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Merge pull request #693 from pabuhler/not-in-place-api
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Support a not in-place api's for protect/unprtect
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@pabuhler
pabuhler authored Jun 12, 2024
2 parents ca271bc + 703f2e9 commit 24eec55
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Showing 21 changed files with 1,632 additions and 717 deletions.
1 change: 1 addition & 0 deletions CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -458,6 +458,7 @@ if(LIBSRTP_TEST_APPS)
${ENABLE_WARNINGS_AS_ERRORS})
target_link_libraries(srtp_driver srtp2)
add_test(srtp_driver srtp_driver -v)
add_test(srtp_driver_not_in_place_io srtp_driver -v -n)

if(NOT (BUILD_SHARED_LIBS AND WIN32))
add_executable(test_srtp test/test_srtp.c)
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10 changes: 6 additions & 4 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -234,7 +234,7 @@ described in [RFC 7714](https://tools.ietf.org/html/rfc7714)
supports AES-128 & AES-256, so to use AES-192 or the AES-GCM group of ciphers a
3rd party crypto backend must be configured. For this and performance reasons it
is highly recommended to use a 3rd party crypto backend.

* The `srtp_protect()` function assumes that the buffer holding the
rtp packet has enough storage allocated that the authentication
tag can be written to the end of that packet. If this assumption
Expand Down Expand Up @@ -503,11 +503,13 @@ srtp_create(&session, &policy);
// main loop: get rtp packets, send srtp packets
while (1) {
char rtp_buffer[2048];
size_t len;
size_t rtp_len;
char srtp_buffer[2048];
size_t srtp_len = sizeof(srtp_buffer);

len = get_rtp_packet(rtp_buffer);
srtp_protect(session, rtp_buffer, &len);
send_srtp_packet(rtp_buffer, len);
srtp_protect(session, rtp_buffer, rtp_len, srtp_buffer, &srtp_len);
send_srtp_packet(srtp_buffer, srtp_len);
}
~~~

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32 changes: 23 additions & 9 deletions crypto/cipher/aes_gcm_mbedtls.c
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Original file line number Diff line number Diff line change
Expand Up @@ -281,8 +281,10 @@ static srtp_err_status_t srtp_aes_gcm_mbedtls_set_aad(void *cv,
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_mbedtls_encrypt(void *cv,
uint8_t *buf,
size_t *enc_len)
const uint8_t *src,
size_t src_len,
uint8_t *dst,
size_t *dst_len)
{
FUNC_ENTRY();
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
Expand All @@ -292,16 +294,22 @@ static srtp_err_status_t srtp_aes_gcm_mbedtls_encrypt(void *cv,
return (srtp_err_status_bad_param);
}

errCode = mbedtls_gcm_crypt_and_tag(c->ctx, MBEDTLS_GCM_ENCRYPT, *enc_len,
if (*dst_len < src_len) {
return srtp_err_status_buffer_small;
}

errCode = mbedtls_gcm_crypt_and_tag(c->ctx, MBEDTLS_GCM_ENCRYPT, src_len,
c->iv, c->iv_len, c->aad, c->aad_size,
buf, buf, c->tag_len, c->tag);
src, dst, c->tag_len, c->tag);

c->aad_size = 0;
if (errCode != 0) {
debug_print(srtp_mod_aes_gcm, "mbedtls error code: %d", errCode);
return srtp_err_status_bad_param;
}

*dst_len = src_len;

return (srtp_err_status_ok);
}

Expand Down Expand Up @@ -337,8 +345,10 @@ static srtp_err_status_t srtp_aes_gcm_mbedtls_get_tag(void *cv,
