add test for degenerate case and allow degenerate case by default

certs/include.am

@@ -37,6 +37,7 @@ EXTRA_DIST += \
 	     certs/server-revoked-cert.pem \
 	     certs/server-revoked-key.pem \
 	     certs/wolfssl-website-ca.pem \
+	     certs/test-degenerate.p7b \
 	     certs/test-servercert.p12 \
 	     certs/ecc-rsa-server.p12 \
 	     certs/dsaparams.pem \

certs/renewcerts.sh

@@ -30,6 +30,9 @@
 #                       crl/crl.revoked
 #                       crl/eccCliCRL.pem
 #                       crl/eccSrvCRL.pem
+#
+#                       pkcs7:
+#                       test-degenerate.p7b
 # if HAVE_NTRU
 #                       ntru-cert.pem
 #                       ntru-key.raw
@@ -570,6 +573,19 @@ run_renewcerts(){
     echo "ran ./gencrls.sh"
     echo ""
 
+    ############################################################
+    ########## generate PKCS7 bundles ##########################
+    ############################################################
+    echo "Changing directory to wolfssl certs..."
+    echo ""
+    cd ../ || exit 1
+    echo "Creating test-degenerate.p7b..."
+    echo ""
+    openssl crl2pkcs7 -nocrl -certfile ./client-cert.pem -out test-degenerate.p7b -outform DER
+    check_result $? ""
+    echo "End of section"
+    echo "---------------------------------------------------------------------"
+
     #cleanup the file system now that we're done
     echo "Performing final steps, cleaning up the file system..."
     echo ""

tests/api.c

@@ -15897,6 +15897,42 @@ static void test_wc_PKCS7_EncodeEncryptedData (void)
 #endif
 } /* END test_wc_PKCS7_EncodeEncryptedData() */
 
+/*
+ * Testing wc_PKCS7_Degenerate()
+ */
+static void test_wc_PKCS7_Degenerate(void)
+{
+#if defined(HAVE_PKCS7) && !defined(NO_FILESYSTEM)
+    PKCS7  pkcs7;
+    char   fName[] = "./certs/test-degenerate.p7b";
+    XFILE  f;
+    byte   der[4096];
+    word32 derSz;
+
+    printf(testingFmt, "wc_PKCS7_Degenerate()");
+
+    AssertNotNull(f = XFOPEN(fName, "rb"));
+    AssertIntGT((derSz = fread(der, 1, sizeof(der), f)), 0);
+    XFCLOSE(f);
+
+    /* test degenerate success */
+    AssertIntEQ(wc_PKCS7_Init(&pkcs7, HEAP_HINT, INVALID_DEVID), 0);
+    AssertIntEQ(wc_PKCS7_InitWithCert(&pkcs7, NULL, 0), 0);
+    AssertIntEQ(wc_PKCS7_VerifySignedData(&pkcs7, der, derSz), 0);
+    wc_PKCS7_Free(&pkcs7);
+
+    /* test with turning off degenerate cases */
+    AssertIntEQ(wc_PKCS7_Init(&pkcs7, HEAP_HINT, INVALID_DEVID), 0);
+    AssertIntEQ(wc_PKCS7_InitWithCert(&pkcs7, NULL, 0), 0);
+    wc_PKCS7_AllowDegenerate(&pkcs7, 0); /* override allowing degenerate case */
+    AssertIntEQ(wc_PKCS7_VerifySignedData(&pkcs7, der, derSz), PKCS7_NO_SIGNER_E);
+    wc_PKCS7_Free(&pkcs7);
+
+    printf(resultFmt, passed);
+#endif
+} /* END test_wc_PKCS7_Degenerate() */
+
+
 /* Testing wc_SignatureGetSize() for signature type ECC */
 static int test_wc_SignatureGetSize_ecc(void)
 {
@@ -22474,6 +22510,7 @@ void ApiTest(void)
     test_wc_PKCS7_VerifySignedData();
     test_wc_PKCS7_EncodeDecodeEnvelopedData();
     test_wc_PKCS7_EncodeEncryptedData();
+    test_wc_PKCS7_Degenerate();
 
     test_wolfSSL_CTX_LoadCRL();
 

wolfcrypt/src/pkcs7.c

@@ -1897,7 +1897,33 @@ static int wc_PKCS7_ParseAttribs(PKCS7* pkcs7, byte* in, int inSz)
     return found;
 }
 
