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authorLibravatar vnugent <public@vaughnnugent.com>2024-04-23 18:19:31 -0400
committerLibravatar vnugent <public@vaughnnugent.com>2024-04-23 18:19:31 -0400
commit7cb7a93de4f6f5e741bc5129e3d928e44f050930 (patch)
treeae5c564a0c3c60d0b4dac13ac8e8e3ebf7906ab1 /src/crypto/nc-crypto.c
parent30e8dda6cbea86bdee6d5dfe48514385d3b9f81b (diff)
refactor!: MbedTLS on Windows, switch to uint32
Diffstat (limited to 'src/crypto/nc-crypto.c')
-rw-r--r--src/crypto/nc-crypto.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/src/crypto/nc-crypto.c b/src/crypto/nc-crypto.c
new file mode 100644
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--- /dev/null
+++ b/src/crypto/nc-crypto.c
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+/*
+* Copyright (c) 2024 Vaughn Nugent
+*
+* Package: noscrypt
+* File: nc-crypto.c
+*
+* This library is free software; you can redistribute it and/or
+* modify it under the terms of the GNU Lesser General Public License
+* as published by the Free Software Foundation; either version 2.1
+* of the License, or (at your option) any later version.
+*
+* This library is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+* Lesser General Public License for more details.
+*
+* You should have received a copy of the GNU Lesser General Public License
+* along with noscrypt. If not, see http://www.gnu.org/licenses/.
+*/
+
+#include "nc-util.h"
+#include "nc-crypto.h"
+
+/*
+* Functions are not forced inline, just suggested.
+* So unless it beomes a performance issue, I will leave
+* most/all impl functions inline and let the compiler
+* decide.
+*/
+
+#define _IMPLSTB static _nc_fn_inline
+
+/*
+* Impl .c files may define the following macros for function implementations:
+*
+* _IMPL_SECURE_ZERO_MEMSET secure memset 0 function
+* _IMPL_CHACHA20_CRYPT chacha20 cipher function
+* _IMPL_CRYPTO_FIXED_TIME_COMPARE fixed time compare function
+* _IMPL_CRYPTO_SHA256_HMAC sha256 hmac function
+* _IMPL_CRYPTO_SHA256_DIGEST standard sha256 digest function
+* _IMPL_CRYPTO_SHA256_HKDF_EXPAND hkdf expand function
+* _IMPL_CRYPTO_SHA256_HKDF_EXTRACT hkdf extract function
+*
+* Macros are used to allow the preprocessor to select the correct implementation
+* or raise errors if no implementation is defined.
+*/
+
+
+
+/*
+* Prioritize embedded builds with mbedtls
+*/
+#include "impl/mbedtls.c"
+
+/*
+* Include openssl as an alternative default
+* implementation
+*/
+#include "impl/openssl.c"
+
+/*
+* Include win32 platform specific fallback support
+* using bcrypt.
+*/
+#include "impl/bcrypt.c"
+
+/*
+* Handle default implementations of secure
+* memset 0 functions for each platform.
+*/
+#ifndef _IMPL_SECURE_ZERO_MEMSET
+ #if defined(__GNUC__)
+ /*
+ * When using libc, we can use explicit_bzero
+ * as secure memset implementation.
+ *
+ * https://sourceware.org/glibc/manual/2.39/html_mono/libc.html#Erasing-Sensitive-Data
+ */
+ #include <string.h>
+ #define _IMPL_SECURE_ZERO_MEMSET explicit_bzero
+ #endif
+#endif
+
+/*
+* Finally fall back to monocipher to handle some
+* that are not provided by other libraries.
+*
+* Platform specific opimizations are considered
+* "better" than monocypher options, so this is
+* added as a last resort. Momocypher is "correct"
+* and portable, but not optimized for any specific
+* platform.
