X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/3af849e2045f7c580d4c533d829dc9d567162d36..3857519629ca8fbcf3466c3fc761a5bb6ed32d53:/src/src/pdkim/pdkim.c

diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c
index 138861815..30cb0437c 100644
--- a/src/src/pdkim/pdkim.c
+++ b/src/src/pdkim/pdkim.c
@@ -1,8 +1,10 @@
 /*
  *  PDKIM - a RFC4871 (DKIM) implementation
  *
+ *  Copyright (c) The Exim Maintainers 2021 - 2022
  *  Copyright (C) 2009 - 2016  Tom Kistner <tom@duncanthrax.net>
- *  Copyright (C) 2016 - 2017  Jeremy Harris <jgh@exim.org>
+ *  Copyright (C) 2016 - 2020  Jeremy Harris <jgh@exim.org>
+ *  SPDX-License-Identifier: GPL-2.0-or-later
  *
  *  http://duncanthrax.net/pdkim/
  *
@@ -26,8 +28,8 @@
 
 #ifndef DISABLE_DKIM	/* entire file */
 
-#ifndef SUPPORT_TLS
-# error Need SUPPORT_TLS for DKIM
+#ifdef DISABLE_TLS
+# error Must not DISABLE_TLS, for DKIM
 #endif
 
 #include "crypt_ver.h"
@@ -71,24 +73,29 @@ const uschar * pdkim_canons[] = {
   NULL
 };
 
-typedef struct {
-  const uschar * dkim_hashname;
-  hashmethod	 exim_hashmethod;
-} pdkim_hashtype;
-static const pdkim_hashtype pdkim_hashes[] = {
+const pdkim_hashtype pdkim_hashes[] = {
   { US"sha1",   HASH_SHA1 },
   { US"sha256", HASH_SHA2_256 },
   { US"sha512", HASH_SHA2_512 }
 };
 
 const uschar * pdkim_keytypes[] = {
-  US"rsa"
+  [KEYTYPE_RSA] =	US"rsa",
+#ifdef SIGN_HAVE_ED25519
+  [KEYTYPE_ED25519] =	US"ed25519",		/* Works for 3.6.0 GnuTLS, OpenSSL 1.1.1 */
+#endif
+
+#ifdef notyet_EC_dkim_extensions	/* https://tools.ietf.org/html/draft-srose-dkim-ecc-00 */
+  US"eccp256",
+  US"eccp348",
+  US"ed448",
+#endif
 };
 
 typedef struct pdkim_combined_canon_entry {
-  const uschar * str;
-  int canon_headers;
-  int canon_body;
+  const uschar *	str;
+  int			canon_headers;
+  int			canon_body;
 } pdkim_combined_canon_entry;
 
 pdkim_combined_canon_entry pdkim_combined_canons[] = {
@@ -102,7 +109,7 @@ pdkim_combined_canon_entry pdkim_combined_canons[] = {
 };
 
 
-static blob lineending = {.data = US"\r\n", .len = 2};
+static const blob lineending = {.data = US"\r\n", .len = 2};
 
 /* -------------------------------------------------------------------------- */
 uschar *
@@ -116,6 +123,40 @@ return string_sprintf("%s-%s",
 }
 
 
+static int
+pdkim_keyname_to_keytype(const uschar * s)
+{
+for (int i = 0; i < nelem(pdkim_keytypes); i++)
+  if (Ustrcmp(s, pdkim_keytypes[i]) == 0) return i;
+return -1;
+}
+
+int
+pdkim_hashname_to_hashtype(const uschar * s, unsigned len)
+{
+if (!len) len = Ustrlen(s);
+for (int i = 0; i < nelem(pdkim_hashes); i++)
+  if (Ustrncmp(s, pdkim_hashes[i].dkim_hashname, len) == 0)
+    return i;
+return -1;
+}
+
+void
+pdkim_cstring_to_canons(const uschar * s, unsigned len,
+  int * canon_head, int * canon_body)
+{
+if (!len) len = Ustrlen(s);
+for (int i = 0; pdkim_combined_canons[i].str; i++)
+  if (  Ustrncmp(s, pdkim_combined_canons[i].str, len) == 0
+     && len == Ustrlen(pdkim_combined_canons[i].str))
+    {
+    *canon_head = pdkim_combined_canons[i].canon_headers;
+    *canon_body = pdkim_combined_canons[i].canon_body;
+    break;
+    }
+}
+
+
 
 const char *
 pdkim_verify_status_str(int status)
@@ -142,6 +183,7 @@ switch(ext_status)
   case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE";
   case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: return "PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD";
   case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return "PDKIM_VERIFY_INVALID_PUBKEY_IMPORT";
+  case PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE: return "PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE";
   case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: return "PDKIM_VERIFY_INVALID_SIGNATURE_ERROR";
   case PDKIM_VERIFY_INVALID_DKIM_VERSION: return "PDKIM_VERIFY_INVALID_DKIM_VERSION";
   default: return "PDKIM_VERIFY_UNKNOWN";
@@ -155,10 +197,11 @@ switch(status)
   {
   case PDKIM_OK:		return US"OK";
   case PDKIM_FAIL:		return US"FAIL";
-  case PDKIM_ERR_RSA_PRIVKEY:	return US"RSA_PRIVKEY";
-  case PDKIM_ERR_RSA_SIGNING:	return US"RSA SIGNING";
-  case PDKIM_ERR_LONG_LINE:	return US"RSA_LONG_LINE";
+  case PDKIM_ERR_RSA_PRIVKEY:	return US"PRIVKEY";
+  case PDKIM_ERR_RSA_SIGNING:	return US"SIGNING";
+  case PDKIM_ERR_LONG_LINE:	return US"LONG_LINE";
   case PDKIM_ERR_BUFFER_TOO_SMALL:	return US"BUFFER_TOO_SMALL";
+  case PDKIM_ERR_EXCESS_SIGS:	return US"EXCESS_SIGS";
   case PDKIM_SIGN_PRIVKEY_WRAP:	return US"PRIVKEY_WRAP";
   case PDKIM_SIGN_PRIVKEY_B64D:	return US"PRIVKEY_B64D";
   default: return US"(unknown)";
@@ -168,11 +211,10 @@ switch(status)
 
 /* -------------------------------------------------------------------------- */
 /* Print debugging functions */
-static void
+void
 pdkim_quoteprint(const uschar *data, int len)
 {
-int i;
-for (i = 0; i < len; i++)
+for (int i = 0; i < len; i++)
   {
   const int c = data[i];
   switch (c)
@@ -194,11 +236,10 @@ for (i = 0; i < len; i++)
 debug_printf("\n");
 }
 
-static void
+void
 pdkim_hexprint(const uschar *data, int len)
 {
-int i;
-if (data) for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]);
+if (data) for (int i = 0 ; i < len; i++) debug_printf("%02x", data[i]);
 else debug_printf("<NULL>");
 debug_printf("\n");
 }
@@ -208,7 +249,7 @@ debug_printf("\n");
 static pdkim_stringlist *
 pdkim_prepend_stringlist(pdkim_stringlist * base, const uschar * str)
 {
-pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist));
+pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist), GET_UNTAINTED);
 
 memset(new_entry, 0, sizeof(pdkim_stringlist));
 new_entry->value = string_copy(str);
@@ -224,13 +265,13 @@ static void
 pdkim_strtrim(gstring * str)
 {
 uschar * p = str->s;
-uschar * q = p + str->ptr;
+uschar * q;
 
 while (*p == '\t' || *p == ' ')		/* dump the leading whitespace */
   { str->size--; str->ptr--; str->s++; }
 
 while (  str->ptr > 0
-      && (q = str->s + str->ptr - 1),  *q == '\t' || *q == ' '
+      && ((q = str->s + str->ptr - 1),  (*q == '\t' || *q == ' '))
       )
   str->ptr--;				/* dump trailing whitespace */
 
@@ -293,16 +334,15 @@ return PDKIM_FAIL;
 /* -------------------------------------------------------------------------- */
 /* Performs "relaxed" canonicalization of a header. */
 
-static uschar *
-pdkim_relax_header(const uschar * header, BOOL append_crlf)
+uschar *
+pdkim_relax_header_n(const uschar * header, int len, BOOL append_crlf)
 {
 BOOL past_field_name = FALSE;
 BOOL seen_wsp = FALSE;
-const uschar * p;
-uschar * relaxed = store_get(Ustrlen(header)+3);
+uschar * relaxed = store_get(len+3, GET_TAINTED);
 uschar * q = relaxed;
 
-for (p = header; *p; p++)
+for (const uschar * p = header; p - header < len; p++)
   {
   uschar c = *p;
 