-/* Finds the certificates in the message and saves it. */
+
+/* option to turn off support for degenerate cases
+ * flag 0 turns off support
+ * flag 1 turns on support
+ *
+ * by default support for SignedData degenerate cases is on
+ */
+void wc_PKCS7_AllowDegenerate(PKCS7* pkcs7, word16 flag)
+{
+    if (pkcs7) {
+        if (flag) { /* flag of 1 turns on support for degenerate */
+            pkcs7->noDegenerate = 0;
+        }
+        else { /* flag of 0 turns off support */
+            pkcs7->noDegenerate = 1;
+        }
+    }
+}
+
+/* Finds the certificates in the message and saves it. By default allows
+ * degenerate cases which can have no signer.
+ *
+ * By default expects type SIGNED_DATA (SignedData) which can have any number of
+ * elements in signerInfos collection, inluding zero. (RFC2315 section 9.1)
+ * When adding support for the case of SignedAndEnvelopedData content types a
+ * signer is required. In this case the PKCS7 flag noDegenerate could be set.
+ */
 static int PKCS7_VerifySignedData(PKCS7* pkcs7, const byte* hashBuf,
     word32 hashSz, byte* pkiMsg, word32 pkiMsgSz,
     byte* pkiMsg2, word32 pkiMsg2Sz)
@@ -1993,6 +2019,9 @@ static int PKCS7_VerifySignedData(PKCS7* pkcs7, const byte* hashBuf,
     /* Skip the set. */
     idx += length;
     degenerate = (length == 0)? 1 : 0;
+    if (pkcs7->noDegenerate == 1 && degenerate == 1) {
+        return PKCS7_NO_SIGNER_E;
+    }
 
     /* Get the inner ContentInfo sequence */
     if (GetSequence(pkiMsg, &idx, &length, totalSz) < 0)
@@ -2135,8 +2164,10 @@ static int PKCS7_VerifySignedData(PKCS7* pkcs7, const byte* hashBuf,
     /* update idx if successful */
     if (ret == 0)
         idx = localIdx;
-    else
+    else {
-         pkiMsg2 = pkiMsg;
+         pkiMsg2   = pkiMsg;
+         pkiMsg2Sz = pkiMsgSz;
+    }
 
     /* If getting the content info failed with non degenerate then return the
      * error case. Otherwise with a degenerate it is ok if the content
@@ -2223,88 +2254,96 @@ static int PKCS7_VerifySignedData(PKCS7* pkcs7, const byte* hashBuf,
     if (GetSet(pkiMsg2, &idx, &length, pkiMsg2Sz) < 0)
         return ASN_PARSE_E;
 
-    if (length == 0)
+    /* require a signer if degenerate case not allowed */
+    if (length == 0 && pkcs7->noDegenerate == 1)
         return PKCS7_NO_SIGNER_E;
 
-    /* Get the sequence of the first signerInfo */
+    if (degenerate == 0 && length == 0) {
-    if (GetSequence(pkiMsg2, &idx, &length, pkiMsg2Sz) < 0)
+        WOLFSSL_MSG("PKCS7 signers expected");
-        return ASN_PARSE_E;
+        return PKCS7_NO_SIGNER_E;
-
-    /* Get the version */
-    if (GetMyVersion(pkiMsg2, &idx, &version, pkiMsg2Sz) < 0)
-        return ASN_PARSE_E;
-
-    if (version != 1) {
-        WOLFSSL_MSG("PKCS#7 signerInfo needs to be of version 1");
-        return ASN_VERSION_E;
     }
 
-    /* Get the sequence of IssuerAndSerialNumber */
+    if (length > 0 && degenerate == 0) {
-    if (GetSequence(pkiMsg2, &idx, &length, pkiMsg2Sz) < 0)
+        /* Get the sequence of the first signerInfo */
-        return ASN_PARSE_E;
+        if (GetSequence(pkiMsg2, &idx, &length, pkiMsg2Sz) < 0)
-
-    /* Skip it */
-    idx += length;
-
-    /* Get the sequence of digestAlgorithm */
-    if (GetAlgoId(pkiMsg2, &idx, &hashOID, oidHashType, pkiMsg2Sz) < 0) {
-        return ASN_PARSE_E;
-    }
-    pkcs7->hashOID = (int)hashOID;
-
-    /* Get the IMPLICIT[0] SET OF signedAttributes */
-    if (pkiMsg2[idx] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0)) {
-        idx++;
-
-        if (GetLength(pkiMsg2, &idx, &length, pkiMsg2Sz) < 0)
             return ASN_PARSE_E;
 
-        /* save pointer and length */
+        /* Get the version */
-        signedAttrib = &pkiMsg2[idx];
+        if (GetMyVersion(pkiMsg2, &idx, &version, pkiMsg2Sz) < 0)
-        signedAttribSz = length;
+            return ASN_PARSE_E;
 
