Rewrite CMS_SignerInfo_{sign,verify}()

Convert to using one-shot signing and verification. This is simpler than
doing Init/Update/Final and necessary for Ed25519 support (RFC 8419). Use
a single exit idiom, don't reuse the same buffer for decoding and signing
and simplify a few other things.

ok jsing

1 files changed, 55 insertions, 61 deletions

diff --git a/src/lib/libcrypto/cms/cms_sd.c b/src/lib/libcrypto/cms/cms_sd.c
index 89ba5bf01f..73f67ce4c3 100644
--- a/src/lib/libcrypto/cms/cms_sd.c
+++ b/src/lib/libcrypto/cms/cms_sd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cms_sd.c,v 1.26 2023/07/08 08:26:26 beck Exp $ */
+/* $OpenBSD: cms_sd.c,v 1.27 2023/09/11 09:24:14 tb Exp $ */
 /*
  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project.
@@ -721,119 +721,113 @@ cms_SignedData_final(CMS_ContentInfo *cms, BIO *chain)
 int
 CMS_SignerInfo_sign(CMS_SignerInfo *si)
 {
-        EVP_MD_CTX *mctx = si->mctx;
-        EVP_PKEY_CTX *pctx = NULL;
-        unsigned char *abuf = NULL;
-        int alen;
-        size_t siglen;
-        const EVP_MD *md = NULL;
+        const EVP_MD *md;
+        unsigned char *buf = NULL, *sig = NULL;
+        int buf_len = 0;
+        size_t sig_len = 0;
+        int ret = 0;
 
-        md = EVP_get_digestbyobj(si->digestAlgorithm->algorithm);
-        if (md == NULL)
-                return 0;
+        if ((md = EVP_get_digestbyobj(si->digestAlgorithm->algorithm)) == NULL)
+                goto err;
 
         if (CMS_signed_get_attr_by_NID(si, NID_pkcs9_signingTime, -1) < 0) {
                 if (!cms_add1_signingTime(si, NULL))
                         goto err;
         }
 
-        if (si->pctx)
-                pctx = si->pctx;
-        else {
-                EVP_MD_CTX_reset(mctx);
-                if (EVP_DigestSignInit(mctx, &pctx, md, NULL, si->pkey) <= 0)
+        if (si->pctx == NULL) {
+                EVP_MD_CTX_reset(si->mctx);
+                if (!EVP_DigestSignInit(si->mctx, &si->pctx, md, NULL, si->pkey))
                         goto err;
-                si->pctx = pctx;
         }
 
-        if (EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_SIGN,
+        if (EVP_PKEY_CTX_ctrl(si->pctx, -1, EVP_PKEY_OP_SIGN,
             EVP_PKEY_CTRL_CMS_SIGN, 0, si) <= 0) {
                 CMSerror(CMS_R_CTRL_ERROR);
                 goto err;
         }
 
-        alen = ASN1_item_i2d((ASN1_VALUE *)si->signedAttrs, &abuf,
-            &CMS_Attributes_Sign_it);
-        if (!abuf)
-                goto err;
-        if (EVP_DigestSignUpdate(mctx, abuf, alen) <= 0)
+        if ((buf_len = ASN1_item_i2d((ASN1_VALUE *)si->signedAttrs, &buf,
+            &CMS_Attributes_Sign_it)) <= 0) {
+                buf_len = 0;
                 goto err;
-        if (EVP_DigestSignFinal(mctx, NULL, &siglen) <= 0)
+        }
+        if (!EVP_DigestSign(si->mctx, NULL, &sig_len, buf, buf_len))
                 goto err;
-        free(abuf);
-        abuf = malloc(siglen);
-        if (abuf == NULL)
+        if ((sig = calloc(1, sig_len)) == NULL)
                 goto err;
-        if (EVP_DigestSignFinal(mctx, abuf, &siglen) <= 0)
+        if (!EVP_DigestSign(si->mctx, sig, &sig_len, buf, buf_len))
                 goto err;
 
