* Exim - an Internet mail transport agent *
*************************************************/
/* Experimental ARC support for Exim
- Copyright (c) Jeremy Harris 2018
+ Copyright (c) Jeremy Harris 2018 - 2020
License: GPL
*/
static uschar *
arc_insert_hdr(arc_ctx * ctx, header_line * h, unsigned off, unsigned hoff,
- BOOL instance_only)
+ BOOL instance_only, arc_line ** alp_ret)
{
unsigned i;
arc_set * as;
if (*(alp = (arc_line **)(US as + hoff))) return US"dup hdr";
*alp = al;
+if (alp_ret) *alp_ret = al;
return NULL;
}
debug_printf("ARC: found AAR: %.*s\n", len, h->text);
}
if ((e = arc_insert_hdr(ctx, h, ARC_HDRLEN_AAR, offsetof(arc_set, hdr_aar),
- TRUE)))
+ TRUE, NULL)))
{
DEBUG(D_acl) debug_printf("inserting AAR: %s\n", e);
return US"inserting AAR";
debug_printf("ARC: found AMS: %.*s\n", len, h->text);
}
if ((e = arc_insert_hdr(ctx, h, ARC_HDRLEN_AMS, offsetof(arc_set, hdr_ams),
- instance_only)))
+ instance_only, &ams)))
{
DEBUG(D_acl) debug_printf("inserting AMS: %s\n", e);
return US"inserting AMS";
}
/* defaults */
- /*XXX dubious selection of ams here */
- ams = ctx->arcset_chain->hdr_ams;
if (!ams->c.data)
{
ams->c_head.data = US"simple"; ams->c_head.len = 6;
debug_printf("ARC: found AS: %.*s\n", len, h->text);
}
if ((e = arc_insert_hdr(ctx, h, ARC_HDRLEN_AS, offsetof(arc_set, hdr_as),
- instance_only)))
+ instance_only, NULL)))
{
DEBUG(D_acl) debug_printf("inserting AS: %s\n", e);
return US"inserting AS";
/* Setup the interface to the signing library */
-if ((errstr = exim_dkim_verify_init(&p->key, KEYFMT_DER, &vctx)))
+if ((errstr = exim_dkim_verify_init(&p->key, KEYFMT_DER, &vctx, NULL)))
{
DEBUG(D_acl) debug_printf("ARC verify init: %s\n", errstr);
as->ams_verify_done = arc_state_reason = US"internal sigverify init error";
/* We know the b-tag blob is of a nul-term string, so safe as a string */
pdkim_decode_base64(hdr_as->b.data, &sighash);
-if ((errstr = exim_dkim_verify_init(&p->key, KEYFMT_DER, &vctx)))
+if ((errstr = exim_dkim_verify_init(&p->key, KEYFMT_DER, &vctx, NULL)))
{
DEBUG(D_acl) debug_printf("ARC verify init: %s\n", errstr);
return US"fail";
arc_sign_append_aar(gstring * g, arc_ctx * ctx,
const uschar * identity, int instance, blob * ar)
{
-int aar_off = g ? g->ptr : 0;
+int aar_off = gstring_length(g);
arc_set * as =
store_get(sizeof(arc_set) + sizeof(arc_line) + sizeof(header_line), FALSE);
arc_line * al = (arc_line *)(as+1);
const uschar * privkey, unsigned options)
{
gstring * arcset;
-arc_set * as;
uschar * status = arc_ar_cv_status(ar);
arc_line * al = store_get(sizeof(header_line) + sizeof(arc_line), FALSE);
header_line * h = (header_line *)(al+1);
+uschar * badline_str;
gstring * hdata = NULL;
int hashtype = pdkim_hashname_to_hashtype(US"sha256", 6); /*XXX hardwired */
- all ARC set headers, set-number order, aar then ams then as,
including self (but with an empty b= in self)
*/
+DEBUG(D_transport) debug_printf("ARC: building AS for status '%s'\n", status);
/* Construct the AS except for the signature */
/* For any but "fail" chain-verify status, walk the entire chain in order by
instance. For fail, only the new arc-set. Accumulate the elements walked. */
-for (as = Ustrcmp(status, US"fail") == 0
+for (arc_set * as = Ustrcmp(status, US"fail") == 0
? ctx->arcset_chain_last : ctx->arcset_chain;
as; as = as->next)
{
+ arc_line * l;
/* Accumulate AAR then AMS then AS. Relaxed canonicalisation
is required per standard. */
- h = as->hdr_aar->complete;
+ badline_str = US"aar";
+ if (!(l = as->hdr_aar)) goto badline;
+ h = l->complete;
hdata = string_cat(hdata, pdkim_relax_header_n(h->text, h->slen, TRUE));
- h = as->hdr_ams->complete;
+ badline_str = US"ams";
+ if (!(l = as->hdr_ams)) goto badline;
+ h = l->complete;
hdata = string_cat(hdata, pdkim_relax_header_n(h->text, h->slen, TRUE));
- h = as->hdr_as->complete;
+ badline_str = US"as";
+ if (!(l = as->hdr_as)) goto badline;
+ h = l->complete;
hdata = string_cat(hdata, pdkim_relax_header_n(h->text, h->slen, !!as->next));
}
/* Finally, append the AMS and AAR to the new AS */
return string_catn(arcset, arcset_interim->s, arcset_interim->ptr);
+
+badline:
+ DEBUG(D_transport)
+ debug_printf("ARC: while building AS, missing %s in chain\n", badline_str);
+ return NULL;
}
+/* Per RFCs 6376, 7489 the only allowed chars in either an ADMD id
+or a selector are ALPHA/DIGGIT/'-'/'.'
+
+Check, to help catch misconfigurations such as a missing selector
+element in the arc_sign list.
+*/
+
+static BOOL
+arc_valid_id(const uschar * s)
+{
+for (uschar c; c = *s++; )
+ if (!isalnum(c) && c != '-' && c != '.') return FALSE;
+return TRUE;
+}
+
+
+
/* ARC signing. Called from the smtp transport, if the arc_sign option is set.
The dkim_exim_sign() function has already been called, so will have hashed the
message body for us so long as we requested a hash previously.
if ( !*identity || !*selector
|| !(privkey = string_nextinlist(&signspec, &sep, NULL, 0)) || !*privkey)
{
- log_write(0, LOG_MAIN, "ARC: bad signing-specification (%s)",
- !*identity ? "identity" : !*selector ? "selector" : "private-key");
- return sigheaders ? sigheaders : string_get(0);
+ s = !*identity ? US"identity" : !*selector ? US"selector" : US"private-key";
+ goto bad_arg_ret;
}
+if (!arc_valid_id(identity))
+ { s = US"identity"; goto bad_arg_ret; }
+if (!arc_valid_id(selector))
+ { s = US"selector"; goto bad_arg_ret; }
if (*privkey == '/' && !(privkey = expand_file_big_buffer(privkey)))
return sigheaders ? sigheaders : string_get(0);
(void) string_from_gstring(g);
gstring_release_unused(g);
return g;
+
+
+bad_arg_ret:
+ log_write(0, LOG_MAIN, "ARC: bad signing-specification (%s)", s);
+ return sigheaders ? sigheaders : string_get(0);
}
git://git.exim.org / exim.git / blobdiff