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AssertIntEQ(BN_is_bit_set(bn, 7), SSL_SUCCESS);
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AssertNotNull(bn = BN_new());
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AssertIntEQ(BN_rand(bn, 64, 0, 0), SSL_SUCCESS);
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BN_free(bn);
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AssertIntEQ(BN_rand(bn, 8, 1, 0), SSL_SUCCESS);
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/* When top is 1, top 2 bits should be 1. */
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AssertIntEQ(BN_is_bit_set(bn, 7), SSL_SUCCESS);
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AssertIntEQ(BN_is_bit_set(bn, 6), SSL_SUCCESS);
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AssertIntEQ(BN_rand(bn, 8, 0, 1), SSL_SUCCESS);
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/* When bottom is 1, bottom bit should be 1. */
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AssertIntEQ(BN_is_bit_set(bn, 0), SSL_SUCCESS);
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/* Regression test: Older versions of wolfSSL_BN_rand would round the
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* requested number of bits up to the nearest multiple of 8. E.g. in this
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* case, requesting a 13-bit random number would actually return a 16-bit
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* random number. */
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AssertIntEQ(BN_rand(bn, 13, 0, 0), SSL_SUCCESS);
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AssertIntEQ(BN_num_bits(bn), 13);
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AssertNotNull(bn = BN_new());
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AssertNotNull(range = BN_new());
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AssertIntEQ(BN_rand(range, 64, 0, 0), SSL_SUCCESS);
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AssertIntEQ(BN_rand_range(bn, range), SSL_SUCCESS);
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@ -36964,7 +36988,7 @@ static void test_wolfSSL_BN_rand(void)
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BN_free(range);
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printf(resultFmt, passed);
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#endif
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#endif
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}
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static void test_wolfSSL_pseudo_rand(void)
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