-        if (EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_SIGN,
+        if (EVP_PKEY_CTX_ctrl(si->pctx, -1, EVP_PKEY_OP_SIGN,
             EVP_PKEY_CTRL_CMS_SIGN, 1, si) <= 0) {
                 CMSerror(CMS_R_CTRL_ERROR);
                 goto err;
         }
 
-        EVP_MD_CTX_reset(mctx);
+        ASN1_STRING_set0(si->signature, sig, sig_len);
+        sig = NULL;
 
-        ASN1_STRING_set0(si->signature, abuf, siglen);
-
-        return 1;
+        ret = 1;
 
  err:
-        free(abuf);
-        EVP_MD_CTX_reset(mctx);
+        if (si->mctx != NULL)
+                EVP_MD_CTX_reset(si->mctx);
+        freezero(buf, buf_len);
+        freezero(sig, sig_len);
 
-        return 0;
+        return ret;
 }
 LCRYPTO_ALIAS(CMS_SignerInfo_sign);
 
 int
 CMS_SignerInfo_verify(CMS_SignerInfo *si)
 {
-        EVP_MD_CTX *mctx = NULL;
-        unsigned char *abuf = NULL;
-        int alen, r = -1;
-        const EVP_MD *md = NULL;
+        const EVP_MD *md;
+        unsigned char *buf = NULL;
+        int buf_len = 0;
+        int ret = -1;
 
-        if (!si->pkey) {
+        if ((md = EVP_get_digestbyobj(si->digestAlgorithm->algorithm)) == NULL)
+                goto err;
+
+        if (si->pkey == NULL) {
                 CMSerror(CMS_R_NO_PUBLIC_KEY);
-                return -1;
+                goto err;
         }
 
-        md = EVP_get_digestbyobj(si->digestAlgorithm->algorithm);
-        if (md == NULL)
-                return -1;
-        if (si->mctx == NULL && (si->mctx = EVP_MD_CTX_new()) == NULL) {
+        if (si->mctx == NULL)
+                si->mctx = EVP_MD_CTX_new();
+        if (si->mctx == NULL) {
                 CMSerror(ERR_R_MALLOC_FAILURE);
-                return -1;
+                goto err;
         }
-        mctx = si->mctx;
-        if (EVP_DigestVerifyInit(mctx, &si->pctx, md, NULL, si->pkey) <= 0)
+
+        if (EVP_DigestVerifyInit(si->mctx, &si->pctx, md, NULL, si->pkey) <= 0)
                 goto err;
 
         if (!cms_sd_asn1_ctrl(si, 1))
                 goto err;
 
-        alen = ASN1_item_i2d((ASN1_VALUE *)si->signedAttrs, &abuf,
-            &CMS_Attributes_Verify_it);
-        if (!abuf)
-                goto err;
-        r = EVP_DigestVerifyUpdate(mctx, abuf, alen);
-        free(abuf);
-        if (r <= 0) {
-                r = -1;
+        if ((buf_len = ASN1_item_i2d((ASN1_VALUE *)si->signedAttrs, &buf,
+            &CMS_Attributes_Verify_it)) <= 0) {
+                buf_len = 0;
                 goto err;
         }
 
-        r = EVP_DigestVerifyFinal(mctx, si->signature->data,
-            si->signature->length);
-        if (r <= 0)
+        ret = EVP_DigestVerify(si->mctx, si->signature->data, si->signature->length,
+            buf, buf_len);
+        if (ret <= 0) {
                 CMSerror(CMS_R_VERIFICATION_FAILURE);
+                goto err;
+        }
 
  err:
-        EVP_MD_CTX_reset(mctx);
+        if (si->mctx != NULL)
+                EVP_MD_CTX_reset(si->mctx);
+        freezero(buf, buf_len);
 
-        return r;
+        return ret;
 }
 LCRYPTO_ALIAS(CMS_SignerInfo_verify);