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_mbedtls_decrypt(void *cv,
uint8_t *buf,
size_t *enc_len)
const uint8_t *src,
size_t src_len,
uint8_t *dst,
size_t *dst_len)
{
FUNC_ENTRY();
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
Expand All @@ -348,12 +358,16 @@ static srtp_err_status_t srtp_aes_gcm_mbedtls_decrypt(void *cv,
return (srtp_err_status_bad_param);
}

if (*dst_len < (src_len - c->tag_len)) {
return srtp_err_status_buffer_small;
}

debug_print(srtp_mod_aes_gcm, "AAD: %s",
srtp_octet_string_hex_string(c->aad, c->aad_size));

errCode = mbedtls_gcm_auth_decrypt(
c->ctx, (*enc_len - c->tag_len), c->iv, c->iv_len, c->aad, c->aad_size,
buf + (*enc_len - c->tag_len), c->tag_len, buf, buf);
c->ctx, (src_len - c->tag_len), c->iv, c->iv_len, c->aad, c->aad_size,
src + (src_len - c->tag_len), c->tag_len, src, dst);
c->aad_size = 0;
if (errCode != 0) {
return (srtp_err_status_auth_fail);
Expand All @@ -363,7 +377,7 @@ static srtp_err_status_t srtp_aes_gcm_mbedtls_decrypt(void *cv,
* Reduce the buffer size by the tag length since the tag
* is not part of the original payload
*/
*enc_len -= c->tag_len;
*dst_len = (src_len - c->tag_len);

return (srtp_err_status_ok);
}
Expand Down
64 changes: 43 additions & 21 deletions crypto/cipher/aes_gcm_nss.c
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Original file line number Diff line number Diff line change
Expand Up @@ -281,8 +281,10 @@ static srtp_err_status_t srtp_aes_gcm_nss_set_aad(void *cv,

static srtp_err_status_t srtp_aes_gcm_nss_do_crypto(void *cv,
bool encrypt,
uint8_t *buf,
size_t *enc_len)
const uint8_t *src,
size_t src_len,
uint8_t *dst,
size_t *dst_len)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;

Expand All @@ -299,13 +301,13 @@ static srtp_err_status_t srtp_aes_gcm_nss_do_crypto(void *cv,
SECItem param = { siBuffer, (unsigned char *)&c->params,
sizeof(CK_GCM_PARAMS) };
if (encrypt) {
rv = PK11_Encrypt(c->key, CKM_AES_GCM, &param, buf, &out_len,
*enc_len + 16, buf, *enc_len);
rv = PK11_Encrypt(c->key, CKM_AES_GCM, &param, dst, &out_len, *dst_len,
src, src_len);
} else {
rv = PK11_Decrypt(c->key, CKM_AES_GCM, &param, buf, &out_len, *enc_len,
buf, *enc_len);
rv = PK11_Decrypt(c->key, CKM_AES_GCM, &param, dst, &out_len, *dst_len,
src, src_len);
}
*enc_len = out_len;
*dst_len = out_len;
srtp_err_status_t status = (srtp_err_status_ok);
if (rv != SECSuccess) {
status = (srtp_err_status_cipher_fail);
Expand All @@ -328,32 +330,41 @@ static srtp_err_status_t srtp_aes_gcm_nss_do_crypto(void *cv,
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_nss_encrypt(void *cv,
uint8_t *buf,
size_t *enc_len)
const uint8_t *src,
size_t src_len,
uint8_t *dst,
size_t *dst_len)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;

// When we get a non-NULL buffer, we know that the caller is
// prepared to also take the tag. When we get a NULL buffer,
// When we get a non-NULL src buffer, we know that the caller is
// prepared to also take the tag. When we get a NULL src buffer,
// even though there's no data, we need to give NSS a buffer
// where it can write the tag. We can't just use c->tag because
// memcpy has undefined behavior on overlapping ranges.