@@ -338,6 +378,13 @@ return relaxed;
 }
 
 
+uschar *
+pdkim_relax_header(const uschar * header, BOOL append_crlf)
+{
+return pdkim_relax_header_n(header, Ustrlen(header), append_crlf);
+}
+
+
 /* -------------------------------------------------------------------------- */
 #define PDKIM_QP_ERROR_DECODE -1
 
@@ -372,7 +419,7 @@ pdkim_decode_qp(const uschar * str)
 int nchar = 0;
 uschar * q;
 const uschar * p = str;
-uschar * n = store_get(Ustrlen(str)+1);
+uschar * n = store_get(Ustrlen(str)+1, GET_TAINTED);
 
 *n = '\0';
 q = n;
@@ -398,19 +445,18 @@ return n;
 
 /* -------------------------------------------------------------------------- */
 
-static void
+void
 pdkim_decode_base64(const uschar * str, blob * b)
 {
-int dlen;
-dlen = b64decode(str, &b->data);
+int dlen = b64decode(str, &b->data, str);
 if (dlen < 0) b->data = NULL;
 b->len = dlen;
 }
 
-static uschar *
+uschar *
 pdkim_encode_base64(blob * b)
 {
-return b64encode(b->data, b->len);
+return b64encode(CUS b->data, b->len);
 }
 
 
@@ -423,15 +469,14 @@ static pdkim_signature *
 pdkim_parse_sig_header(pdkim_ctx * ctx, uschar * raw_hdr)
 {
 pdkim_signature * sig;
-uschar *p, *q;
+uschar *q;
 gstring * cur_tag = NULL;
 gstring * cur_val = NULL;
 BOOL past_hname = FALSE;
 BOOL in_b_val = FALSE;
 int where = PDKIM_HDR_LIMBO;
-int i;
 
-sig = store_get(sizeof(pdkim_signature));
+sig = store_get(sizeof(pdkim_signature), GET_UNTAINTED);
 memset(sig, 0, sizeof(pdkim_signature));
 sig->bodylength = -1;
 
@@ -440,9 +485,9 @@ sig->version = 0;
 sig->keytype = -1;
 sig->hashtype = -1;
 
-q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1);
+q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1, GET_TAINTED);
 
-for (p = raw_hdr; ; p++)
+for (uschar * p = raw_hdr; ; p++)
   {
   char c = *p;
 
@@ -490,7 +535,12 @@ for (p = raw_hdr; ; p++)
 
     if (c == ';' || c == '\0')
       {
-      if (cur_tag && cur_val)
+      /* We must have both tag and value, and tags must be one char except
+      for the possibility of "bh". */
+
+      if (  cur_tag && cur_val
+	 && (cur_tag->ptr == 1 || *cur_tag->s == 'b')
+	 )
         {
 	(void) string_from_gstring(cur_val);
 	pdkim_strtrim(cur_val);
@@ -499,62 +549,66 @@ for (p = raw_hdr; ; p++)
 
 	switch (*cur_tag->s)
 	  {
-	  case 'b':
-	    pdkim_decode_base64(cur_val->s,
-			    cur_tag->s[1] == 'h' ? &sig->bodyhash : &sig->sighash);
+	  case 'b':				/* sig-data or body-hash */
+	    switch (cur_tag->s[1])
+	      {
+	      case '\0': pdkim_decode_base64(cur_val->s, &sig->sighash); break;
+	      case 'h':  if (cur_tag->ptr == 2)
+			   pdkim_decode_base64(cur_val->s, &sig->bodyhash);
+			 break;
+	      default:   break;
+	      }
 	    break;
-	  case 'v':
+	  case 'v':					/* version */
 	      /* We only support version 1, and that is currently the
 		 only version there is. */
 	    sig->version =
 	      Ustrcmp(cur_val->s, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1;
 	    break;
-	  case 'a':
+	  case 'a':					/* algorithm */
 	    {
-	    uschar * s = Ustrchr(cur_val->s, '-');
-
-	    for(i = 0; i < nelem(pdkim_keytypes); i++)
-	      if (Ustrncmp(cur_val->s, pdkim_keytypes[i], s - cur_val->s) == 0)
-		{ sig->keytype = i; break; }
-	    for (++s, i = 0; i < nelem(pdkim_hashes); i++)
-	      if (Ustrcmp(s, pdkim_hashes[i].dkim_hashname) == 0)
-		{ sig->hashtype = i; break; }
-	    break;
+	    const uschar * list = cur_val->s;
+	    int sep = '-';
+	    uschar * elem;
+
+	    if ((elem = string_nextinlist(&list, &sep, NULL, 0)))
+	      sig->keytype = pdkim_keyname_to_keytype(elem);
+	    if ((elem = string_nextinlist(&list, &sep, NULL, 0)))
+	      for (int i = 0; i < nelem(pdkim_hashes); i++)
+		if (Ustrcmp(elem, pdkim_hashes[i].dkim_hashname) == 0)
+		  { sig->hashtype = i; break; }
 	    }
 
-	  case 'c':
-	    for (i = 0; pdkim_combined_canons[i].str; i++)
-	      if (Ustrcmp(cur_val->s, pdkim_combined_canons[i].str) == 0)
-	        {
-		sig->canon_headers = pdkim_combined_canons[i].canon_headers;
-		sig->canon_body    = pdkim_combined_canons[i].canon_body;
-		break;
-		}
+	  case 'c':					/* canonicalization */
+	    pdkim_cstring_to_canons(cur_val->s, 0,
+				    &sig->canon_headers, &sig->canon_body);
 	    break;
-	  case 'q':
-	    for (i = 0; pdkim_querymethods[i]; i++)
+	  case 'q':				/* Query method (for pubkey)*/
+	    for (int i = 0; pdkim_querymethods[i]; i++)
 	      if (Ustrcmp(cur_val->s, pdkim_querymethods[i]) == 0)
 	        {
-		sig->querymethod = i;
+		sig->querymethod = i;	/* we never actually use this */
 		break;
 		}
 	    break;
-	  case 's':
+	  case 's':					/* Selector */
 	    sig->selector = string_copyn(cur_val->s, cur_val->ptr); break;
-	  case 'd':
+	  case 'd':					/* SDID */
 	    sig->domain = string_copyn(cur_val->s, cur_val->ptr); break;
-	  case 'i':
+	  case 'i':					/* AUID */
 	    sig->identity = pdkim_decode_qp(cur_val->s); break;
-	  case 't':
+	  case 't':					/* Timestamp */
 	    sig->created = strtoul(CS cur_val->s, NULL, 10); break;
-	  case 'x':
+	  case 'x':					/* Expiration */
 	    sig->expires = strtoul(CS cur_val->s, NULL, 10); break;
-	  case 'l':
+	  case 'l':					/* Body length count */
 	    sig->bodylength = strtol(CS cur_val->s, NULL, 10); break;
-	  case 'h':
+	  case 'h':					/* signed header fields */
 	    sig->headernames = string_copyn(cur_val->s, cur_val->ptr); break;
-	  case 'z':
+	  case 'z':					/* Copied headfields */
 	    sig->copiedheaders = pdkim_decode_qp(cur_val->s); break;
+/*XXX draft-ietf-dcrup-dkim-crypto-05 would need 'p' tag support
+for rsafp signatures.  But later discussion is dropping those. */
 	  default:
 	    DEBUG(D_acl) debug_printf(" Unknown tag encountered\n");
 	    break;
@@ -576,6 +630,9 @@ NEXT_CHAR:
     *q++ = c;
   }
 
+if (sig->keytype < 0 || sig->hashtype < 0)	/* Cannot verify this signature */
+  return NULL;
+
 *q = '\0';
 /* Chomp raw header. The final newline must not be added to the signature. */
 while (--q > sig->rawsig_no_b_val  && (*q == '\r' || *q == '\n'))
@@ -584,36 +641,31 @@ while (--q > sig->rawsig_no_b_val  && (*q == '\r' || *q == '\n'))
 DEBUG(D_acl)
   {
   debug_printf(
-	  "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+	  "DKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
   pdkim_quoteprint(US sig->rawsig_no_b_val, Ustrlen(sig->rawsig_no_b_val));
   debug_printf(
-	  "PDKIM >> Sig size: %4u bits\n", (unsigned) sig->sighash.len*8);
+	  "DKIM >> Sig size: %4u bits\n", (unsigned) sig->sighash.len*8);
   debug_printf(
-	  "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+	  "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
   }
 
-/*XXX hash method: extend for sha512 */
-if (!exim_sha_init(&sig->body_hash_ctx,
-	       pdkim_hashes[sig->hashtype].exim_hashmethod))
-  {
-  DEBUG(D_acl)
-    debug_printf("PDKIM: hash init error, possibly nonhandled hashtype\n");
+if (!pdkim_set_sig_bodyhash(ctx, sig))
   return NULL;
-  }
+
 return sig;
 }
 
 
 /* -------------------------------------------------------------------------- */
 
-static pdkim_pubkey *
-pdkim_parse_pubkey_record(pdkim_ctx *ctx, const uschar *raw_record)
+pdkim_pubkey *
+pdkim_parse_pubkey_record(const uschar *raw_record)
 {
 const uschar * ele;
 int sep = ';';
 pdkim_pubkey * pub;
 
-pub = store_get(sizeof(pdkim_pubkey));
+pub = store_get(sizeof(pdkim_pubkey), GET_TAINTED);
 memset(pub, 0, sizeof(pdkim_pubkey));
 
 while ((ele = string_nextinlist(&raw_record, &sep, NULL, 0)))
@@ -629,7 +681,7 @@ while ((ele = string_nextinlist(&raw_record, &sep, NULL, 0)))
       {
       case 'v': pub->version = val;			break;
       case 'h': pub->hashes = val;			break;
-      case 'k': break;
+      case 'k': pub->keytype = val;			break;
       case 'g': pub->granularity = val;			break;
       case 'n': pub->notes = pdkim_decode_qp(val);	break;
       case 'p': pdkim_decode_base64(val, &pub->key);	break;
@@ -643,7 +695,8 @@ while ((ele = string_nextinlist(&raw_record, &sep, NULL, 0)))
   }
 
 /* Set fallback defaults */
-if (!pub->version    ) pub->version     = string_copy(PDKIM_PUB_RECORD_VERSION);
+if (!pub->version)
+  pub->version = string_copy(PDKIM_PUB_RECORD_VERSION);
 else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0)
   {
   DEBUG(D_acl) debug_printf(" Bad v= field\n");
@@ -651,9 +704,7 @@ else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0)
   }
 
 if (!pub->granularity) pub->granularity = US"*";
-/*
 if (!pub->keytype    ) pub->keytype     = US"rsa";
-*/
 if (!pub->srvtype    ) pub->srvtype     = US"*";
 
 /* p= is required */
@@ -667,29 +718,23 @@ return NULL;
 
 /* -------------------------------------------------------------------------- */
 
-/* Update the bodyhash for one sig, with some additional data.
+/* Update one bodyhash with some additional data.
 If we have to relax the data for this sig, return our copy of it. */
 
-/*XXX Currently we calculate a hash for each sig.  But it is possible
-that multi-signing will be wanted using different signing algos
-(rsa, ec) using the same hash and canonicalization.  Consider in future
-hanging the hash+cacnon from the ctx and only referencing from the sig,
-so that it can be calculated only once - being over the body this
-caould be meagbytes, hence expensive. */
-
 static blob *
-pdkim_update_sig_bodyhash(pdkim_signature * sig, blob * orig_data, blob * relaxed_data)
+pdkim_update_ctx_bodyhash(pdkim_bodyhash * b, const blob * orig_data, blob * relaxed_data)
 {
-blob * canon_data = orig_data;
+const blob * canon_data = orig_data;
+size_t left;
+
 /* Defaults to simple canon (no further treatment necessary) */
 
-if (sig->canon_body == PDKIM_CANON_RELAXED)
+if (b->canon_method == PDKIM_CANON_RELAXED)
   {
   /* Relax the line if not done already */
   if (!relaxed_data)
     {
     BOOL seen_wsp = FALSE;
-    const uschar * p;
     int q = 0;
 
     /* We want to be able to free this else we allocate
@@ -700,7 +745,7 @@ if (sig->canon_body == PDKIM_CANON_RELAXED)
     relaxed_data = store_malloc(sizeof(blob) + orig_data->len+1);
     relaxed_data->data = US (relaxed_data+1);
 
-    for (p = orig_data->data; *p; p++)
+    for (const uschar * p = orig_data->data, * r = p + orig_data->len; p < r; p++)
       {
       char c = *p;
       if (c == '\r')
@@ -726,16 +771,17 @@ if (sig->canon_body == PDKIM_CANON_RELAXED)
   }
 
 /* Make sure we don't exceed the to-be-signed body length */
-if (  sig->bodylength >= 0
-   && sig->signed_body_bytes + (unsigned long)canon_data->len > sig->bodylength
+left = canon_data->len;
+if (  b->bodylength >= 0
+   && left > (unsigned long)b->bodylength - b->signed_body_bytes
    )
-  canon_data->len = sig->bodylength - sig->signed_body_bytes;
+  left = (unsigned long)b->bodylength - b->signed_body_bytes;
 
-if (canon_data->len > 0)
+if (left > 0)
   {
-  exim_sha_update(&sig->body_hash_ctx, CUS canon_data->data, canon_data->len);
-  sig->signed_body_bytes += canon_data->len;
-  DEBUG(D_acl) pdkim_quoteprint(canon_data->data, canon_data->len);
+  exim_sha_update(&b->body_hash_ctx, CUS canon_data->data, left);
+  b->signed_body_bytes += left;
+  DEBUG(D_acl) pdkim_quoteprint(canon_data->data, left);
   }
 
 return relaxed_data;
@@ -747,32 +793,34 @@ return relaxed_data;
 static void
 pdkim_finish_bodyhash(pdkim_ctx * ctx)
 {
-pdkim_signature * sig;
+for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next)     /* Finish hashes */
+  {
+  DEBUG(D_acl) debug_printf("DKIM: finish bodyhash %s/%s/%ld len %ld\n",
+      pdkim_hashes[b->hashtype].dkim_hashname, pdkim_canons[b->canon_method],
+      b->bodylength, b->signed_body_bytes);
+  exim_sha_finish(&b->body_hash_ctx, &b->bh);
+  }
 
 /* Traverse all signatures */
-for (sig = ctx->sig; sig; sig = sig->next)
-  {					/* Finish hashes */
-  blob bh;
-
-  exim_sha_finish(&sig->body_hash_ctx, &bh);
+for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next)
+  {
+  pdkim_bodyhash * b = sig->calc_body_hash;
 
   DEBUG(D_acl)
     {
-    debug_printf("PDKIM [%s] Body bytes hashed: %lu\n"
-		 "PDKIM [%s] Body %s computed: ",
-		sig->domain, sig->signed_body_bytes,
-		sig->domain, pdkim_hashes[sig->hashtype].dkim_hashname);
-    pdkim_hexprint(CUS bh.data, bh.len);
+    debug_printf("DKIM [%s]%s Body bytes (%s) hashed: %lu\n"
+		 "DKIM [%s]%s Body %s computed: ",
+	sig->domain, sig->selector, pdkim_canons[b->canon_method], b->signed_body_bytes,
+	sig->domain, sig->selector, pdkim_hashes[b->hashtype].dkim_hashname);
+    pdkim_hexprint(CUS b->bh.data, b->bh.len);
     }
 
   /* SIGNING -------------------------------------------------------------- */
   if (ctx->flags & PDKIM_MODE_SIGN)
     {
-    sig->bodyhash = bh;
-
     /* If bodylength limit is set, and we have received less bytes
        than the requested amount, effectively remove the limit tag. */
-    if (sig->signed_body_bytes < sig->bodylength)
+    if (b->signed_body_bytes < sig->bodylength)
       sig->bodylength = -1;
     }
 
@@ -780,17 +828,18 @@ for (sig = ctx->sig; sig; sig = sig->next)
   /* VERIFICATION --------------------------------------------------------- */
   /* Be careful that the header sig included a bodyash */
 
-    if (sig->bodyhash.data && memcmp(bh.data, sig->bodyhash.data, bh.len) == 0)
+    if (sig->bodyhash.data && sig->bodyhash.len == b->bh.len
+       && memcmp(b->bh.data, sig->bodyhash.data, b->bh.len) == 0)
       {
-      DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash verified OK\n", sig->domain);
+      DEBUG(D_acl) debug_printf("DKIM [%s] Body hash compared OK\n", sig->domain);
       }
     else
       {
       DEBUG(D_acl)
         {
-	debug_printf("PDKIM [%s] Body hash signature from headers: ", sig->domain);
+	debug_printf("DKIM [%s] Body hash signature from headers: ", sig->domain);
 	pdkim_hexprint(sig->bodyhash.data, sig->bodyhash.len);
-	debug_printf("PDKIM [%s] Body hash did NOT verify\n", sig->domain);
+	debug_printf("DKIM [%s] Body hash did NOT verify\n", sig->domain);
 	}
       sig->verify_status     = PDKIM_VERIFY_FAIL;
       sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY;
@@ -803,20 +852,18 @@ for (sig = ctx->sig; sig; sig = sig->next)
 static void
 pdkim_body_complete(pdkim_ctx * ctx)
 {
-pdkim_signature * sig;
-
 /* In simple body mode, if any empty lines were buffered,
 replace with one. rfc 4871 3.4.3 */
 /*XXX checking the signed-body-bytes is a gross hack; I think
 it indicates that all linebreaks should be buffered, including
 the one terminating a text line */
 
