Merge pull request #1859 from SparkiDev/pkcs7-cons

Support constructed OCTET_STRING in PKCS#7 signed data

wolfcrypt/src/pkcs7.c

@@ -376,6 +376,8 @@ void wc_PKCS7_Free(PKCS7* pkcs7)
     if (pkcs7->der != NULL)
         XFREE(pkcs7->der, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
 #endif
+    if (pkcs7->contentDynamic != NULL)
+        XFREE(pkcs7->contentDynamic, pkcs7->heap, DYNAMIC_TYPE_PKCS7);
 
     if (pkcs7->isDynamic) {
         pkcs7->isDynamic = 0;
@@ -1903,15 +1905,18 @@ static int PKCS7_VerifySignedData(PKCS7* pkcs7, const byte* hashBuf,
     word32 idx, contentType, hashOID, sigOID, totalSz;
     int length, version, ret;
     byte* content = NULL;
+    byte* contentDynamic = NULL;
     byte* sig = NULL;
     byte* cert = NULL;
     byte* signedAttrib = NULL;
     int contentSz = 0, sigSz = 0, certSz = 0, signedAttribSz = 0;
-    word32 localIdx;
+    word32 localIdx, start;
     byte degenerate;
 #ifdef ASN_BER_TO_DER
     byte* der;
 #endif
+    int multiPart = 0, keepContent;
+    int contentLen;
 
     if (pkcs7 == NULL || pkiMsg == NULL || pkiMsgSz == 0)
         return BAD_FUNC_ARG;
@@ -2011,43 +2016,127 @@ static int PKCS7_VerifySignedData(PKCS7* pkcs7, const byte* hashBuf,
     if (ret == 0 && GetLength(pkiMsg, &localIdx, &length, totalSz) <= 0)
         ret = ASN_PARSE_E;
 
-    if (ret == 0 && pkiMsg[localIdx++] != ASN_OCTET_STRING)
+    if (ret == 0 && pkiMsg[localIdx] == (ASN_OCTET_STRING | ASN_CONSTRUCTED)) {
-        ret = ASN_PARSE_E;
+        multiPart = 1;
 
-    if (ret == 0 && GetLength(pkiMsg, &localIdx, &length, totalSz) < 0)
+        localIdx++;
-        ret = ASN_PARSE_E;
+        /* Get length of all OCTET_STRINGs. */
+        if (GetLength(pkiMsg, &localIdx, &contentLen, totalSz) < 0)
+            ret = ASN_PARSE_E;
 
-    /* Save the inner data as the content. */
+        /* Check whether there is one OCTET_STRING inside. */
-    if (ret == 0 && length > 0) {
+        start = localIdx;
-        contentSz = length;
+        if (ret == 0 && pkiMsg[localIdx++] != ASN_OCTET_STRING)
+            ret = ASN_PARSE_E;
 