uint8_t tagbuf[16];
uint8_t *non_null_buf = buf;
if (!non_null_buf && (*enc_len == 0)) {
const uint8_t *non_null_buf = src;
uint8_t *non_null_dst_buf = dst;
if (!non_null_buf && (src_len == 0)) {
non_null_buf = tagbuf;
non_null_dst_buf = tagbuf;
*dst_len = sizeof(tagbuf);
} else if (!non_null_buf) {
return srtp_err_status_bad_param;
}

srtp_err_status_t status =
srtp_aes_gcm_nss_do_crypto(cv, true, non_null_buf, enc_len);
srtp_err_status_t status = srtp_aes_gcm_nss_do_crypto(
cv, true, non_null_buf, src_len, non_null_dst_buf, dst_len);
if (status != srtp_err_status_ok) {
return status;
}

memcpy(c->tag, non_null_buf + (*enc_len - c->tag_size), c->tag_size);
*enc_len -= c->tag_size;
if (*dst_len < c->tag_size) {
return srtp_err_status_bad_param;
}

memcpy(c->tag, non_null_dst_buf + (*dst_len - c->tag_size), c->tag_size);
*dst_len -= c->tag_size;
return srtp_err_status_ok;
}

Expand Down Expand Up @@ -387,11 +398,22 @@ static srtp_err_status_t srtp_aes_gcm_nss_get_tag(void *cv,
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_nss_decrypt(void *cv,
uint8_t *buf,
size_t *enc_len)
const uint8_t *src,
size_t src_len,
uint8_t *dst,
size_t *dst_len)
{
srtp_err_status_t status =
srtp_aes_gcm_nss_do_crypto(cv, false, buf, enc_len);
uint8_t tagbuf[16];
uint8_t *non_null_dst_buf = dst;
if (!non_null_dst_buf && (*dst_len == 0)) {
non_null_dst_buf = tagbuf;
*dst_len = sizeof(tagbuf);
} else if (!non_null_dst_buf) {
return srtp_err_status_bad_param;
}

srtp_err_status_t status = srtp_aes_gcm_nss_do_crypto(
cv, false, src, src_len, non_null_dst_buf, dst_len);
if (status != srtp_err_status_ok) {
int err = PR_GetError();
if (err == SEC_ERROR_BAD_DATA) {
Expand Down
26 changes: 17 additions & 9 deletions crypto/cipher/aes_gcm_ossl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -293,8 +293,10 @@ static srtp_err_status_t srtp_aes_gcm_openssl_set_aad(void *cv,
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_openssl_encrypt(void *cv,
uint8_t *buf,
size_t *enc_len)
const uint8_t *src,
size_t src_len,
uint8_t *dst,
size_t *dst_len)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
if (c->dir != srtp_direction_encrypt && c->dir != srtp_direction_decrypt) {
Expand All @@ -304,7 +306,8 @@ static srtp_err_status_t srtp_aes_gcm_openssl_encrypt(void *cv,
/*
* Encrypt the data
*/
EVP_Cipher(c->ctx, buf, buf, *enc_len);
EVP_Cipher(c->ctx, dst, src, src_len);
*dst_len = src_len;

return (srtp_err_status_ok);
}
Expand Down Expand Up @@ -354,8 +357,10 @@ static srtp_err_status_t srtp_aes_gcm_openssl_get_tag(void *cv,
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_openssl_decrypt(void *cv,
uint8_t *buf,
size_t *enc_len)
const uint8_t *src,
size_t src_len,
uint8_t *dst,
size_t *dst_len)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
if (c->dir != srtp_direction_encrypt && c->dir != srtp_direction_decrypt) {
Expand All @@ -364,12 +369,15 @@ static srtp_err_status_t srtp_aes_gcm_openssl_decrypt(void *cv,

/*
* Set the tag before decrypting
*
* explicitly cast away const of src
*/
if (!EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_SET_TAG, c->tag_len,
buf + (*enc_len - c->tag_len))) {
if (!EVP_CIPHER_CTX_ctrl(
c->ctx, EVP_CTRL_GCM_SET_TAG, c->tag_len,
(void *)(uintptr_t)(src + (src_len - c->tag_len)))) {