-for (sig = ctx->sig; sig; sig = sig->next)
-  if (  sig->canon_body == PDKIM_CANON_SIMPLE
-     && sig->signed_body_bytes == 0
-     && sig->num_buffered_blanklines > 0
+for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next)
+  if (  b->canon_method == PDKIM_CANON_SIMPLE
+     && b->signed_body_bytes == 0
+     && b->num_buffered_blanklines > 0
      )
-    (void) pdkim_update_sig_bodyhash(sig, &lineending, NULL);
+    (void) pdkim_update_ctx_bodyhash(b, &lineending, NULL);
 
 ctx->flags |= PDKIM_SEEN_EOD;
 ctx->linebuf_offset = 0;
@@ -826,12 +873,12 @@ ctx->linebuf_offset = 0;
 
 /* -------------------------------------------------------------------------- */
 /* Call from pdkim_feed below for processing complete body lines */
+/* NOTE: the line is not NUL-terminated; but we have a count */
 
 static void
 pdkim_bodyline_complete(pdkim_ctx * ctx)
 {
 blob line = {.data = ctx->linebuf, .len = ctx->linebuf_offset};
-pdkim_signature * sig;
 blob * rnl = NULL;
 blob * rline = NULL;
 
@@ -855,14 +902,15 @@ if (ctx->flags & PDKIM_DOT_TERM)
 /* Empty lines need to be buffered until we find a non-empty line */
 if (memcmp(line.data, "\r\n", 2) == 0)
   {
-  for (sig = ctx->sig; sig; sig = sig->next) sig->num_buffered_blanklines++;
+  for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next)
+    b->num_buffered_blanklines++;
   goto all_skip;
   }
 
-/* Process line for each sig separately */
-for (sig = ctx->sig; sig; sig = sig->next)
+/* Process line for each bodyhash separately */
+for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next)
   {
-  if (sig->canon_body == PDKIM_CANON_RELAXED)
+  if (b->canon_method == PDKIM_CANON_RELAXED)
     {
     /* Lines with just spaces need to be buffered too */
     uschar * cp = line.data;
@@ -871,25 +919,25 @@ for (sig = ctx->sig; sig; sig = sig->next)
     while ((c = *cp))
       {
       if (c == '\r' && cp[1] == '\n') break;
-      if (c != ' ' && c != '\t') goto sig_process;
+      if (c != ' ' && c != '\t') goto hash_process;
       cp++;
       }
 
-    sig->num_buffered_blanklines++;
-    goto sig_skip;
+    b->num_buffered_blanklines++;
+    goto hash_skip;
     }
 
-sig_process:
+hash_process:
   /* At this point, we have a non-empty line, so release the buffered ones. */
 
-  while (sig->num_buffered_blanklines)
+  while (b->num_buffered_blanklines)
     {
-    rnl = pdkim_update_sig_bodyhash(sig, &lineending, rnl);
-    sig->num_buffered_blanklines--;
+    rnl = pdkim_update_ctx_bodyhash(b, &lineending, rnl);
+    b->num_buffered_blanklines--;
     }
 
-  rline = pdkim_update_sig_bodyhash(sig, &line, rline);
-sig_skip: ;
+  rline = pdkim_update_ctx_bodyhash(b, &line, rline);
+hash_skip: ;
   }
 
 if (rnl) store_free(rnl);
@@ -909,19 +957,20 @@ return;
 static int
 pdkim_header_complete(pdkim_ctx * ctx)
 {
-pdkim_signature * sig, * last_sig;
-
-/* Special case: The last header can have an extra \r appended */
-if ( (ctx->cur_header->ptr > 1) &&
-     (ctx->cur_header->s[ctx->cur_header->ptr-1] == '\r') )
-  --ctx->cur_header->ptr;
+if (ctx->cur_header->ptr > 1)
+  gstring_trim_trailing(ctx->cur_header, '\r');
 (void) string_from_gstring(ctx->cur_header);
 
+#ifdef EXPERIMENTAL_ARC
+/* Feed the header line to ARC processing */
+(void) arc_header_feed(ctx->cur_header, !(ctx->flags & PDKIM_MODE_SIGN));
+#endif
+
 if (++ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL;
 
 /* SIGNING -------------------------------------------------------------- */
 if (ctx->flags & PDKIM_MODE_SIGN)
-  for (sig = ctx->sig; sig; sig = sig->next)			/* Traverse all signatures */
+  for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next)  /* Traverse all signatures */
 
     /* Add header to the signed headers list (in reverse order) */
     sig->headers = pdkim_prepend_stringlist(sig->headers, ctx->cur_header->s);
@@ -933,7 +982,7 @@ else
 #ifdef notdef
   DEBUG(D_acl)
     {
-    debug_printf("PDKIM >> raw hdr: ");
+    debug_printf("DKIM >> raw hdr: ");
     pdkim_quoteprint(CUS ctx->cur_header->s, ctx->cur_header->ptr);
     }
 #endif
@@ -941,12 +990,13 @@ else
 		  DKIM_SIGNATURE_HEADERNAME,
 		  Ustrlen(DKIM_SIGNATURE_HEADERNAME)) == 0)
     {
+    pdkim_signature * sig, * last_sig;
     /* Create and chain new signature block.  We could error-check for all
     required tags here, but prefer to create the internal sig and expicitly
     fail verification of it later. */
 
     DEBUG(D_acl) debug_printf(
-	"PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+	"DKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
 
     sig = pdkim_parse_sig_header(ctx, ctx->cur_header->s);
 
@@ -957,6 +1007,13 @@ else
       while (last_sig->next) last_sig = last_sig->next;
       last_sig->next = sig;
       }
+
+    if (dkim_collect_input && --dkim_collect_input == 0)
+      {
+      ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->s);
+      ctx->cur_header->s[ctx->cur_header->ptr = 0] = '\0';
+      return PDKIM_ERR_EXCESS_SIGS;
+      }
     }
 
   /* all headers are stored for signature verification */
@@ -976,15 +1033,14 @@ return PDKIM_OK;
 DLLEXPORT int
 pdkim_feed(pdkim_ctx * ctx, uschar * data, int len)
 {
-int p, rc;
-
 /* Alternate EOD signal, used in non-dotstuffing mode */
 if (!data)
   pdkim_body_complete(ctx);
 
-else for (p = 0; p<len; p++)
+else for (int p = 0; p < len; p++)
   {
   uschar c = data[p];
+  int rc;
 
   if (ctx->flags & PDKIM_PAST_HDRS)
     {
@@ -1025,7 +1081,7 @@ else for (p = 0; p<len; p++)
 
 	ctx->flags = (ctx->flags & ~(PDKIM_SEEN_LF|PDKIM_SEEN_CR)) | PDKIM_PAST_HDRS;
 	DEBUG(D_acl) debug_printf(
-	    "PDKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+	    "DKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
 	continue;
 	}
       else
@@ -1060,14 +1116,14 @@ return string_catn(str, US"\r\n\t", 3);
 
 /*
  * RFC 5322 specifies that header line length SHOULD be no more than 78
- * lets make it so!
  *  pdkim_headcat
  *
- * returns uschar * (not nul-terminated)
+ * Returns gstring (not nul-terminated) appending to one supplied
  *
  * col: this int holds and receives column number (octets since last '\n')
  * str: partial string to append to
- * pad: padding, split line or space after before or after eg: ";"
+ * pad: padding, split line or space after before or after eg: ";".
+ *               Only the initial charater is used.
  * intro: - must join to payload eg "h=", usually the tag name
  * payload: eg base64 data - long data can be split arbitrarily.
  *
@@ -1076,7 +1132,7 @@ return string_catn(str, US"\r\n\t", 3);
  * pairs and inside long values. it also always spaces or breaks after the
  * "pad"
  *
- * no guarantees are made for output given out-of range input. like tag
+ * No guarantees are made for output given out-of range input. like tag
  * names longer than 78, or bogus col. Input is assumed to be free of line breaks.
  */
 
