3 files changed, 27 insertions, 4 deletions

diff --git a/src/lib/libcrypto/cms/cms_env.c b/src/lib/libcrypto/cms/cms_env.c
index 8640f459fb..74d957eee0 100644
--- a/src/lib/libcrypto/cms/cms_env.c
+++ b/src/lib/libcrypto/cms/cms_env.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cms_env.c,v 1.22 2019/08/11 11:07:40 jsing Exp $ */
+/* $OpenBSD: cms_env.c,v 1.23 2019/10/04 18:03:56 tb Exp $ */
 /*
  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project.
@@ -426,6 +426,7 @@ cms_RecipientInfo_ktri_decrypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri)
         EVP_PKEY *pkey = ktri->pkey;
         unsigned char *ek = NULL;
         size_t eklen;
+        size_t fixlen = 0;
         int ret = 0;
         CMS_EncryptedContentInfo *ec;
 
@@ -436,6 +437,19 @@ cms_RecipientInfo_ktri_decrypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri)
                 return 0;
         }
 
+        if (cms->d.envelopedData->encryptedContentInfo->havenocert &&
+            !cms->d.envelopedData->encryptedContentInfo->debug) {
+                X509_ALGOR *calg = ec->contentEncryptionAlgorithm;
+                const EVP_CIPHER *ciph;
+
+                if ((ciph = EVP_get_cipherbyobj(calg->algorithm)) == NULL) {
+                        CMSerror(CMS_R_UNKNOWN_CIPHER);
+                        return 0;
+                }
+
+                fixlen = EVP_CIPHER_key_length(ciph);
+        }
+
         ktri->pctx = EVP_PKEY_CTX_new(pkey, NULL);
         if (ktri->pctx == NULL)
                 return 0;
@@ -453,8 +467,11 @@ cms_RecipientInfo_ktri_decrypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri)
         }
 
         if (EVP_PKEY_decrypt(ktri->pctx, NULL, &eklen, ktri->encryptedKey->data,
-            ktri->encryptedKey->length) <= 0)
+            ktri->encryptedKey->length) <= 0 || eklen == 0 ||
+            (fixlen != 0 && eklen != fixlen)) {
+                CMSerror(CMS_R_CMS_LIB);
                 goto err;
+        }
 
         ek = malloc(eklen);
 
diff --git a/src/lib/libcrypto/cms/cms_lcl.h b/src/lib/libcrypto/cms/cms_lcl.h
index a8ccaf4488..8083e5537d 100644
--- a/src/lib/libcrypto/cms/cms_lcl.h
+++ b/src/lib/libcrypto/cms/cms_lcl.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: cms_lcl.h,v 1.11 2019/08/11 10:26:04 jsing Exp $ */
+/* $OpenBSD: cms_lcl.h,v 1.12 2019/10/04 18:03:56 tb Exp $ */
 /*
  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project.
@@ -170,6 +170,8 @@ struct CMS_EncryptedContentInfo_st {
         size_t keylen;
         /* Set to 1 if we are debugging decrypt and don't fake keys for MMA */
         int debug;
+        /* Set to 1 if we have no cert and need exta safety measures for MMA */
+        int havenocert;
 };
 
 struct CMS_RecipientInfo_st {
diff --git a/src/lib/libcrypto/cms/cms_smime.c b/src/lib/libcrypto/cms/cms_smime.c
index d39ee19aa5..367810f40e 100644
--- a/src/lib/libcrypto/cms/cms_smime.c
+++ b/src/lib/libcrypto/cms/cms_smime.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cms_smime.c,v 1.23 2019/08/11 14:51:15 jsing Exp $ */
+/* $OpenBSD: cms_smime.c,v 1.24 2019/10/04 18:03:56 tb Exp $ */
 /*
  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project.
@@ -823,6 +823,10 @@ CMS_decrypt(CMS_ContentInfo *cms, EVP_PKEY *pk, X509 *cert, BIO *dcont,
                 cms->d.envelopedData->encryptedContentInfo->debug = 1;
         else
                 cms->d.envelopedData->encryptedContentInfo->debug = 0;
+        if (!cert)
+                cms->d.envelopedData->encryptedContentInfo->havenocert = 1;
+        else
+                cms->d.envelopedData->encryptedContentInfo->havenocert = 0;
         if (!pk && !cert && !dcont && !out)
                 return 1;
         if (pk && !CMS_decrypt_set1_pkey(cms, pk, cert))