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Don't use the low level AES key wrap APIs in CMS

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We should not be using the low level AES APIs in CMS. Instead we should
be using EVP. There was a small amount of use of the low level key
wrap APIs - so we convert that to EVP.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/10580)
This commit is contained in:
Matt Caswell 2019-12-05 18:01:44 +00:00
parent b1558c0bc8
commit 2852c672a8
1 changed files with 59 additions and 22 deletions
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81
crypto/cms/cms_env.c
View File

@ -13,7 +13,7 @@
#include <openssl/x509v3.h>
#include <openssl/err.h>
#include <openssl/cms.h>
#include <openssl/aes.h>
#include <openssl/evp.h>
#include "cms_local.h"
#include "crypto/asn1.h"
#include "crypto/evp.h"
@ -625,6 +625,23 @@ int CMS_RecipientInfo_set0_key(CMS_RecipientInfo *ri,
return 1;
}
static const EVP_CIPHER *cms_get_key_wrap_cipher(size_t keylen)
{
switch(keylen) {
case 16:
return EVP_aes_128_wrap();
case 24:
return EVP_aes_192_wrap();
case 32:
return EVP_aes_256_wrap();
}
return NULL;
}
/* Encrypt content key in KEK recipient info */
static int cms_RecipientInfo_kekri_encrypt(const CMS_ContentInfo *cms,
@ -632,36 +649,50 @@ static int cms_RecipientInfo_kekri_encrypt(const CMS_ContentInfo *cms,
{
CMS_EncryptedContentInfo *ec;
CMS_KEKRecipientInfo *kekri;
AES_KEY actx;
unsigned char *wkey = NULL;
int wkeylen;
int r = 0;
const EVP_CIPHER *cipher = NULL;
int outlen = 0;
EVP_CIPHER_CTX *ctx = NULL;
ec = cms->d.envelopedData->encryptedContentInfo;
kekri = ri->d.kekri;
if (!kekri->key) {
if (kekri->key == NULL) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_ENCRYPT, CMS_R_NO_KEY);
return 0;
}
if (AES_set_encrypt_key(kekri->key, kekri->keylen << 3, &actx)) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_ENCRYPT,
CMS_R_ERROR_SETTING_KEY);
cipher = cms_get_key_wrap_cipher(kekri->keylen);
if (cipher == NULL) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_ENCRYPT, CMS_R_INVALID_KEY_LENGTH);
goto err;
}
/* 8 byte prefix for AES wrap ciphers */
wkey = OPENSSL_malloc(ec->keylen + 8);
if (wkey == NULL) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_ENCRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
wkeylen = AES_wrap_key(&actx, NULL, wkey, ec->key, ec->keylen);
ctx = EVP_CIPHER_CTX_new();
if (ctx == NULL) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_ENCRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
if (wkeylen <= 0) {
EVP_CIPHER_CTX_set_flags(ctx, EVP_CIPHER_CTX_FLAG_WRAP_ALLOW);
if (!EVP_EncryptInit_ex(ctx, cipher, NULL, kekri->key, NULL)
|| !EVP_EncryptUpdate(ctx, wkey, &wkeylen, ec->key, ec->keylen)
|| !EVP_EncryptFinal_ex(ctx, wkey + wkeylen, &outlen)) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_ENCRYPT, CMS_R_WRAP_ERROR);
goto err;
}
wkeylen += outlen;
if (!ossl_assert((size_t)wkeylen == ec->keylen + 8)) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_ENCRYPT, CMS_R_WRAP_ERROR);
goto err;
}
@ -671,10 +702,9 @@ static int cms_RecipientInfo_kekri_encrypt(const CMS_ContentInfo *cms,
r = 1;
err:
if (!r)
OPENSSL_free(wkey);
OPENSSL_cleanse(&actx, sizeof(actx));
EVP_CIPHER_CTX_free(ctx);
return r;
@ -687,10 +717,12 @@ static int cms_RecipientInfo_kekri_decrypt(CMS_ContentInfo *cms,
{
CMS_EncryptedContentInfo *ec;
CMS_KEKRecipientInfo *kekri;
AES_KEY actx;
unsigned char *ukey = NULL;
int ukeylen;
int r = 0, wrap_nid;
const EVP_CIPHER *cipher = NULL;
int outlen = 0;
EVP_CIPHER_CTX *ctx = NULL;
ec = cms->d.envelopedData->encryptedContentInfo;
@ -716,27 +748,33 @@ static int cms_RecipientInfo_kekri_decrypt(CMS_ContentInfo *cms,
goto err;
}
if (AES_set_decrypt_key(kekri->key, kekri->keylen << 3, &actx)) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_DECRYPT,
CMS_R_ERROR_SETTING_KEY);
cipher = cms_get_key_wrap_cipher(kekri->keylen);
if (cipher == NULL) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_DECRYPT, CMS_R_INVALID_KEY_LENGTH);
goto err;
}
ukey = OPENSSL_malloc(kekri->encryptedKey->length - 8);
if (ukey == NULL) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_DECRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
ukeylen = AES_unwrap_key(&actx, NULL, ukey,
kekri->encryptedKey->data,
kekri->encryptedKey->length);
ctx = EVP_CIPHER_CTX_new();
if (ctx == NULL) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_DECRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
if (ukeylen <= 0) {
if (!EVP_DecryptInit_ex(ctx, cipher, NULL, kekri->key, NULL)
|| !EVP_DecryptUpdate(ctx, ukey, &ukeylen,
kekri->encryptedKey->data,
kekri->encryptedKey->length)
|| !EVP_DecryptFinal_ex(ctx, ukey + ukeylen, &outlen)) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KEKRI_DECRYPT, CMS_R_UNWRAP_ERROR);
goto err;
}
ukeylen += outlen;
ec->key = ukey;
ec->keylen = ukeylen;
@ -744,10 +782,9 @@ static int cms_RecipientInfo_kekri_decrypt(CMS_ContentInfo *cms,
r = 1;
err:
if (!r)
OPENSSL_free(ukey);
OPENSSL_cleanse(&actx, sizeof(actx));
EVP_CIPHER_CTX_free(ctx);
return r;