X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/c5db348c5e29e93e51389fa0079f829967c5da82..01603eec64d42431f182b33008206facfc7f800e:/src/src/pdkim/pdkim.c

diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c
index 1420b1a79..9ebcfc1b6 100644
--- a/src/src/pdkim/pdkim.c
+++ b/src/src/pdkim/pdkim.c
@@ -2,7 +2,7 @@
  *  PDKIM - a RFC4871 (DKIM) implementation
  *
  *  Copyright (C) 2009 - 2016  Tom Kistner <tom@duncanthrax.net>
- *  Copyright (C) 2016 - 2017  Jeremy Harris <jgh@exim.org>
+ *  Copyright (C) 2016 - 2018  Jeremy Harris <jgh@exim.org>
  *
  *  http://duncanthrax.net/pdkim/
  *
@@ -26,8 +26,8 @@
 
 #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 +71,29 @@ 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[] = {
@@ -116,6 +121,32 @@ return string_sprintf("%s-%s",
 }
 
 
+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)
@@ -155,10 +186,11 @@ 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 +200,10 @@ 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 +225,10 @@ 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");
 }
@@ -224,13 +254,13 @@ 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 */
 
@@ -250,16 +280,19 @@ pdkim_free_ctx(pdkim_ctx *ctx)
 /* -------------------------------------------------------------------------- */
 /* Matches the name of the passed raw "header" against
    the passed colon-separated "tick", and invalidates
-   the entry in tick. Returns OK or fail-code */
-/*XXX might be safer done using a pdkim_stringlist for "tick" */
+   the entry in tick.  Entries can be prefixed for multi- or over-signing,
+   in which case do not invalidate.
+
+   Returns OK for a match, or fail-code
+*/
 
 static int
 header_name_match(const uschar * header, uschar * tick)
 {
-uschar * hname;
-uschar * lcopy;
-uschar * p;
-uschar * q;
+const uschar * ticklist = tick;
+int sep = ':';
+BOOL multisign;
+uschar * hname, * p, * ele;
 uschar * hcolon = Ustrchr(header, ':');		/* Get header name */
 
 if (!hcolon)
@@ -268,43 +301,37 @@ if (!hcolon)
 /* if we had strncmpic() we wouldn't need this copy */
 hname = string_copyn(header, hcolon-header);
 
-/* Copy tick-off list locally, so we can punch zeroes into it */
-p = lcopy = string_copy(tick);
-
-for (q = Ustrchr(p, ':'); q; q = Ustrchr(p, ':'))
+while (p = US ticklist, ele = string_nextinlist(&ticklist, &sep, NULL, 0))
   {
-  *q = '\0';
-  if (strcmpic(p, hname) == 0)
-    goto found;
-
-  p = q+1;
+  switch (*ele)
+  {
+  case '=': case '+':	multisign = TRUE; ele++; break;
+  default:		multisign = FALSE; break;
   }
 
-if (strcmpic(p, hname) == 0)
-  goto found;
-
+  if (strcmpic(ele, hname) == 0)
+    {
+    if (!multisign)
+      *p = '_';	/* Invalidate this header name instance in tick-off list */
+    return PDKIM_OK;
+    }
+  }
 return PDKIM_FAIL;
-
-found:
-  /* Invalidate header name instance in tick-off list */
-  tick[p-lcopy] = '_';
-  return PDKIM_OK;
 }
 
 
 /* -------------------------------------------------------------------------- */
 /* 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);
 uschar * q = relaxed;
 
-for (p = header; *p; p++)
+for (const uschar * p = header; p - header < len; p++)
   {
   uschar c = *p;
 
@@ -340,6 +367,13 @@ 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
 
@@ -400,19 +434,18 @@ 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);
 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);
 }
 
 
@@ -425,13 +458,12 @@ 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));
 memset(sig, 0, sizeof(pdkim_signature));
@@ -444,7 +476,7 @@ sig->hashtype = -1;
 
 q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1);
 
-for (p = raw_hdr; ; p++)
+for (uschar * p = raw_hdr; ; p++)
   {
   char c = *p;
 
