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openssl: Add support for new API to squeeze data from XOFs

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This new API doesn't require a temporary buffer and generating a lot
of already consumed output.
This commit is contained in:
Tobias Brunner
2024-10-25 14:28:40 +02:00
parent bee06c9ec5
commit 3d0f6958a9
1 changed files with 30 additions and 5 deletions
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src/libstrongswan/plugins/openssl/openssl_xof.c
+30 -5
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@@ -1,5 +1,5 @@
/* /*
* Copyright (C) 2020 Tobias Brunner * Copyright (C) 2020-2023 Tobias Brunner
* *
* Copyright (C) secunet Security Networks AG * Copyright (C) secunet Security Networks AG
* *
@@ -50,6 +50,7 @@ struct private_xof_t {
*/ */
EVP_MD_CTX *ctx; EVP_MD_CTX *ctx;
#if OPENSSL_VERSION_NUMBER < 0x30300000L
/** /**
* Current seed * Current seed
*/ */
@@ -59,6 +60,7 @@ struct private_xof_t {
* Offset into generated data * Offset into generated data
*/ */
size_t offset; size_t offset;
#endif
}; };
METHOD(xof_t, get_type, ext_out_function_t, METHOD(xof_t, get_type, ext_out_function_t,
@@ -67,17 +69,33 @@ METHOD(xof_t, get_type, ext_out_function_t,
return this->algorithm; return this->algorithm;
} }
/**
* Initialize the EVP_MD_CTX with the given seed
*/
static bool init_md(private_xof_t *this, chunk_t seed)
{
return EVP_DigestInit_ex(this->ctx, this->md, NULL) == 1 &&
EVP_DigestUpdate(this->ctx, seed.ptr, seed.len) == 1;
}
METHOD(xof_t, get_bytes, bool, METHOD(xof_t, get_bytes, bool,
private_xof_t *this, size_t out_len, uint8_t *buffer) private_xof_t *this, size_t out_len, uint8_t *buffer)
{ {
bool success = FALSE; bool success = FALSE;
chunk_t data;
#if OPENSSL_VERSION_NUMBER >= 0x30300000L
/* this API is available since 3.2.0 */
if (EVP_DigestSqueeze(this->ctx, buffer, out_len) == 1)
{
success = TRUE;
}
#else /* OPENSSL_VERSION_NUMBER */
/* we can call EVP_DigestFinalXOF() only once, so to support an arbitrary /* we can call EVP_DigestFinalXOF() only once, so to support an arbitrary
* number of calls to get_bytes(), we request all the data we already * number of calls to get_bytes(), we request all the data we already
* requested previously and just ignore what we already handed out */ * requested previously and just ignore what we already handed out */
if (EVP_DigestInit_ex(this->ctx, this->md, NULL) == 1 && chunk_t data;
EVP_DigestUpdate(this->ctx, this->seed.ptr, this->seed.len) == 1)
if (init_md(this, this->seed))
{ {
data = chunk_alloc(out_len + this->offset); data = chunk_alloc(out_len + this->offset);
if (EVP_DigestFinalXOF(this->ctx, data.ptr, data.len) == 1) if (EVP_DigestFinalXOF(this->ctx, data.ptr, data.len) == 1)
@@ -88,6 +106,7 @@ METHOD(xof_t, get_bytes, bool,
} }
chunk_clear(&data); chunk_clear(&data);
} }
#endif /* OPENSSL_VERSION_NUMBER */
return success; return success;
} }
@@ -113,17 +132,23 @@ METHOD(xof_t, get_seed_size, size_t,
METHOD(xof_t, set_seed, bool, METHOD(xof_t, set_seed, bool,
private_xof_t *this, chunk_t seed) private_xof_t *this, chunk_t seed)
{ {
#if OPENSSL_VERSION_NUMBER >= 0x30300000L
return init_md(this, seed);
#else
chunk_clear(&this->seed); chunk_clear(&this->seed);
this->seed = chunk_clone(seed); this->seed = chunk_clone(seed);
this->offset = 0; this->offset = 0;
return TRUE; return TRUE;
#endif
} }
METHOD(xof_t, destroy, void, METHOD(xof_t, destroy, void,
private_xof_t *this) private_xof_t *this)
{ {
EVP_MD_CTX_free(this->ctx); #if OPENSSL_VERSION_NUMBER < 0x30300000L
chunk_clear(&this->seed); chunk_clear(&this->seed);
#endif
EVP_MD_CTX_free(this->ctx);
free(this); free(this);
} }