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Use OpenSSL 3 EVP_Q_mac for HMAC operations #196

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Merged
TheStormN merged 1 commit into from
Sep 13, 2026
Merged

Use OpenSSL 3 EVP_Q_mac for HMAC operations #196

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2 changes: 1 addition & 1 deletion src/include/jwk_int.h
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Original file line number Diff line number Diff line change
Expand Up @@ -88,7 +88,7 @@ bool cjose_jwk_hkdf(const EVP_MD *md,
const uint8_t *ikm,
size_t ikm_len,
uint8_t *okm,
unsigned int okm_len,
size_t okm_len,
cjose_err *err);

#endif // SRC_JWK_INT_H
15 changes: 8 additions & 7 deletions src/jwe.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,6 @@
#include <openssl/rsa.h>
#include <openssl/evp.h>
#include <openssl/aes.h>
#include <openssl/hmac.h>

#include "include/concatkdf_int.h"
#include "include/header_int.h"
Expand Down Expand Up @@ -2141,7 +2140,7 @@ static bool _cjose_jwe_encrypt_dat_aes_gcm(cjose_jwe_t *jwe, const uint8_t *plai
}

////////////////////////////////////////////////////////////////////////////////
static bool _cjose_jwe_calc_auth_tag(const char *enc, cjose_jwe_t *jwe, uint8_t *md, unsigned int *md_len, cjose_err *err)
static bool _cjose_jwe_calc_auth_tag(const char *enc, cjose_jwe_t *jwe, uint8_t *md, size_t *md_len, cjose_err *err)
{
bool retval = false;
const EVP_MD *hash = NULL;
Expand All @@ -2165,6 +2164,7 @@ static bool _cjose_jwe_calc_auth_tag(const char *enc, cjose_jwe_t *jwe, uint8_t
return false;
}

const char *digest_name = EVP_MD_get0_name(hash);
uint8_t *msg = NULL;

// calculate the Authentication Tag value over AAD + IV + ciphertext + AAD length
Expand Down Expand Up @@ -2215,7 +2215,8 @@ static bool _cjose_jwe_calc_auth_tag(const char *enc, cjose_jwe_t *jwe, uint8_t
memcpy(p, &al, sizeof(uint64_t));

// HMAC the input
if (!HMAC(hash, jwe->cek, jwe->cek_len / 2, msg, msg_len, md, md_len))
if (NULL
== EVP_Q_mac(NULL, "HMAC", NULL, digest_name, NULL, jwe->cek, jwe->cek_len / 2, msg, msg_len, md, EVP_MAX_MD_SIZE, md_len))
{
CJOSE_ERROR(err, CJOSE_ERR_CRYPTO);
goto _cjose_jwe_calc_auth_tag_end;
Expand Down Expand Up @@ -2310,9 +2311,9 @@ static bool _cjose_jwe_encrypt_dat_aes_cbc(cjose_jwe_t *jwe, const uint8_t *plai
jwe->enc_ct.raw_len += bytes_encrypted;

// calculate Authentication Tag
unsigned int tag_len = 0;
size_t tag_len = 0;
uint8_t tag[EVP_MAX_MD_SIZE];
if (_cjose_jwe_calc_auth_tag(enc, jwe, (unsigned char *)&tag, &tag_len, err) == false)
if (_cjose_jwe_calc_auth_tag(enc, jwe, tag, &tag_len, err) == false)
{
goto _cjose_jwe_encrypt_dat_aes_cbc_fail;
}
Expand Down Expand Up @@ -2463,9 +2464,9 @@ static bool _cjose_jwe_decrypt_dat_aes_cbc(cjose_jwe_t *jwe, cjose_err *err)
}

// calculate Authentication Tag
unsigned int tag_len = 0;
size_t tag_len = 0;
uint8_t tag[EVP_MAX_MD_SIZE];
if (_cjose_jwe_calc_auth_tag(enc, jwe, (unsigned char *)&tag, &tag_len, err) == false)
if (_cjose_jwe_calc_auth_tag(enc, jwe, tag, &tag_len, err) == false)
{
return false;
}
Expand Down
16 changes: 11 additions & 5 deletions src/jwk.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,6 @@
#include <openssl/rand.h>
#include <openssl/rsa.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/param_build.h>

// internal data structures
Expand Down Expand Up @@ -2623,7 +2622,7 @@ bool cjose_jwk_hkdf(const EVP_MD *md,
const uint8_t *ikm,
size_t ikm_len,
uint8_t *okm,
unsigned int okm_len,
size_t okm_len,
cjose_err *err)
{
// current impl. is very limited: SHA256, 256 bit output, and no info
Expand All @@ -2633,18 +2632,25 @@ bool cjose_jwk_hkdf(const EVP_MD *md,
return false;
}

const char *digest_name = EVP_MD_get0_name(md);

// HKDF-Extract, HMAC-SHA256(salt, IKM) -> PRK
unsigned int prk_len;
size_t prk_len = 0;
unsigned char prk[EVP_MAX_MD_SIZE];
if (NULL == HMAC(md, salt, salt_len, ikm, ikm_len, prk, &prk_len))

if (NULL == EVP_Q_mac(NULL, "HMAC", NULL, digest_name, NULL, salt, salt_len, ikm, ikm_len, prk, sizeof(prk), &prk_len)
|| prk_len != EVP_MD_get_size(md))
{
CJOSE_ERROR(err, CJOSE_ERR_CRYPTO);
_cjose_cleanse(prk, sizeof(prk));
return false;
}

// HKDF-Expand, HMAC-SHA256(PRK,0x01) -> OKM
const unsigned char t[] = { 0x01 };
if (NULL == HMAC(md, prk, prk_len, t, sizeof(t), okm, NULL))
size_t output_len = 0;
if (NULL == EVP_Q_mac(NULL, "HMAC", NULL, digest_name, NULL, prk, prk_len, t, sizeof(t), okm, okm_len, &output_len)
|| output_len != okm_len)
{
CJOSE_ERROR(err, CJOSE_ERR_CRYPTO);
_cjose_cleanse(prk, sizeof(prk));
Expand Down
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