@@ -492,7 +524,12 @@ 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);
@@ -501,62 +538,68 @@ 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)))
+	      for (int i = 0; i < nelem(pdkim_keytypes); i++)
+		if (Ustrcmp(elem, pdkim_keytypes[i]) == 0)
+		  { sig->keytype = i; break; }
+	    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;
@@ -578,6 +621,9 @@ 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'))
@@ -594,22 +640,17 @@ DEBUG(D_acl)
 	  "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\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 = ';';
@@ -631,7 +672,7 @@ 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;
@@ -645,7 +686,8 @@ 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");
@@ -653,9 +695,7 @@ 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 */
@@ -669,29 +709,21 @@ 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, blob * orig_data, blob * relaxed_data)
 {
 blob * canon_data = orig_data;
 /* 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
@@ -702,7 +734,7 @@ 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')
@@ -728,15 +760,15 @@ 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
+if (  b->bodylength >= 0
+   && b->signed_body_bytes + (unsigned long)canon_data->len > b->bodylength
    )
-  canon_data->len = sig->bodylength - sig->signed_body_bytes;
+  canon_data->len = b->bodylength - b->signed_body_bytes;
 
 if (canon_data->len > 0)
   {
-  exim_sha_update(&sig->body_hash_ctx, CUS canon_data->data, canon_data->len);
-  sig->signed_body_bytes += canon_data->len;
+  exim_sha_update(&b->body_hash_ctx, CUS canon_data->data, canon_data->len);
+  b->signed_body_bytes += canon_data->len;
   DEBUG(D_acl) pdkim_quoteprint(canon_data->data, canon_data->len);
   }
 
@@ -749,32 +781,33 @@ 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("PDKIM: finish bodyhash %d/%d/%ld len %ld\n",
+	    b->hashtype, 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"
+    debug_printf("PDKIM [%s] Body bytes (%s) 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);
+	sig->domain, pdkim_canons[b->canon_method], b->signed_body_bytes,
+	sig->domain, 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;
     }
 
@@ -782,9 +815,10 @@ 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
+       && 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("PDKIM [%s] Body hash compared OK\n", sig->domain);
       }
     else
       {
@@ -805,20 +839,18 @@ 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;
@@ -828,12 +860,12 @@ 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;
 
@@ -857,14 +889,15 @@ 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;
@@ -873,25 +906,25 @@ 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);
@@ -911,19 +944,21 @@ 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;
 (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);
@@ -943,6 +978,7 @@ 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. */
@@ -959,6 +995,13 @@ else
       while (last_sig->next) last_sig = last_sig->next;
       last_sig->next = sig;
       }
+
+    if (--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 */
@@ -978,15 +1021,14 @@ 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)
     {
@@ -1179,6 +1221,8 @@ return str;
 
 /* -------------------------------------------------------------------------- */
 
+/* Signing: create signature header
+*/
 static uschar *
 pdkim_create_header(pdkim_signature * sig, BOOL final)
 {
@@ -1229,7 +1273,7 @@ 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 */
@@ -1285,6 +1329,28 @@ 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("PDKIM: unexpected pubkey len %lu\n", 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)
@@ -1296,10 +1362,7 @@ 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'
    )
   {
@@ -1318,7 +1381,7 @@ DEBUG(D_acl)
   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)
    )
   {
@@ -1341,7 +1404,30 @@ DEBUG(D_acl) debug_printf(
       "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\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)
+  {
+  for(int i = 0; i < nelem(pdkim_keytypes); i++)
+    if (Ustrcmp(p->keytype, pdkim_keytypes[i]) == 0)
+      { sig->keytype = i; goto k_ok; }
+  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;
+  }
+k_ok:
+
+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)))
   {
   DEBUG(D_acl) debug_printf("verify_init: %s\n", *errstr);
   sig->verify_status =      PDKIM_VERIFY_INVALID;
@@ -1349,6 +1435,7 @@ if ((*errstr = exim_dkim_verify_init(&p->key, vctx)))
   return NULL;
   }
 
+vctx->keytype = sig->keytype;
 return p;
 }
 
@@ -1359,7 +1446,7 @@ 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
@@ -1372,28 +1459,67 @@ 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");
 
-/* Build (and/or evaluate) body hash */
+/* Build (and/or evaluate) body hash.  Do this even if no DKIM sigs, in case we
+have a hash to do for ARC. */
+
 pdkim_finish_bodyhash(ctx);
 