-        if (wc_PKCS7_ParseAttribs(pkcs7, signedAttrib, signedAttribSz) <0) {
+        if (version != 1) {
-            WOLFSSL_MSG("Error parsing signed attributes");
+            WOLFSSL_MSG("PKCS#7 signerInfo needs to be of version 1");
+            return ASN_VERSION_E;
+        }
+
+        /* Get the sequence of IssuerAndSerialNumber */
+        if (GetSequence(pkiMsg2, &idx, &length, pkiMsg2Sz) < 0)
+            return ASN_PARSE_E;
+
+        /* Skip it */
+        idx += length;
+
+        /* Get the sequence of digestAlgorithm */
+        if (GetAlgoId(pkiMsg2, &idx, &hashOID, oidHashType, pkiMsg2Sz) < 0) {
+            return ASN_PARSE_E;
+        }
+        pkcs7->hashOID = (int)hashOID;
+
+        /* Get the IMPLICIT[0] SET OF signedAttributes */
+        if (pkiMsg2[idx] == (ASN_CONSTRUCTED | ASN_CONTEXT_SPECIFIC | 0)) {
+            idx++;
+
+            if (GetLength(pkiMsg2, &idx, &length, pkiMsg2Sz) < 0)
+                return ASN_PARSE_E;
+
+            /* save pointer and length */
+            signedAttrib = &pkiMsg2[idx];
+            signedAttribSz = length;
+
+            if (wc_PKCS7_ParseAttribs(pkcs7, signedAttrib, signedAttribSz) <0) {
+                WOLFSSL_MSG("Error parsing signed attributes");
+                return ASN_PARSE_E;
+            }
+
+            idx += length;
+        }
+
+        /* Get digestEncryptionAlgorithm */
+        if (GetAlgoId(pkiMsg2, &idx, &sigOID, oidSigType, pkiMsg2Sz) < 0) {
             return ASN_PARSE_E;
         }
 
-        idx += length;
+        /* store public key type based on digestEncryptionAlgorithm */
-    }
+        ret = wc_PKCS7_SetPublicKeyOID(pkcs7, sigOID);
+        if (ret <= 0) {
+            WOLFSSL_MSG("Failed to set public key OID from signature");
+            return ret;
+        }
 
-    /* Get digestEncryptionAlgorithm */
+        /* Get the signature */
-    if (GetAlgoId(pkiMsg2, &idx, &sigOID, oidSigType, pkiMsg2Sz) < 0) {
+        if (pkiMsg2[idx] == ASN_OCTET_STRING) {
-        return ASN_PARSE_E;
+            idx++;
-    }
 
-    /* store public key type based on digestEncryptionAlgorithm */
+            if (GetLength(pkiMsg2, &idx, &length, pkiMsg2Sz) < 0)
-    ret = wc_PKCS7_SetPublicKeyOID(pkcs7, sigOID);
+                return ASN_PARSE_E;
-    if (ret <= 0) {
-        WOLFSSL_MSG("Failed to set public key OID from signature");
-        return ret;
-    }
 
-    /* Get the signature */
+            /* save pointer and length */
-    if (pkiMsg2[idx] == ASN_OCTET_STRING) {
+            sig = &pkiMsg2[idx];
-        idx++;
+            sigSz = length;
 
-        if (GetLength(pkiMsg2, &idx, &length, pkiMsg2Sz) < 0)
+            idx += length;
-            return ASN_PARSE_E;
+        }
 
-        /* save pointer and length */
+        pkcs7->content = content;
-        sig = &pkiMsg2[idx];
+        pkcs7->contentSz = contentSz;
-        sigSz = length;
 
-        idx += length;
+        ret = wc_PKCS7_SignedDataVerifySignature(pkcs7, sig, sigSz,
-    }
-
-    pkcs7->content = content;
-    pkcs7->contentSz = contentSz;
-
-    ret = wc_PKCS7_SignedDataVerifySignature(pkcs7, sig, sigSz,
                                              signedAttrib, signedAttribSz,
                                              hashBuf, hashSz);
-    if (ret < 0)
+        if (ret < 0)
-        return ret;
+            return ret;
+    }
 
     return 0;
 }

wolfssl/wolfcrypt/pkcs7.h

@@ -145,6 +145,7 @@ typedef struct PKCS7 {
     
      /* flags - up to 16-bits */
     word16 isDynamic:1;
+    word16 noDegenerate:1; /* allow degenerate case in verify function */
 
     /* !! NEW DATA MEMBERS MUST BE ADDED AT END !! */
 } PKCS7;
@@ -164,6 +165,7 @@ WOLFSSL_API int  wc_PKCS7_EncodeSignedData(PKCS7* pkcs7,
 WOLFSSL_API int  wc_PKCS7_EncodeSignedData_ex(PKCS7* pkcs7, const byte* hashBuf, 
     word32 hashSz, byte* outputHead, word32* outputHeadSz, byte* outputFoot, 
     word32* outputFootSz);
+WOLFSSL_API void wc_PKCS7_AllowDegenerate(PKCS7* pkcs7, word16 flag);
 WOLFSSL_API int  wc_PKCS7_VerifySignedData(PKCS7* pkcs7,
                                        byte* pkiMsg, word32 pkiMsgSz);
 WOLFSSL_API int  wc_PKCS7_VerifySignedData_ex(PKCS7* pkcs7, const byte* hashBuf,