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authorLibravatar vnugent <public@vaughnnugent.com>2024-04-25 17:45:42 -0400
committerLibravatar vnugent <public@vaughnnugent.com>2024-04-25 17:45:42 -0400
commit6ff8bb11774c51fd341b7699a3938fd894995fbf (patch)
tree823ef4f5397e7ed96a5198a83d0c3b3145b3d127 /src/crypto/impl/bcrypt.c
parent7cb7a93de4f6f5e741bc5129e3d928e44f050930 (diff)
refactor: Finish support and testing for mbedtls
Diffstat (limited to 'src/crypto/impl/bcrypt.c')
-rw-r--r--src/crypto/impl/bcrypt.c86
1 files changed, 27 insertions, 59 deletions
diff --git a/src/crypto/impl/bcrypt.c b/src/crypto/impl/bcrypt.c
index 970f68f..9b01cac 100644
--- a/src/crypto/impl/bcrypt.c
+++ b/src/crypto/impl/bcrypt.c
@@ -32,8 +32,10 @@
#include <bcrypt.h>
#include "nc-util.h"
+#include "hkdf.h"
-#define IF_BC_FAIL(x) if(!BCRYPT_SUCCESS(x))
+#define IF_BC_FAIL(x) if(!BCRYPT_SUCCESS(x))
+#define BC_FAIL(x) if(!BCRYPT_SUCCESS(x)) return CSTATUS_FAIL;
struct _bcrypt_ctx
{
@@ -68,8 +70,8 @@ _IMPLSTB NTSTATUS _bcCreateHmac(struct _bcrypt_ctx* ctx, const cspan_t* key)
{
/*
* NOTE:
- * I am not explicitly managing the hash object buffer. By setting
- * the hash object to NULL, and length to 0, the buffer will be
+ * I am not explicitly managing the update object buffer. By setting
+ * the update object to NULL, and length to 0, the buffer will be
* managed by the bcrypt library.
*
* See: https://learn.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptcreatehash
@@ -113,7 +115,7 @@ _IMPLSTB NTSTATUS _bcFinishHash(const struct _bcrypt_ctx* ctx, sha256_t digestOu
_IMPLSTB void _bcDestroyCtx(struct _bcrypt_ctx* ctx)
{
- /* Free the hash memory if it was allocated */
+ /* Free the update memory if it was allocated */
if(ctx->hHash) BCryptDestroyHash(ctx->hHash);
/* Close the algorithm provider */
@@ -214,76 +216,42 @@ _IMPLSTB void _bcDestroyCtx(struct _bcrypt_ctx* ctx)
#define _IMPL_CRYPTO_SHA256_HKDF_EXPAND _bcrypt_fallback_hkdf_expand
- /* Include string for memmove */
- #include <string.h>
-
- static void ncWriteSpanS(span_t* span, uint32_t offset, const uint8_t* data, uint32_t size)
+ cstatus_t _bcrypt_hkdf_update(void* ctx, const cspan_t* data)
{
- DEBUG_ASSERT2(span != NULL, "Expected span to be non-null")
- DEBUG_ASSERT2(data != NULL, "Expected data to be non-null")
- DEBUG_ASSERT2(offset + size <= span->size, "Expected offset + size to be less than span size")
+ DEBUG_ASSERT(ctx != NULL)
- /* Copy data to span */
- memmove(span->data + offset, data, size);
+ BC_FAIL(_bcHashData((struct _bcrypt_ctx*)ctx, data))
+ return CSTATUS_OK;
}
- STATIC_ASSERT(HKDF_IN_BUF_SIZE > SHA256_DIGEST_SIZE, "HDK Buffer must be at least the size of the underlying hashing alg output")
-
- /*
- * The following functions implements the HKDF expand function using an existing
- * HMAC function. This is a fallback implementation for Windows platforms at the moment.
- *
- * This follows the guidence from RFC 5869: https://tools.ietf.org/html/rfc5869
- */
+ cstatus_t _bcrypt_hkdf_finish(void* ctx, sha256_t hmacOut32)
+ {
+ DEBUG_ASSERT(ctx != NULL)
- #define _BC_MIN(a, b) (a < b ? a : b)
+ BC_FAIL(_bcFinishHash((struct _bcrypt_ctx*)ctx, hmacOut32))
+ return CSTATUS_OK;
+ }
_IMPLSTB cstatus_t _bcrypt_fallback_hkdf_expand(const cspan_t* prk, const cspan_t* info, span_t* okm)
{
cstatus_t result;
struct _bcrypt_ctx ctx;
+ struct nc_hkdf_fn_cb_struct handler;
- uint8_t counter;
- uint32_t tLen, okmOffset;
- uint8_t t[HKDF_IN_BUF_SIZE];
-
- _IMPL_SECURE_ZERO_MEMSET(t, sizeof(t));
-
- tLen = 0; /* T(0) is an empty string(zero length) */
- okmOffset = 0;
- result = CSTATUS_FAIL; /* Start in fail state */
-
- /* Init context with hmac flag set, it will be reused */
- IF_BC_FAIL(_bcInitSha256(&ctx, BCRYPT_ALG_HANDLE_HMAC_FLAG)) goto Exit;
-
- /* Set hmac key to the prk, alg is set to reusable */
- IF_BC_FAIL(_bcCreateHmac(&ctx, prk)) goto Exit;
-
- /* Compute T(N) = HMAC(prk, T(n-1) | info | n) */
- for (counter = 1; okmOffset < okm->size; counter++)
- {
- IF_BC_FAIL(_bcHashDataRaw(&ctx, t, tLen)) goto Exit;
- IF_BC_FAIL(_bcHashData(&ctx, info)) goto Exit;
- IF_BC_FAIL(_bcHashDataRaw(&ctx, &counter, sizeof(counter))) goto Exit;
-
- /* Write current hash state to t buffer */
- IF_BC_FAIL(_bcFinishHash(&ctx, t)) goto Exit;
+ handler.update = _bcrypt_hkdf_update;
+ handler.finish = _bcrypt_hkdf_finish;
- /* Set the length of the current hash state */
- tLen = _BC_MIN(okm->size - okmOffset, SHA256_DIGEST_SIZE);
+ /* Init bcrypt */
+ BC_FAIL(_bcInitSha256(&ctx, BCRYPT_ALG_HANDLE_HMAC_FLAG))
- DEBUG_ASSERT(tLen <= sizeof(t));
+ BC_FAIL(_bcCreateHmac(&ctx, prk))
- /* write the T buffer back to okm */
- ncWriteSpanS(okm, okmOffset, t, tLen);
+ /*
+ * NOTE! Hmac reusable flag must be set to allow for multiple
+ * calls to the finish function without losing the context.
+ */
- /* shift base okm pointer by T */
- okmOffset += tLen;
- }
-
- result = CSTATUS_OK; /* HMAC operation completed, so set success */
-
- Exit:
+ result = hkdfExpandProcess(&handler, &ctx, info, okm);
_bcDestroyCtx(&ctx);