+*/
+#include "impl/monocypher.c"
+
+
+#ifdef _IMPL_CRYPTO_SHA256_HMAC
+
+ /*
+ * If a library does not provide a HKDF extract function,
+ * we can just use the HMAC function as a fallback.
+ *
+ * This is a fallback because another library may provide
+ * a more optimized implementation.
+ */
+
+ #ifndef _IMPL_CRYPTO_SHA256_HKDF_EXTRACT
+
+ #define _IMPL_CRYPTO_SHA256_HKDF_EXTRACT _fallbackHkdfExtract
+
+ _IMPLSTB cstatus_t _fallbackHkdfExtract(const cspan_t* salt, const cspan_t* ikm, sha256_t prk)
+ {
+ return _IMPL_CRYPTO_SHA256_HMAC(salt, ikm, prk);
+ }
+
+ #endif /* !_IMPL_CRYPTO_SHA256_HKDF_EXTRACT */
+
+#endif /* _IMPL_CRYPTO_SHA256_HMAC */
+
+/* Fallback for fixed time comparison for all platforms */
+#ifndef _IMPL_CRYPTO_FIXED_TIME_COMPARE
+
+ #pragma message("Warning: No fixed time compare implementation defined, using fallback. This may not be secure on all platforms")
+
+ #define _IMPL_CRYPTO_FIXED_TIME_COMPARE _fallbackFixedTimeCompare
+
+ /*
+ * This implemntation is a slightly simplified version of
+ * MBed TLS constant time memcmp function, knowm to be a 32bit
+ * integer size
+ */
+
+ static uint32_t _fallbackFixedTimeCompare(const uint8_t* a, const uint8_t* b, uint32_t size)
+ {
+ size_t i;
+ uint32_t result;
+ uint8_t O;
+ volatile const uint8_t* A, * B;
+
+ result = 0;
+ O = 0;
+ A = (volatile const uint8_t*)a;
+ B = (volatile const uint8_t*)b;
+
+ /* Compare each byte */
+ for(i = 0; i < size; i++)
+ {
+ /* Handle volatile read */
+ O |= (A[i] ^ B[i]);
+
+ result |= O;
+ }
+
+ return result;
+ }
+
+#endif /* !_IMPL_CRYPTO_FIXED_TIME_COMPARE */
+
+
+/*
+* Internal function implementations that perform
+* basic checking and call the correct implementation
+* for the desired crypto impl.
+*/
+
+void ncCryptoSecureZero(void* ptr, uint32_t size)
+{
+ DEBUG_ASSERT2(ptr != NULL, "Expected ptr to be non-null")
+
+#ifndef _IMPL_SECURE_ZERO_MEMSET
+ #error "No secure memset implementation defined"
+#endif /* _IMPL_SECURE_ZERO_MEMSET */
+
+ _IMPL_SECURE_ZERO_MEMSET(ptr, size);
+}
+
+uint32_t ncCryptoFixedTimeComp(const uint8_t* a, const uint8_t* b, uint32_t size)
+{
+ DEBUG_ASSERT2(a != NULL, "Expected a to be non-null")
+ DEBUG_ASSERT2(b != NULL, "Expected b to be non-null")
+
+#ifndef _IMPL_CRYPTO_FIXED_TIME_COMPARE
+ #error "No fixed time compare implementation defined"
+#endif /* !_IMPL_CRYPTO_FIXED_TIME_COMPARE */
+
+ return _IMPL_CRYPTO_FIXED_TIME_COMPARE(a, b, size);
+}
+
+cstatus_t ncCryptoDigestSha256(const cspan_t* data, sha256_t digestOut32)
+{
+ /* Debug arg validate */
+ DEBUG_ASSERT2(data != NULL && data->data != NULL, "Expected data to be non-null")
+ DEBUG_ASSERT2(digestOut32 != NULL, "Expected digestOut32 to be non-null")