@@ -1084,92 +1140,64 @@ static gstring *
 pdkim_headcat(int * col, gstring * str,
   const uschar * pad, const uschar * intro, const uschar * payload)
 {
-size_t l;
+int len, chomp, padded = 0;
 
-if (pad)
-  {
-  l = Ustrlen(pad);
-  if (*col + l > 78)
-    str = pdkim_hdr_cont(str, col);
-  str = string_catn(str, pad, l);
-  *col += l;
-  }
-
-l = (pad?1:0) + (intro?Ustrlen(intro):0);
-
-if (*col + l > 78)
-  { /*can't fit intro - start a new line to make room.*/
-  str = pdkim_hdr_cont(str, col);
-  l = intro?Ustrlen(intro):0;
-  }
-
-l += payload ? Ustrlen(payload):0 ;
-
-while (l>77)
-  { /* this fragment will not fit on a single line */
-  if (pad)
-    {
-    str = string_catn(str, US" ", 1);
-    *col += 1;
-    pad = NULL; /* only want this once */
-    l--;
-    }
-
-  if (intro)
-    {
-    size_t sl = Ustrlen(intro);
+/* If we can fit at least the pad at the end of current line, do it now.
+Otherwise, wrap if there is a pad. */
 
-    str = string_catn(str, intro, sl);
-    *col += sl;
-    l -= sl;
-    intro = NULL; /* only want this once */
-    }
-
-  if (payload)
+if (pad)
+  if (*col + 1 <= 78)
     {
-    size_t sl = Ustrlen(payload);
-    size_t chomp = *col+sl < 77 ? sl : 78-*col;
-
-    str = string_catn(str, payload, chomp);
-    *col += chomp;
-    payload += chomp;
-    l -= chomp-1;
+    str = string_catn(str, pad, 1);
+    (*col)++;
+    pad = NULL;
+    padded = 1;
     }
+  else
+    str = pdkim_hdr_cont(str, col);
 
-  /* the while precondition tells us it didn't fit. */
-  str = pdkim_hdr_cont(str, col);
-  }
+/* Special case: if the whole addition does not fit at the end of the current
+line, but could fit on a new line, wrap to give it its full, dedicated line.  */
 
-if (*col + l > 78)
+len = (pad ? 2 : padded)
+    + (intro ? Ustrlen(intro) : 0)
+    + (payload ? Ustrlen(payload) : 0);
+if (len <= 77 && *col+len > 78)
   {
   str = pdkim_hdr_cont(str, col);
-  pad = NULL;
+  padded = 0;
   }
 
+/* Either we already dealt with the pad or we know there is room */
+
 if (pad)
   {
+  str = string_catn(str, pad, 1);
   str = string_catn(str, US" ", 1);
-  *col += 1;
-  pad = NULL;
+  *col += 2;
   }
-
-if (intro)
+else if (padded && *col < 78)
   {
-  size_t sl = Ustrlen(intro);
-
-  str = string_catn(str, intro, sl);
-  *col += sl;
-  l -= sl;
-  intro = NULL;
+  str = string_catn(str, US" ", 1);
+  (*col)++;
   }
 
-if (payload)
-  {
-  size_t sl = Ustrlen(payload);
+/* Call recursively with intro as payload: it gets the same, special treatment
+(that is, not split if < 78).  */
 
-  str = string_catn(str, payload, sl);
-  *col += sl;
-  }
+if (intro)
+  str = pdkim_headcat(col, str, NULL, NULL, intro);
+
+if (payload)
+  for (len = Ustrlen(payload); len; len -= chomp)
+    {
+    if (*col >= 78)
+      str = pdkim_hdr_cont(str, col);
+    chomp = *col+len > 78 ? 78 - *col : len;
+    str = string_catn(str, payload, chomp);
+    *col += chomp;
+    payload += chomp;
+    }
 
 return str;
 }
@@ -1177,6 +1205,8 @@ return str;
 
 /* -------------------------------------------------------------------------- */
 
+/* Signing: create signature header
+*/
 static uschar *
 pdkim_create_header(pdkim_signature * sig, BOOL final)
 {
@@ -1227,7 +1257,7 @@ hdr = pdkim_headcat(&col, hdr, US";", US"s=", sig->selector);
     }
   }
 
-base64_bh = pdkim_encode_base64(&sig->bodyhash);
+base64_bh = pdkim_encode_base64(&sig->calc_body_hash->bh);
 hdr = pdkim_headcat(&col, hdr, US";", US"bh=", base64_bh);
 
 /* Optional bits */
@@ -1236,7 +1266,7 @@ if (sig->identity)
 
 if (sig->created > 0)
   {
-  uschar minibuf[20];
+  uschar minibuf[21];
 
   snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created);
   hdr = pdkim_headcat(&col, hdr, US";", US"t=", minibuf);
@@ -1244,7 +1274,7 @@ if (sig->created > 0)
 
 if (sig->expires > 0)
   {
-  uschar minibuf[20];
+  uschar minibuf[21];
 
   snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->expires);
   hdr = pdkim_headcat(&col, hdr, US";", US"x=", minibuf);
@@ -1252,7 +1282,7 @@ if (sig->expires > 0)
 
 if (sig->bodylength >= 0)
   {
-  uschar minibuf[20];
+  uschar minibuf[21];
 
   snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength);
   hdr = pdkim_headcat(&col, hdr, US";", US"l=", minibuf);
@@ -1283,6 +1313,29 @@ return string_from_gstring(hdr);
 
 /* -------------------------------------------------------------------------- */
 
+/* According to draft-ietf-dcrup-dkim-crypto-07 "keys are 256 bits" (referring
+to DNS, hence the pubkey).  Check for more than 32 bytes; if so assume the
+alternate possible representation (still) being discussed: a
+SubjectPublickeyInfo wrapped key - and drop all but the trailing 32-bytes (it
+should be a DER, with exactly 12 leading bytes - but we could accept a BER also,
+which could be any size).  We still rely on the crypto library for checking for
+undersize.
+
+When the RFC is published this should be re-addressed. */
+
+static void
+check_bare_ed25519_pubkey(pdkim_pubkey * p)
+{
+int excess = p->key.len - 32;
+if (excess > 0)
+  {
+  DEBUG(D_acl)
+    debug_printf("DKIM: unexpected pubkey len %lu\n", (unsigned long) p->key.len);
+  p->key.data += excess; p->key.len = 32;
+  }
+}
+
+
 static pdkim_pubkey *
 pdkim_key_from_dns(pdkim_ctx * ctx, pdkim_signature * sig, ev_ctx * vctx,
   const uschar ** errstr)
@@ -1294,10 +1347,7 @@ pdkim_pubkey * p;
 
 dns_txt_name = string_sprintf("%s._domainkey.%s.", sig->selector, sig->domain);
 
-dns_txt_reply = store_get(PDKIM_DNS_TXT_MAX_RECLEN);
-memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN);
-
-if (  ctx->dns_txt_callback(CS dns_txt_name, CS dns_txt_reply) != PDKIM_OK 
+if (  !(dns_txt_reply = ctx->dns_txt_callback(dns_txt_name))
    || dns_txt_reply[0] == '\0'
    )
   {
@@ -1309,14 +1359,14 @@ if (  ctx->dns_txt_callback(CS dns_txt_name, CS dns_txt_reply) != PDKIM_OK
 DEBUG(D_acl)
   {
   debug_printf(
-    "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"
+    "DKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"
     " %s\n"
     " Raw record: ",
     dns_txt_name);
   pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply));
   }
 
-if (  !(p = pdkim_parse_pubkey_record(ctx, CUS dns_txt_reply))
+if (  !(p = pdkim_parse_pubkey_record(CUS dns_txt_reply))
    || (Ustrcmp(p->srvtype, "*") != 0 && Ustrcmp(p->srvtype, "email") != 0)
    )
   {
@@ -1330,16 +1380,36 @@ if (  !(p = pdkim_parse_pubkey_record(ctx, CUS dns_txt_reply))
     else
       debug_printf(" Error while parsing public key record\n");
     debug_printf(
-      "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+      "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
     }
   return NULL;
   }
 
 DEBUG(D_acl) debug_printf(
-      "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+      "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
 
