Fix the PKCS#7 stuff: signature verify could fail if attributes reordered, the

detached data encoding was wrong and free up public keys.

CHANGES

@@ -5,6 +5,12 @@
 
  Changes between 0.9.1c and 0.9.2
 
+  *) Add a bunch of fixes to the PKCS#7 stuff. It used to sometimes reorder
+     signed attributes when verifying signatures (this would break them), 
+     the detached data encoding was wrong and public keys obtained using
+     X509_get_pubkey() weren't freed.
+     [Steve Henson]
+
   *) Add text documentation for the BUFFER functions. Also added a work around
      to a Win95 console bug. This was triggered by the password read stuff: the
      last character typed gets carried over to the next fread(). If you were 

crypto/pkcs7/example.c

@@ -135,7 +135,7 @@ char **str2;
 			OBJ_create("1.9.9999","OID_example","Our example OID");
 	/* To retrieve */
 	so=PKCS7_get_signed_attribute(si,signed_seq2string_nid);
-	if (so->type == V_ASN1_SEQUENCE)
+	if (so && (so->type == V_ASN1_SEQUENCE))
 		{
 		ASN1_CTX c;
 		ASN1_STRING *s;

crypto/pkcs7/pk7_doit.c

@@ -185,6 +185,7 @@ BIO *bio;
 				}
 			pkey=X509_get_pubkey(ri->cert);
 			jj=EVP_PKEY_size(pkey);
+			EVP_PKEY_free(pkey);
 			if (max < jj) max=jj;
 			}
 		if ((tmp=(unsigned char *)Malloc(max)) == NULL)
@@ -197,6 +198,7 @@ BIO *bio;
 			ri=(PKCS7_RECIP_INFO *)sk_value(rsk,i);
 			pkey=X509_get_pubkey(ri->cert);
 			jj=EVP_PKEY_encrypt(tmp,key,keylen,pkey);
+			EVP_PKEY_free(pkey);
 			if (jj <= 0)
 				{
 				PKCS7err(PKCS7_F_PKCS7_DATAINIT,ERR_R_EVP_LIB);
@@ -503,6 +505,11 @@ BIO *bio;
 	case NID_pkcs7_signed:
 		si_sk=p7->d.sign->signer_info;
 		os=p7->d.sign->contents->d.data;
+		/* If detached data then the content is excluded */
+		if(p7->detached) {
+			ASN1_OCTET_STRING_free(os);
+			p7->d.sign->contents->d.data = NULL;
+		}
 		break;
 		}
 
@@ -608,9 +615,7 @@ BIO *bio;
 			}
 		}
 
-	if (p7->detached)
-		ASN1_OCTET_STRING_set(os,(unsigned char *)"",0);
-	else
+	if (!p7->detached)
 		{
 		btmp=BIO_find_type(bio,BIO_TYPE_MEM);
 		if (btmp == NULL)
@@ -648,6 +653,7 @@ PKCS7_SIGNER_INFO *si;
 	STACK *sk,*cert;
 	BIO *btmp;
 	X509 *x509;
+	EVP_PKEY *pkey;
 
 	if (PKCS7_type_is_signed(p7))
 		{
@@ -742,22 +748,27 @@ for (ii=0; ii<md_len; ii++) printf("%02X",md_dat[ii]); printf(" calc\n");
 			}
 
 		EVP_VerifyInit(&mdc_tmp,EVP_get_digestbynid(md_type));
+		/* Note: when forming the encoding of the attributes we
+		 * shouldn't reorder them or this will break the signature.
+		 * This is done by using the IS_SEQUENCE flag.
+		 */
 		i=i2d_ASN1_SET(sk,NULL,i2d_X509_ATTRIBUTE,
-			V_ASN1_SET,V_ASN1_UNIVERSAL, IS_SET);
+			V_ASN1_SET,V_ASN1_UNIVERSAL, IS_SEQUENCE);
 		pp=(unsigned char *)Malloc(i);
 		p=pp;
 		i2d_ASN1_SET(sk,&p,i2d_X509_ATTRIBUTE,
-			V_ASN1_SET,V_ASN1_UNIVERSAL, IS_SET);
+			V_ASN1_SET,V_ASN1_UNIVERSAL, IS_SEQUENCE);
 		EVP_VerifyUpdate(&mdc_tmp,pp,i);
+
 		Free(pp);
 		}
 
 	os=si->enc_digest;
-	if (X509_get_pubkey(x509)->type == EVP_PKEY_DSA)
-		mdc_tmp.digest=EVP_dss1();
+	pkey = X509_get_pubkey(x509);
+	if(pkey->type == EVP_PKEY_DSA) mdc_tmp.digest=EVP_dss1();
 
-	i=EVP_VerifyFinal(&mdc_tmp,os->data,os->length,
-		X509_get_pubkey(x509));
+	i=EVP_VerifyFinal(&mdc_tmp,os->data,os->length, pkey);
+	EVP_PKEY_free(pkey);
 	if (i <= 0)
 		{
 		PKCS7err(PKCS7_F_PKCS7_DATAVERIFY,PKCS7_R_SIGNATURE_FAILURE);

crypto/pkcs7/verify.c

@@ -190,7 +190,7 @@ again:
 			BIO_printf(bio_out,"String 1 is %s\n",str1);
 			BIO_printf(bio_out,"String 2 is %s\n",str2);
 			}
-			
+
 		}
 
 	X509_STORE_free(cert_store);