+
+#ifndef _IMPL_CRYPTO_SHA256_DIGEST
+ #error "No SHA256 implementation defined"
+#endif /* !_IMPL_CRYPTO_SHA256_DIGEST */
+
+ return _IMPL_CRYPTO_SHA256_DIGEST(data, digestOut32);
+}
+
+cstatus_t ncCryptoHmacSha256(const cspan_t* key, const cspan_t* data, sha256_t hmacOut32)
+{
+ /* Debug arg validate */
+ DEBUG_ASSERT2(key != NULL && key->data != NULL, "Expected key to be non-null")
+ DEBUG_ASSERT2(data != NULL && data->data != NULL, "Expected data to be non-null")
+ DEBUG_ASSERT2(hmacOut32 != NULL && data->data != NULL, "Expected hmacOut32 to be non-null")
+
+#ifndef _IMPL_CRYPTO_SHA256_HMAC
+ #error "No SHA256 HMAC implementation defined"
+#endif /* !_IMPL_CRYPTO_SHA256_HMAC */
+
+ return _IMPL_CRYPTO_SHA256_HMAC(key, data, hmacOut32);
+}
+
+cstatus_t ncCryptoSha256HkdfExpand(const cspan_t* prk, const cspan_t* info, span_t* okm)
+{
+ /* Debug arg validate */
+ DEBUG_ASSERT2(prk != NULL && prk->data != NULL, "Expected prk to be non-null")
+ DEBUG_ASSERT2(info != NULL && info->data != NULL, "Expected info to be non-null")
+ DEBUG_ASSERT2(okm != NULL && okm->data != NULL, "Expected okm to be non-null")
+
+ /*
+ * RFC 5869: 2.3
+ * "length of output keying material in octets (<= 255 * HashLen)"
+ */
+
+ if(okm->size > (uint32_t)(0xFFu * SHA256_DIGEST_SIZE))
+ {
+ return CSTATUS_FAIL;
+ }
+
+#ifndef _IMPL_CRYPTO_SHA256_HKDF_EXPAND
+ #error "No SHA256 HKDF expand implementation defined"
+#endif /* !_IMPL_CRYPTO_SHA256_HKDF_EXPAND */
+
+ return _IMPL_CRYPTO_SHA256_HKDF_EXPAND(prk, info, okm);
+}
+
+cstatus_t ncCryptoSha256HkdfExtract(const cspan_t* salt, const cspan_t* ikm, sha256_t prk)
+{
+ /* Debug arg validate */
+ DEBUG_ASSERT2(salt != NULL, "Expected salt to be non-null")
+ DEBUG_ASSERT2(ikm != NULL, "Expected ikm to be non-null")
+ DEBUG_ASSERT2(prk != NULL, "Expected prk to be non-null")
+
+#ifndef _IMPL_CRYPTO_SHA256_HKDF_EXTRACT
+ #error "No SHA256 HKDF extract implementation defined"
+#endif /* !_IMPL_CRYPTO_SHA256_HKDF_EXTRACT */
+
+ return _IMPL_CRYPTO_SHA256_HKDF_EXTRACT(salt, ikm, prk);
+}
+
+cstatus_t ncCryptoChacha20(
+ const uint8_t key[CHACHA_KEY_SIZE],
+ const uint8_t nonce[CHACHA_NONCE_SIZE],
+ const uint8_t* input,
+ uint8_t* output,
+ uint32_t dataSize
+)
+{
+ DEBUG_ASSERT2(key != NULL, "Expected key to be non-null")
+ DEBUG_ASSERT2(nonce != NULL, "Expected nonce to be non-null")
+ DEBUG_ASSERT2(input != NULL, "Expected input to be non-null")
+ DEBUG_ASSERT2(output != NULL, "Expected output to be non-null")
+
+#ifndef _IMPL_CHACHA20_CRYPT
+ #error "No chacha20 implementation defined"
+#endif /* !_IMPL_CHACHA20_CRYPT */
+
+ return _IMPL_CHACHA20_CRYPT(key, nonce, input, output, dataSize);
+}