-        /* support using header and footer without content */
+        if (ret == 0 && GetLength(pkiMsg, &localIdx, &length, totalSz) < 0)
-        if (pkiMsg2 && pkiMsg2Sz > 0 && hashBuf && hashSz > 0) {
+            ret = ASN_PARSE_E;
-            /* Content not provided, use provided pkiMsg2 footer */
+
-            content = NULL;
+        if (ret == 0) {
-            localIdx = 0;
+            /* Use single OCTET_STRING directly. */
-            if (contentSz != (int)pkcs7->contentSz) {
+            if (localIdx - start + length == (word32)contentLen)
-                WOLFSSL_MSG("Data signed does not match contentSz provided");
+                multiPart = 0;
-                return BUFFER_E;
+            localIdx = start;
+        }
+    }
+    if (ret == 0 && multiPart) {
+        int i = 0;
+        keepContent = !(pkiMsg2 && pkiMsg2Sz > 0 && hashBuf && hashSz > 0);
+
+        if (keepContent) {
+            /* Create a buffer to hold content of OCTET_STRINGs. */
+            pkcs7->contentDynamic = XMALLOC(contentLen, pkcs7->heap,
+                                                            DYNAMIC_TYPE_PKCS7);
+            if (pkcs7->contentDynamic == NULL)
+                ret = MEMORY_E;
+        }
+
+        start = localIdx;
+        /* Use the data from each OCTET_STRING. */
+        while (ret == 0 && localIdx < start + contentLen) {
+            if (pkiMsg[localIdx++] != ASN_OCTET_STRING)
+                ret = ASN_PARSE_E;
+
+            if (ret == 0 && GetLength(pkiMsg, &localIdx, &length, totalSz) < 0)
+                ret = ASN_PARSE_E;
+            if (ret == 0 && length + localIdx > start + contentLen)
+                ret = ASN_PARSE_E;
+
+            if (ret == 0) {
+                if (keepContent) {
+                    XMEMCPY(pkcs7->contentDynamic + i, pkiMsg + localIdx,
+                                                                        length);
+                }
+                i += length;
+                localIdx += length;
+            }
+        }
+
+        length = i;
+        if (ret == 0 && length > 0) {
+            contentSz = length;
+
+            /* support using header and footer without content */
+            if (pkiMsg2 && pkiMsg2Sz > 0 && hashBuf && hashSz > 0) {
+                /* Content not provided, use provided pkiMsg2 footer */
+                content = NULL;
+                localIdx = 0;
+                if (contentSz != (int)pkcs7->contentSz) {
+                    WOLFSSL_MSG("Data signed does not match contentSz provided");
+                    return BUFFER_E;
+                }
+            }
+            else {
+                /* Content pointer for calculating hashes later */
+                content   = pkcs7->contentDynamic;
+                pkiMsg2   = pkiMsg;
+                pkiMsg2Sz = pkiMsgSz;
             }
         }
         else {
-            /* Content pointer for calculating hashes later */
-            content   = &pkiMsg[localIdx];
-            localIdx += length;
-
             pkiMsg2 = pkiMsg;
-            pkiMsg2Sz = pkiMsgSz;
         }
     }
-    else {
+    if (ret == 0 && !multiPart) {
-        pkiMsg2 = pkiMsg;
+        if (pkiMsg[localIdx++] != ASN_OCTET_STRING)
+            ret = ASN_PARSE_E;
+
+        if (ret == 0 && GetLength(pkiMsg, &localIdx, &length, totalSz) < 0)
+            ret = ASN_PARSE_E;
+
+        /* Save the inner data as the content. */
+        if (ret == 0 && length > 0) {
+            contentSz = length;
+
+            /* support using header and footer without content */
+            if (pkiMsg2 && pkiMsg2Sz > 0 && hashBuf && hashSz > 0) {
+                /* Content not provided, use provided pkiMsg2 footer */
+                content = NULL;
+                localIdx = 0;
+                if (contentSz != (int)pkcs7->contentSz) {
+                    WOLFSSL_MSG("Data signed does not match contentSz provided");
+                    return BUFFER_E;
+                }
+            }
+            else {
+                /* Content pointer for calculating hashes later */
+                content   = &pkiMsg[localIdx];
+                localIdx += length;
+
+                pkiMsg2 = pkiMsg;
+                pkiMsg2Sz = pkiMsgSz;
+            }
+        }
+        else {
+            pkiMsg2 = pkiMsg;
+        }
     }
 
     /* update idx if successful */
-    if (ret == 0) {
+    if (ret == 0)
         idx = localIdx;
-    }
+    else
+         pkiMsg2 = pkiMsg;
 
     /* If getting the content info failed with non degenerate then return the
      * error case. Otherwise with a degenerate it is ok if the content
@@ -2082,8 +2171,10 @@ static int PKCS7_VerifySignedData(PKCS7* pkcs7, const byte* hashBuf,
 #ifdef ASN_BER_TO_DER
             der = pkcs7->der;
 #endif
+            contentDynamic = pkcs7->contentDynamic;
             /* This will reset PKCS7 structure and then set the certificate */
             wc_PKCS7_InitWithCert(pkcs7, cert, certSz);
+            pkcs7->contentDynamic = contentDynamic;
 #ifdef ASN_BER_TO_DER
             pkcs7->der = der;
 #endif

wolfssl/wolfcrypt/pkcs7.h

@@ -102,6 +102,7 @@ typedef struct PKCS7 {
     WC_RNG* rng;
     PKCS7Attrib* signedAttribs;
     byte*  content;               /* inner content, not owner             */
+    byte*  contentDynamic;        /* content if constructed OCTET_STRING  */
     byte*  singleCert;            /* recipient cert, DER, not owner       */
     const byte* issuer;           /* issuer name of singleCert            */
     byte*  privateKey;            /* private key, DER, not owner          */