-for (sig = ctx->sig; sig; sig = sig->next)
+if (!ctx->sig)
+  {
+  DEBUG(D_acl) debug_printf("PDKIM: 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("PDKIM: [%s] abandoning this signature\n", sig->domain);
+    continue;
+    }
+
+  /*XXX The hash of the headers is needed for GCrypt (for which we can do RSA
+  suging 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,
+      "PDKIM: hash setup error, possibly nonhandled hashtype");
     break;
     }
 
@@ -1404,7 +1530,8 @@ for (sig = ctx->sig; sig; sig = sig->next)
 	sig->sign_headers);
 
   DEBUG(D_acl) debug_printf(
-      "PDKIM >> Header data for hash, canonicalized, in sequence >>>>>>>>>>>>\n");
+      "PDKIM >> Header data for hash, canonicalized (%-7s), in sequence >>\n",
+	pdkim_canons[sig->canon_headers]);
 
 
   /* SIGNING ---------------------------------------------------------------- */
@@ -1416,14 +1543,23 @@ 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  */
 
-    for (p = sig->headers; p; p = p->next)
+/*XXX extend for non-RSA algos */
+    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;
+
+    sig->headernames = NULL;			/* Collected signed header names */
+    for (pdkim_stringlist * p = sig->headers; p; p = p->next)
       {
       uschar * rh = p->value;
 
@@ -1439,17 +1575,24 @@ for (sig = ctx->sig; sig; sig = sig->next)
 	exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(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));
 	}
       }
 
-    /* Any headers we wanted to sign but were not present must also be listed */
+    /* Any headers we wanted to sign but were not present must also be listed.
+    Ignore elements that have been ticked-off or are marked as never-oversign. */
+
     l = sig->sign_headers;
     while((s = string_nextinlist(&l, &sep, NULL, 0)))
-      if (*s != '_')
+      {
+      if (*s == '+')			/* skip oversigning marker */
+        s++;
+      if (*s != '_' && *s != '=')
 	g = string_append_listele(g, ':', s);
+      }
     sig->headernames = string_from_gstring(g);
 
     /* Create signature header with b= omitted */
@@ -1463,12 +1606,11 @@ 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);
@@ -1478,7 +1620,7 @@ 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)] == ':'
@@ -1524,8 +1666,8 @@ for (sig = ctx->sig; sig; sig = sig->next)
 
   DEBUG(D_acl)
     {
-    debug_printf(
-	    "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
+    debug_printf("PDKIM >> Signed DKIM-Signature header, canonicalized (%-7s) >>>>>>>\n",
+	    pdkim_canons[sig->canon_headers]);
     pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr));
     debug_printf(
 	    "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
@@ -1550,31 +1692,28 @@ 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;
       }
 
@@ -1591,6 +1730,7 @@ 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
@@ -1607,11 +1747,19 @@ 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"
+	  "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\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;
       }
-
+ 
     /* Make sure sig uses supported DKIM version (only v1) */
     if (sig->version != 1)
       {
@@ -1631,7 +1779,12 @@ for (sig = ctx->sig; sig; sig = sig->next)
       }
 
     if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx, err)))
+      {
+      log_write(0, LOG_MAIN, "PDKIM: %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 */
@@ -1654,11 +1807,17 @@ 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;
@@ -1669,14 +1828,18 @@ for (sig = ctx->sig; sig; sig = sig->next)
 
     /* 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;
+      }
 
 NEXT_VERIFY:
 
     DEBUG(D_acl)
       {
-      debug_printf("PDKIM [%s] signature status: %s",
-	      sig->domain, pdkim_verify_status_str(sig->verify_status));
+      debug_printf("PDKIM [%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));
@@ -1690,14 +1853,15 @@ 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)(uschar *), BOOL dot_stuffing)
 {
 pdkim_ctx * ctx;
 
@@ -1714,8 +1878,6 @@ 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,
@@ -1737,22 +1899,15 @@ 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,
+    "PDKIM: unrecognised hashname '%s'", hashname);
   return NULL;
   }
 
@@ -1799,9 +1954,70 @@ 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;
+
+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("PDKIM: using existing bodyhash %d/%d/%ld\n",
+				  hashtype, canon_method, bodylength);
+    return b;
+    }
+
+DEBUG(D_receive) debug_printf("PDKIM: new bodyhash %d/%d/%ld\n",
+			      hashtype, canon_method, bodylength);
+b = store_get(sizeof(pdkim_bodyhash));
+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("PDKIM: 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)(uschar *))
 {
 memset(ctx, 0, sizeof(pdkim_ctx));
 ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN;