From: Wolfgang Breyha Date: Fri, 20 Dec 2019 14:01:23 +0000 (+0000) Subject: SPF: only require "v=spf1" on TXT DNS records during lookups. Bug 2499 X-Git-Url: https://git.exim.org/users/jgh/exim.git/commitdiff_plain/4a3709fb2cfb1ec26ac60bcdb8bbc078d3377ddc SPF: only require "v=spf1" on TXT DNS records during lookups. Bug 2499 --- diff --git a/src/src/spf.c b/src/src/spf.c index 1955b5d96..b7041d3e3 100644 --- a/src/src/spf.c +++ b/src/src/spf.c @@ -43,17 +43,15 @@ dns_answer * dnsa = store_get_dns_answer(); dns_scan dnss; SPF_dns_rr_t * spfrr; -DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup\n"); +DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup '%s'\n", domain); if (dns_lookup(dnsa, US domain, rr_type, NULL) == DNS_SUCCEED) for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if ( rr->type == rr_type - && Ustrncmp(rr->data+1, "v=spf1", 6) == 0) + && (rr_type != T_TXT || Ustrncmp(rr->data+1, "v=spf1", 6) == 0)) { - gstring * g = NULL; - uschar chunk_len; - uschar * s; + const uschar * s = rr->data; SPF_dns_rr_t srr = { .domain = CS rr->name, /* query information */ .domain_buf_len = DNS_MAXNAME, @@ -71,19 +69,49 @@ if (dns_lookup(dnsa, US domain, rr_type, NULL) == DNS_SUCCEED) .source = spf_dns_server }; - for (int off = 0; off < rr->size; off += chunk_len) + switch(rr_type) { - chunk_len = (rr->data)[off++]; - g = string_catn(g, US ((rr->data)+off), chunk_len); + case T_MX: + s += 2; /* skip the MX precedence field */ + case T_PTR: + { + uschar * buf = store_malloc(256); + (void)dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen, s, + (DN_EXPAND_ARG4_TYPE)buf, 256); + s = buf; + break; + } + + case T_TXT: + { + gstring * g = NULL; + uschar chunk_len; + for (int off = 0; off < rr->size; off += chunk_len) + { + if (!(chunk_len = s[off++])) break; + g = string_catn(g, s+off, chunk_len); + } + if (!g) + { + HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an " + "empty name: treated as non-existent host name\n"); + continue; + } + gstring_release_unused(g); + s = string_copy_malloc(string_from_gstring(g)); + break; + } + + case T_A: + case T_AAAA: + default: + { + uschar * buf = store_malloc(dnsa->answerlen + 1); + s = memcpy(buf, s, dnsa->answerlen + 1); + break; + } } - if (!g) - { - HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an " - "empty name: treated as non-existent host name\n"); - continue; - } - gstring_release_unused(g); - s = string_copy_malloc(string_from_gstring(g)); + DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup '%s'\n", s); srr.rr = (void *) &s; /* spfrr->rr must have been malloc()d for this */