 /* Import public key */
-if ((*errstr = exim_dkim_verify_init(&p->key, vctx)))
+
+/* Normally we use the signature a= tag to tell us the pubkey format.
+When signing under debug we do a test-import of the pubkey, and at that
+time we do not have a signature so we must interpret the pubkey k= tag
+instead.  Assume writing on the sig is ok in that case. */
+
+if (sig->keytype < 0)
+  if ((sig->keytype = pdkim_keyname_to_keytype(p->keytype)) < 0)
+    {
+    DEBUG(D_acl) debug_printf("verify_init: unhandled keytype %s\n", p->keytype);
+    sig->verify_status =      PDKIM_VERIFY_INVALID;
+    sig->verify_ext_status =  PDKIM_VERIFY_INVALID_PUBKEY_IMPORT;
+    return NULL;
+    }
+
+if (sig->keytype == KEYTYPE_ED25519)
+  check_bare_ed25519_pubkey(p);
+
+if ((*errstr = exim_dkim_verify_init(&p->key,
+	    sig->keytype == KEYTYPE_ED25519 ? KEYFMT_ED25519_BARE : KEYFMT_DER,
+	    vctx, &sig->keybits)))
   {
   DEBUG(D_acl) debug_printf("verify_init: %s\n", *errstr);
   sig->verify_status =      PDKIM_VERIFY_INVALID;
@@ -1347,17 +1417,73 @@ if ((*errstr = exim_dkim_verify_init(&p->key, vctx)))
   return NULL;
   }
 
+vctx->keytype = sig->keytype;
 return p;
 }
 
 
+/* -------------------------------------------------------------------------- */
+/* Sort and filter the sigs developed from the message */
+
+static pdkim_signature *
+sort_sig_methods(pdkim_signature * siglist)
+{
+pdkim_signature * yield, ** ss;
+const uschar * prefs;
+uschar * ele;
+int sep;
+
+if (!siglist) return NULL;
+
+/* first select in order of hashtypes */
+DEBUG(D_acl) debug_printf("DKIM: dkim_verify_hashes   '%s'\n", dkim_verify_hashes);
+for (prefs = dkim_verify_hashes, sep = 0, yield = NULL, ss = &yield;
+     ele = string_nextinlist(&prefs, &sep, NULL, 0); )
+  {
+  int i = pdkim_hashname_to_hashtype(CUS ele, 0);
+  for (pdkim_signature * s = siglist, * next, ** prev = &siglist; s;
+       s = next)
+    {
+    next = s->next;
+    if (s->hashtype == i)
+      { *prev = next; s->next = NULL; *ss = s; ss = &s->next; }
+    else
+      prev = &s->next;
+    }
+  }
+
+/* then in order of keytypes */
+siglist = yield;
+DEBUG(D_acl) debug_printf("DKIM: dkim_verify_keytypes '%s'\n", dkim_verify_keytypes);
+for (prefs = dkim_verify_keytypes, sep = 0, yield = NULL, ss = &yield;
+     ele = string_nextinlist(&prefs, &sep, NULL, 0); )
+  {
+  int i = pdkim_keyname_to_keytype(CUS ele);
+  for (pdkim_signature * s = siglist, * next, ** prev = &siglist; s;
+       s = next)
+    {
+    next = s->next;
+    if (s->keytype == i)
+      { *prev = next; s->next = NULL; *ss = s; ss = &s->next; }
+    else
+      prev = &s->next;
+    }
+  }
+
+DEBUG(D_acl) for (pdkim_signature * s = yield; s; s = s->next)
+  debug_printf(" retain d=%s s=%s a=%s\n",
+    s->domain, s->selector, dkim_sig_to_a_tag(s));
+return yield;
+}
+
+
 /* -------------------------------------------------------------------------- */
 
 DLLEXPORT int
 pdkim_feed_finish(pdkim_ctx * ctx, pdkim_signature ** return_signatures,
   const uschar ** err)
 {
-pdkim_signature * sig;
+BOOL verify_pass = FALSE;
 
 /* Check if we must still flush a (partial) header. If that is the
    case, the message has no body, and we must compute a body hash
@@ -1370,39 +1496,84 @@ if (ctx->cur_header && ctx->cur_header->ptr > 0)
   if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK)
     return rc;
 
-  for (sig = ctx->sig; sig; sig = sig->next)
-    rnl = pdkim_update_sig_bodyhash(sig, &lineending, rnl);
+  for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next)
+    rnl = pdkim_update_ctx_bodyhash(b, &lineending, rnl);
   if (rnl) store_free(rnl);
   }
 else
   DEBUG(D_acl) debug_printf(
-      "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+      "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+
+/* Build (and/or evaluate) body hash.  Do this even if no DKIM sigs, in case we
+have a hash to do for ARC. */
 
-/* Build (and/or evaluate) body hash */
 pdkim_finish_bodyhash(ctx);
 
-for (sig = ctx->sig; sig; sig = sig->next)
+/* Sort and filter the recived signatures */
+
+if (!(ctx->flags & PDKIM_MODE_SIGN))
+  ctx->sig = sort_sig_methods(ctx->sig);
+
+if (!ctx->sig)
+  {
+  DEBUG(D_acl) debug_printf("DKIM: no signatures\n");
+  *return_signatures = NULL;
+  return PDKIM_OK;
+  }
+
+for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next)
   {
   hctx hhash_ctx;
   uschar * sig_hdr = US"";
   blob hhash;
   gstring * hdata = NULL;
+  es_ctx sctx;
 
-  if (!exim_sha_init(&hhash_ctx, pdkim_hashes[sig->hashtype].exim_hashmethod))
+  if (  !(ctx->flags & PDKIM_MODE_SIGN)
+     && sig->verify_status == PDKIM_VERIFY_FAIL)
     {
     DEBUG(D_acl)
-      debug_printf("PDKIM: hash setup error, possibly nonhandled hashtype\n");
+       debug_printf("DKIM: [%s] abandoning this signature\n", sig->domain);
+    continue;
+    }
+
+  /*XXX The hash of the headers is needed for GCrypt (for which we can do RSA
+  signing only, as it happens) and for either GnuTLS and OpenSSL when we are
+  signing with EC (specifically, Ed25519).  The former is because the GCrypt
+  signing operation is pure (does not do its own hash) so we must hash.  The
+  latter is because we (stupidly, but this is what the IETF draft is saying)
+  must hash with the declared hash method, then pass the result to the library
+  hash-and-sign routine (because that's all the libraries are providing.  And
+  we're stuck with whatever that hidden hash method is, too).  We may as well
+  do this hash incrementally.
+  We don't need the hash we're calculating here for the GnuTLS and OpenSSL
+  cases of RSA signing, since those library routines can do hash-and-sign.
+
+  Some time in the future we could easily avoid doing the hash here for those
+  cases (which will be common for a long while.  We could also change from
+  the current copy-all-the-headers-into-one-block, then call the hash-and-sign
+  implementation  - to a proper incremental one.  Unfortunately, GnuTLS just
+  cannot do incremental - either signing or verification.  Unsure about GCrypt.
+  */
+
+  /*XXX The header hash is also used (so far) by the verify operation */
+
+  if (!exim_sha_init(&hhash_ctx, pdkim_hashes[sig->hashtype].exim_hashmethod))
+    {
+    log_write(0, LOG_MAIN|LOG_PANIC,
+      "DKIM: hash setup error, possibly nonhandled hashtype");
     break;
     }
 
   if (ctx->flags & PDKIM_MODE_SIGN)
     DEBUG(D_acl) debug_printf(
-	"PDKIM >> Headers to be signed:                            >>>>>>>>>>>>\n"
+	"DKIM >> Headers to be signed:                            >>>>>>>>>>>>\n"
 	" %s\n",
 	sig->sign_headers);
 
   DEBUG(D_acl) debug_printf(
-      "PDKIM >> Header data for hash, canonicalized, in sequence >>>>>>>>>>>>\n");
+      "DKIM >> Header data for hash, canonicalized (%-7s), in sequence >>\n",
+	pdkim_canons[sig->canon_headers]);
 
 
   /* SIGNING ---------------------------------------------------------------- */
@@ -1414,14 +1585,22 @@ for (sig = ctx->sig; sig; sig = sig->next)
   if (ctx->flags & PDKIM_MODE_SIGN)
     {
     gstring * g = NULL;
-    pdkim_stringlist *p;
     const uschar * l;
     uschar * s;
     int sep = 0;
 
-    sig->headernames = NULL;		/* Collected signed header names */
+    /* Import private key, including the keytype which we need for building
+    the signature header  */
+
+    if ((*err = exim_dkim_signing_init(CUS sig->privkey, &sctx)))
+      {
+      log_write(0, LOG_MAIN|LOG_PANIC, "signing_init: %s", *err);
+      return PDKIM_ERR_RSA_PRIVKEY;
+      }
+    sig->keytype = sctx.keytype;
 
-    for (p = sig->headers; p; p = p->next)
+    sig->headernames = NULL;			/* Collected signed header names */
+    for (pdkim_stringlist * p = sig->headers; p; p = p->next)
       {
       uschar * rh = p->value;
 
@@ -1434,9 +1613,10 @@ for (sig = ctx->sig; sig; sig = sig->next)
 	  rh = pdkim_relax_header(rh, TRUE);	/* cook header for relaxed canon */
 
 	/* Feed header to the hash algorithm */
-	exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh));
+	exim_sha_update_string(&hhash_ctx, CUS rh);
 
 	/* Remember headers block for signing (when the library cannot do incremental)  */
+	/*XXX we could avoid doing this for all but the GnuTLS/RSA case */
 	hdata = exim_dkim_data_append(hdata, rh);
 
 	DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh));
@@ -1467,12 +1647,11 @@ for (sig = ctx->sig; sig; sig = sig->next)
     {
     uschar * p = sig->headernames;
     uschar * q;
-    pdkim_stringlist * hdrs;
 
     if (p)
       {
       /* clear tags */
-      for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
+      for (pdkim_stringlist * hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
 	hdrs->tag = 0;
 
       p = string_copy(p);
@@ -1482,7 +1661,7 @@ for (sig = ctx->sig; sig; sig = sig->next)
 	  *q = '\0';
 
   /*XXX walk the list of headers in same order as received. */
-	for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
+	for (pdkim_stringlist * hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
 	  if (  hdrs->tag == 0
 	     && strncasecmp(CCS hdrs->value, CCS p, Ustrlen(p)) == 0
 	     && (hdrs->value)[Ustrlen(p)] == ':'
@@ -1495,7 +1674,7 @@ for (sig = ctx->sig; sig; sig = sig->next)
 	      : string_copy(CUS hdrs->value);
 
 	    /* Feed header to the hash algorithm */
-	    exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh));
+	    exim_sha_update_string(&hhash_ctx, CUS rh);
 
 	    DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh));
 	    hdrs->tag = 1;
@@ -1511,15 +1690,15 @@ for (sig = ctx->sig; sig; sig = sig->next)
     }
 
   DEBUG(D_acl) debug_printf(
-	    "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+	    "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
 
   DEBUG(D_acl)
     {
     debug_printf(
-	    "PDKIM >> Signed DKIM-Signature header, pre-canonicalized >>>>>>>>>>>>>\n");
+	    "DKIM >> Signed DKIM-Signature header, pre-canonicalized >>>>>>>>>>>>>\n");
     pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr));
     debug_printf(
-	    "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+	    "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
     }
 
   /* Relax header if necessary */
@@ -1528,20 +1707,20 @@ for (sig = ctx->sig; sig; sig = sig->next)
 
   DEBUG(D_acl)
     {
-    debug_printf(
-	    "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
+    debug_printf("DKIM >> Signed DKIM-Signature header, canonicalized (%-7s) >>>>>>>\n",
+	    pdkim_canons[sig->canon_headers]);
     pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr));
     debug_printf(
-	    "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+	    "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
     }
 
   /* Finalize header hash */
-  exim_sha_update(&hhash_ctx, CUS sig_hdr, Ustrlen(sig_hdr));
+  exim_sha_update_string(&hhash_ctx, CUS sig_hdr);
   exim_sha_finish(&hhash_ctx, &hhash);
 
   DEBUG(D_acl)
     {
-    debug_printf("PDKIM [%s] Header %s computed: ",
+    debug_printf("DKIM [%s] Header %s computed: ",
       sig->domain, pdkim_hashes[sig->hashtype].dkim_hashname);
     pdkim_hexprint(hhash.data, hhash.len);
     }
@@ -1554,37 +1733,34 @@ for (sig = ctx->sig; sig; sig = sig->next)
   /* SIGNING ---------------------------------------------------------------- */
   if (ctx->flags & PDKIM_MODE_SIGN)
     {
-    es_ctx sctx;
-
-    /* Import private key, including the keytype */
-/*XXX extend for non-RSA algos */
-    if ((*err = exim_dkim_signing_init(US sig->privkey, &sctx)))
-      {
-      DEBUG(D_acl) debug_printf("signing_init: %s\n", *err);
-      return PDKIM_ERR_RSA_PRIVKEY;
-      }
+    hashmethod hm = sig->keytype == KEYTYPE_ED25519
+#if defined(SIGN_OPENSSL)
+      ? HASH_NULL
+#else
+      ? HASH_SHA2_512
+#endif
+      : pdkim_hashes[sig->hashtype].exim_hashmethod;
 
-    /* Do signing.  With OpenSSL we are signing the hash of headers just
-    calculated, with GnuTLS we have to sign an entire block of headers
-    (due to available interfaces) and it recalculates the hash internally. */
+#ifdef SIGN_HAVE_ED25519
+    /* For GCrypt, and for EC, we pass the hash-of-headers to the signing
+    routine.  For anything else we just pass the headers. */
 
-#if defined(SIGN_GNUTLS)
-    hhash.data = hdata->s;
-    hhash.len =  hdata->ptr;
+    if (sig->keytype != KEYTYPE_ED25519)
 #endif
+      {
+      hhash.data = hdata->s;
+      hhash.len = hdata->ptr;
+      }
 
-/*XXX extend for non-RSA algos */
-    if ((*err = exim_dkim_sign(&sctx,
-		  pdkim_hashes[sig->hashtype].exim_hashmethod,
-		  &hhash, &sig->sighash)))
+    if ((*err = exim_dkim_sign(&sctx, hm, &hhash, &sig->sighash)))
       {
-      DEBUG(D_acl) debug_printf("signing: %s\n", *err);
+      log_write(0, LOG_MAIN|LOG_PANIC, "signing: %s", *err);
       return PDKIM_ERR_RSA_SIGNING;
       }
 
     DEBUG(D_acl)
       {
-      debug_printf( "PDKIM [%s] b computed: ", sig->domain);
+      debug_printf( "DKIM [%s] b computed: ", sig->domain);
       pdkim_hexprint(sig->sighash.data, sig->sighash.len);
       }
 
@@ -1595,6 +1771,7 @@ for (sig = ctx->sig; sig; sig = sig->next)
   else
     {
     ev_ctx vctx;
+    hashmethod hm;
 
     /* Make sure we have all required signature tags */
     if (!(  sig->domain        && *sig->domain
@@ -1611,8 +1788,16 @@ for (sig = ctx->sig; sig; sig = sig->next)
       sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR;
 
       DEBUG(D_acl) debug_printf(
-	  " Error in DKIM-Signature header: tags missing or invalid\n"
-	  "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+	  " Error in DKIM-Signature header: tags missing or invalid (%s)\n"
+	  "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n",
+	  !(sig->domain && *sig->domain) ? "d="
+	  : !(sig->selector && *sig->selector) ? "s="
+	  : !(sig->headernames && *sig->headernames) ? "h="
+	  : !sig->bodyhash.data ? "bh="
+	  : !sig->sighash.data ? "b="
+	  : sig->keytype < 0 || sig->hashtype < 0 ? "a="
+	  : "v="
+	  );
       goto NEXT_VERIFY;
       }
 
@@ -1624,18 +1809,23 @@ for (sig = ctx->sig; sig; sig = sig->next)
 
       DEBUG(D_acl) debug_printf(
           " Error in DKIM-Signature header: unsupported DKIM version\n"
-          "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+          "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
       goto NEXT_VERIFY;
       }
 
     DEBUG(D_acl)
       {
-      debug_printf( "PDKIM [%s] b from mail: ", sig->domain);
+      debug_printf( "DKIM [%s] b from mail: ", sig->domain);
       pdkim_hexprint(sig->sighash.data, sig->sighash.len);
       }
 
     if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx, err)))
+      {
+      log_write(0, LOG_MAIN, "DKIM: %s%s %s%s [failed key import]",
+	sig->domain   ? "d=" : "", sig->domain   ? sig->domain   : US"",
+	sig->selector ? "s=" : "", sig->selector ? sig->selector : US"");
       goto NEXT_VERIFY;
+      }
 
     /* If the pubkey limits to a list of specific hashes, ignore sigs that
     do not have the hash part of the sig algorithm matching */
@@ -1658,29 +1848,53 @@ for (sig = ctx->sig; sig; sig = sig->next)
 	}
       }
 