return (srtp_err_status_auth_fail);
}
EVP_Cipher(c->ctx, buf, buf, *enc_len - c->tag_len);
EVP_Cipher(c->ctx, dst, src, src_len - c->tag_len);

/*
* Check the tag
Expand All @@ -382,7 +390,7 @@ static srtp_err_status_t srtp_aes_gcm_openssl_decrypt(void *cv,
* Reduce the buffer size by the tag length since the tag
* is not part of the original payload
*/
*enc_len -= c->tag_len;
*dst_len = src_len -= c->tag_len;

return (srtp_err_status_ok);
}
Expand Down
31 changes: 18 additions & 13 deletions crypto/cipher/aes_gcm_wssl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -321,8 +321,10 @@ static srtp_err_status_t srtp_aes_gcm_wolfssl_set_aad(void *cv,
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_wolfssl_encrypt(void *cv,
unsigned char *buf,
size_t *enc_len)
const uint8_t *src,
size_t src_len,
uint8_t *dst,
size_t *dst_len)
{
FUNC_ENTRY();
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
Expand All @@ -333,17 +335,18 @@ static srtp_err_status_t srtp_aes_gcm_wolfssl_encrypt(void *cv,
}

#ifndef WOLFSSL_AESGCM_STREAM
err = wc_AesGcmEncrypt(c->ctx, buf, buf, *enc_len, c->iv, c->iv_len, c->tag,
err = wc_AesGcmEncrypt(c->ctx, dst, src, src_len, c->iv, c->iv_len, c->tag,
c->tag_len, c->aad, c->aad_size);

c->aad_size = 0;
#else
err = wc_AesGcmEncryptUpdate(c->ctx, buf, buf, *enc_len, NULL, 0);
err = wc_AesGcmEncryptUpdate(c->ctx, dst, src, src_len, NULL, 0);
#endif
if (err < 0) {
debug_print(srtp_mod_aes_gcm, "wolfSSL error code: %d", err);
return srtp_err_status_bad_param;
}
*dst_len = src_len;

return (srtp_err_status_ok);
}
Expand Down Expand Up @@ -392,8 +395,10 @@ static srtp_err_status_t srtp_aes_gcm_wolfssl_get_tag(void *cv,
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_wolfssl_decrypt(void *cv,
unsigned char *buf,
size_t *enc_len)
const uint8_t *src,
size_t src_len,
uint8_t *dst,
size_t *dst_len)
{
FUNC_ENTRY();
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
Expand All @@ -407,19 +412,19 @@ static srtp_err_status_t srtp_aes_gcm_wolfssl_decrypt(void *cv,
debug_print(srtp_mod_aes_gcm, "AAD: %s",
srtp_octet_string_hex_string(c->aad, c->aad_size));

err = wc_AesGcmDecrypt(c->ctx, buf, buf, (*enc_len - c->tag_len), c->iv,
c->iv_len, buf + (*enc_len - c->tag_len), c->tag_len,
err = wc_AesGcmDecrypt(c->ctx, dst, src, (src_len - c->tag_len), c->iv,
c->iv_len, src + (src_len - c->tag_len), c->tag_len,
c->aad, c->aad_size);
c->aad_size = 0;
#else
err = wc_AesGcmDecryptUpdate(c->ctx, buf, buf, (*enc_len - c->tag_len),
NULL, 0);
err = wc_AesGcmDecryptUpdate(c->ctx, dst, src, (src_len - c->tag_len), NULL,
0);
if (err < 0) {
debug_print(srtp_mod_aes_gcm, "wolfSSL error code: %d", err);
return (srtp_err_status_algo_fail);
}
err = wc_AesGcmDecryptFinal(c->ctx, buf + (*enc_len - c->tag_len),
c->tag_len);
err =
wc_AesGcmDecryptFinal(c->ctx, src + (src_len - c->tag_len), c->tag_len);
#endif
if (err < 0) {
debug_print(srtp_mod_aes_gcm, "wolfSSL error code: %d", err);
Expand All @@ -430,7 +435,7 @@ static srtp_err_status_t srtp_aes_gcm_wolfssl_decrypt(void *cv,
* Reduce the buffer size by the tag length since the tag
* is not part of the original payload
*/
*enc_len -= c->tag_len;
*dst_len = src_len -= c->tag_len;

return (srtp_err_status_ok);
}
Expand Down
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