+    hm = sig->keytype == KEYTYPE_ED25519
+#if defined(SIGN_OPENSSL)
+      ? HASH_NULL
+#else
+      ? HASH_SHA2_512
+#endif
+      : pdkim_hashes[sig->hashtype].exim_hashmethod;
+
     /* Check the signature */
-/*XXX needs extension for non-RSA */
-    if ((*err = exim_dkim_verify(&vctx,
-		  pdkim_hashes[sig->hashtype].exim_hashmethod,
-		  &hhash, &sig->sighash)))
+
+    if ((*err = exim_dkim_verify(&vctx, hm, &hhash, &sig->sighash)))
       {
       DEBUG(D_acl) debug_printf("headers verify: %s\n", *err);
       sig->verify_status =      PDKIM_VERIFY_FAIL;
       sig->verify_ext_status =  PDKIM_VERIFY_FAIL_MESSAGE;
       goto NEXT_VERIFY;
       }
+    if (*dkim_verify_min_keysizes)
+      {
+      unsigned minbits;
+      uschar * ss = expand_getkeyed(US pdkim_keytypes[sig->keytype],
+				    dkim_verify_min_keysizes);
+      if (ss &&  (minbits = atoi(CS ss)) > sig->keybits)
+	{
+	DEBUG(D_acl) debug_printf("Key too short: Actual: %s %u  Minima '%s'\n",
+	  pdkim_keytypes[sig->keytype], sig->keybits, dkim_verify_min_keysizes);
+	sig->verify_status =      PDKIM_VERIFY_FAIL;
+	sig->verify_ext_status =  PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE;
+	}
+      }
 
 
     /* We have a winner! (if bodyhash was correct earlier) */
     if (sig->verify_status == PDKIM_VERIFY_NONE)
+      {
       sig->verify_status = PDKIM_VERIFY_PASS;
+      verify_pass = TRUE;
+      if (dkim_verify_minimal) break;
+      }
 
 NEXT_VERIFY:
 
     DEBUG(D_acl)
       {
-      debug_printf("PDKIM [%s] signature status: %s",
-	      sig->domain, pdkim_verify_status_str(sig->verify_status));
+      debug_printf("DKIM [%s] %s signature status: %s",
+	      sig->domain, dkim_sig_to_a_tag(sig),
+	      pdkim_verify_status_str(sig->verify_status));
       if (sig->verify_ext_status > 0)
 	debug_printf(" (%s)\n",
 		pdkim_verify_ext_status_str(sig->verify_ext_status));
@@ -1694,23 +1908,26 @@ NEXT_VERIFY:
 if (return_signatures)
   *return_signatures = ctx->sig;
 
-return PDKIM_OK;
+return ctx->flags & PDKIM_MODE_SIGN  ||  verify_pass
+  ? PDKIM_OK : PDKIM_FAIL;
 }
 
 
 /* -------------------------------------------------------------------------- */
 
 DLLEXPORT pdkim_ctx *
-pdkim_init_verify(int(*dns_txt_callback)(char *, char *), BOOL dot_stuffing)
+pdkim_init_verify(uschar * (*dns_txt_callback)(const uschar *), BOOL dot_stuffing)
 {
 pdkim_ctx * ctx;
 
-ctx = store_get(sizeof(pdkim_ctx));
+ctx = store_get(sizeof(pdkim_ctx), GET_UNTAINTED);
 memset(ctx, 0, sizeof(pdkim_ctx));
 
 if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM;
-ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN);
+/* The line-buffer is for message data, hence tainted */
+ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, GET_TAINTED);
 ctx->dns_txt_callback = dns_txt_callback;
+ctx->cur_header = string_get_tainted(36, GET_TAINTED);
 
 return ctx;
 }
@@ -1718,8 +1935,6 @@ return ctx;
 
 /* -------------------------------------------------------------------------- */
 
-/*XXX ? needs extension to cover non-RSA algo?  */
-
 DLLEXPORT pdkim_signature *
 pdkim_init_sign(pdkim_ctx * ctx,
   uschar * domain, uschar * selector, uschar * privkey,
@@ -1733,7 +1948,7 @@ if (!domain || !selector || !privkey)
 
 /* Allocate & init one signature struct */
 
-sig = store_get(sizeof(pdkim_signature));
+sig = store_get(sizeof(pdkim_signature), GET_UNTAINTED);
 memset(sig, 0, sizeof(pdkim_signature));
 
 sig->bodylength = -1;
@@ -1741,22 +1956,15 @@ sig->bodylength = -1;
 sig->domain = string_copy(US domain);
 sig->selector = string_copy(US selector);
 sig->privkey = string_copy(US privkey);
-/*XXX no keytype yet; comes from privkey */
+sig->keytype = -1;
 
 for (hashtype = 0; hashtype < nelem(pdkim_hashes); hashtype++)
   if (Ustrcmp(hashname, pdkim_hashes[hashtype].dkim_hashname) == 0)
   { sig->hashtype = hashtype; break; }
 if (hashtype >= nelem(pdkim_hashes))
   {
-  DEBUG(D_acl)
-    debug_printf("PDKIM: unrecognised hashname '%s'\n", hashname);
-  return NULL;
-  }
-
-if (!exim_sha_init(&sig->body_hash_ctx, pdkim_hashes[hashtype].exim_hashmethod))
-  {
-  DEBUG(D_acl)
-    debug_printf("PDKIM: hash setup error, possibly nonhandled hashtype\n");
+  log_write(0, LOG_MAIN|LOG_PANIC,
+    "DKIM: unrecognised hashname '%s'", hashname);
   return NULL;
   }
 
@@ -1765,10 +1973,10 @@ DEBUG(D_acl)
   pdkim_signature s = *sig;
   ev_ctx vctx;
 
-  debug_printf("PDKIM (checking verify key)>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+  debug_printf("DKIM (checking verify key)>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
   if (!pdkim_key_from_dns(ctx, &s, &vctx, errstr))
     debug_printf("WARNING: bad dkim key in dns\n");
-  debug_printf("PDKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+  debug_printf("DKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
   }
 return sig;
 }
@@ -1803,13 +2011,77 @@ return;
 
 
 
+/* Set up a blob for calculating the bodyhash according to the
+given needs.  Use an existing one if possible, or create a new one.
+
+Return: hashblob pointer, or NULL on error
+*/
+pdkim_bodyhash *
+pdkim_set_bodyhash(pdkim_ctx * ctx, int hashtype, int canon_method,
+	long bodylength)
+{
+pdkim_bodyhash * b;
+
+if (hashtype == -1 || canon_method == -1) return NULL;
+
+for (b = ctx->bodyhash; b; b = b->next)
+  if (  hashtype == b->hashtype
+     && canon_method == b->canon_method
+     && bodylength == b->bodylength)
+    {
+    DEBUG(D_receive) debug_printf("DKIM: using existing bodyhash %s/%s/%ld\n",
+      pdkim_hashes[hashtype].dkim_hashname, pdkim_canons[canon_method], bodylength);
+    return b;
+    }
+
+DEBUG(D_receive) debug_printf("DKIM: new bodyhash %s/%s/%ld\n",
+    pdkim_hashes[hashtype].dkim_hashname, pdkim_canons[canon_method], bodylength);
+b = store_get(sizeof(pdkim_bodyhash), GET_UNTAINTED);
+b->next = ctx->bodyhash;
+b->hashtype = hashtype;
+b->canon_method = canon_method;
+b->bodylength = bodylength;
+if (!exim_sha_init(&b->body_hash_ctx,		/*XXX hash method: extend for sha512 */
+		  pdkim_hashes[hashtype].exim_hashmethod))
+  {
+  DEBUG(D_acl)
+    debug_printf("DKIM: hash init error, possibly nonhandled hashtype\n");
+  return NULL;
+  }
+b->signed_body_bytes = 0;
+b->num_buffered_blanklines = 0;
+ctx->bodyhash = b;
+return b;
+}
+
+
+/* Set up a blob for calculating the bodyhash according to the
+needs of this signature.  Use an existing one if possible, or
+create a new one.
+
+Return: hashblob pointer, or NULL on error (only used as a boolean).
+*/
+pdkim_bodyhash *
+pdkim_set_sig_bodyhash(pdkim_ctx * ctx, pdkim_signature * sig)
+{
+pdkim_bodyhash * b = pdkim_set_bodyhash(ctx,
+			sig->hashtype, sig->canon_body, sig->bodylength);
+sig->calc_body_hash = b;
+return b;
+}
+
+
+/* -------------------------------------------------------------------------- */
+
+
 void
 pdkim_init_context(pdkim_ctx * ctx, BOOL dot_stuffed,
-  int(*dns_txt_callback)(char *, char *))
+  uschar * (*dns_txt_callback)(const uschar *))
 {
 memset(ctx, 0, sizeof(pdkim_ctx));
 ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN;
-ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN);
+/* The line buffer is for message data, hence tainted */
+ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, GET_TAINTED);
 DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback;
 }