X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git;a=blobdiff_plain;f=src%2Freply.c;h=71586688bcba7ac4a238fab575d235c68dcdad0d;hp=b6218c1673e94ee7f48a715d5a10126bed44a065;hb=0ba0614a998909d8b4f51988d7a8af3ba369a5d9;hpb=b9de380c1e587b6c5828cb9de796746024946880;ds=sidebyside diff --git a/src/reply.c b/src/reply.c index b6218c1..7158668 100644 --- a/src/reply.c +++ b/src/reply.c @@ -38,13 +38,50 @@ static void vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len) { } } +static adns_status get_label(const byte *dgram, int dglen, int *max_io, + int *cbyte_io, int *lablen_r, int *labstart_r, + int *namelen_io) { + /* If succeeds, *lablen_r may be set to -1 to indicate truncation/overrun */ + int max, cbyte, lablen, namelen; + + max= *max_io; + cbyte= *cbyte_io; + + for (;;) { + if (cbyte+2 > max) goto x_truncated; + GET_W(cbyte,lablen); + if (!(lablen & 0x0c000)) break; + if ((lablen & 0x0c000) != 0x0c000) return adns_s_unknownreply; + if (cbyte_io) { *cbyte_io= cbyte; cbyte_io= 0; } + cbyte= dgram+DNS_HDR_SIZE+(lablen&0x3fff); + *max_io= max= dglen; + } + if (labstart_r) *labstart_r= cbyte; + if (lablen) { + namelen= *namelen_io; + if (namelen) namelen++; + namelen+= lablen; + if (namelen > DNS_MAXDOMAIN) return adns_s_domaintoolong; + *namelen_io= namelen; + cbyte+= lablen; + if (cbyte > max) goto x_truncated; + } + if (cbyte_io) *cbyte_io= cbyte; + *lablen_r= lablen; + return adns_s_ok; + + x_truncated: + *lablen_r= -1; + return adns_s_ok; +} + static adns_status get_domain_perm(adns_state ads, adns_query qu, int serv, const byte *dgram, int dglen, int *cbyte_io, int max, char **domain_r) { /* Returns 0 for OK (*domain_r set) or truncated (*domain_r null) * or any other adns_s_* value. */ - int cbyte, sused, lablen; + int cbyte, sused, lablen, namelen; /* If we follow a pointer we set cbyte_io to 0 to indicate that * we've lost our original starting and ending points; we don't @@ -53,31 +90,25 @@ static adns_status get_domain_perm(adns_state ads, adns_query qu, int serv, cbyte= *cbyte_io; sused= qu->ans.used; *domain_r= 0; + namelen= 0; for (;;) { - if (cbyte>=max) goto x_truncated; - lablen= GET_B(cbyte); + st= get_label(dgram,dglen,&max, &cbyte,&lablen,&labstart,&namelen); + if (st) return st; + if (lablen<0) goto x_truncated; if (!lablen) break; - if (lablen&0x0c000) { - if ((lablen&0x0c000) != 0x0c0000) return adns_s_unknownreply; - if (cbyte_io) { *cbyte_io= cbyte; cbyte_io= 0; } - cbyte= (lablen&0x3fff) + DNS_HDR_SIZE; - max= dglen; - continue; - } - if (cbyte+lablen>=max) bgoto x_truncated; if (qu->ans.used != sused) if (!adns__vbuf_append(&qu->ans,".",1)) return adns_s_nolocalmem; if (qu->flags & adns_qf_anyquote) { - if (!vbuf__append_quoted1035(&qu->ans,dgram+cbyte,lablen)) + if (!vbuf__append_quoted1035(&qu->ans,dgram+labstart,lablen)) return adns_s_nolocalmem; } else { - if (!ctype_isalpha(dgram[cbyte])) return adns_s_invaliddomain; + if (!ctype_isalpha(dgram[labstart])) return adns_s_invaliddomain; for (i= cbyte+1; ians,dgram+cbyte,lablen)) + if (!adns__vbuf_append(&qu->ans,dgram+labstart,lablen)) return adns_s_nolocalmem; } } @@ -102,22 +133,48 @@ static adns_status get_domain_temp(adns_state ads, adns_query qu, int serv, return st; } -/* fixme: sensible comparison of owners */ - static adns_status get_rr_temp(adns_state ads, adns_query qu, int serv, - const byte *dgram, int dglen, - int *cbyte_io, + const byte *dgram, int dglen, int *cbyte_io, int *type_r, int *class_r, int *rdlen_r, int *rdstart_r, - char **owner_r) { - int cbyte, tmp, rdlen; + const byte *eo_dgram, int eo_dglen, int eo_cbyte, + int *eo_matched_r) { + /* _s_ok can have *type_r == -1 and other output invalid, for truncation + * type_r and class_r must be !0, other _r may be 0. + * eo_dgram==0 for no comparison, otherwise all eo_ must be valid. + */ + int cbyte, tmp, rdlen, mismatch; + int max, lablen, labstart, namelen; + int eo_max, eo_lablen, eo_labstart, eo_namelen; cbyte= *cbyte_io; - st= get_domain_temp(ads,qu,serv,dgram,dglen,&cbyte,dglen,owner_r); - if (st) return st; + mismatch= eo_dgram ? 1 : 0; + + namelen= 0; eo_namelen= 0; + max= dglen; eo_max= eo_dglen; + for (;;) { + st= get_label(dgram,dglen,&max, + &cbyte,&lablen,&labstart,&namelen); + if (st) return st; + if (lablen<0) goto x_truncated; + + if (!mismatch) { + st= get_label(eo_dgram,eo_dglen,&eo_max, + &eo_cbyte,&eo_lablen,&eo_labstart,&eo_namelen); + if (st) return st; + assert(eo_lablen>=0); + if (lablen != eo_lablen) mismatch= 1; + while (!mismatch && lablen-- > 0) { + ch= dgram[labstart++]; if (ctype_isalpha(ch)) ch &= ~32; + eo_ch= eo_dgram[eo_labstart++]; if (ctype_isalpha(eo_ch)) eo_ch &= ~32; + if (ch != eo_ch) mismatch= 1 + } + } + } + if (eo_matched_r) *eo_matched_r= !mismatch; if (cbyte+10>len) goto x_truncated; - GET_W(cbyte,tmp); if (type_r) *type_r= tmp; - GET_W(cbyte,tmp); if (class_r) *class_r= tmp; + GET_W(cbyte,tmp); *type_r= tmp; + GET_W(cbyte,tmp); *class_r= tmp; cbyte+= 4; /* we skip the TTL */ GET_W(cbyte,rdlen); if (rdlen_r) *rdlen_r= tmp; if (rdstart_r) *rdstart_r= cbyte; @@ -127,11 +184,12 @@ static adns_status get_rr_temp(adns_state ads, adns_query qu, int serv, return adns_s_ok; x_truncated: - *owner_r= 0; return 0;; + *type_r= -1; + return 0;; } void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { - int cbyte, anstart, rrstart, lablen, wantedrrs, get_t; + int cbyte, anstart, rrstart, lablen, wantedrrs, get_t, cnamestart; cbyte= 0; @@ -148,6 +206,8 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { GET_W(cbyte,arcount); assert(cbyte == DNS_HDR_SIZE); + flg_ra= f2&0x80; + if (f1&0x80) { adns__diag(ads,serv,"server sent us a query, not a response"); return; @@ -216,27 +276,43 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { wantedrrs= 0; for (rri= 0; rricname) { + st= get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte, + &rrtype,&rrclass,&rdlength,&rdstart, + dgram,dglen,cnamestart, &ownermatched); + } else { + st= get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte, + &rrtype,&rrclass,&rdlength,&rdstart, + qu->querymsg,qu->querylen,DNS_HDR_SIZE, &ownermatched); + } if (st) adns__query_fail(ads,qu,st); + if (rrtype == -1) goto x_truncated; + if (rrclass != DNS_CLASS_IN) { - adns__diag(ads,serv,"ignoring RR with wrong class %d (expected IN=%d)", + adns__diag(ads,serv,"ignoring answer RR with wrong class %d (expected IN=%d)", rrclass,DNS_CLASS_IN); continue; } - if (strcmp_quoted1035(cowner, qu->cname ? qu->cname : qu->owner)) { - adns__debug(ads,serv,"ignoring answer RR with irrelevant owner \"%s\"",cowner); + if (!ownermatched) { + if (ads->iflag & adns_if_debug) { + st= get_domain_temp(ads,qu,serv, dgram,dglen,&rrstart,dglen, &cowner); + if (st) adns__debug(ads,serv,"ignoring RR with an irrelevant owner, code %d",st); + else adns__debug(ads,serv,"ignoring RR with an irrelevant owner \"%s\"",cowner); + } continue; } if (!qu->cname && (qu->type & adns__rrt_typemask) != adns_cname && rrtype == adns_cname) { /* Ignore second and subsequent CNAMEs */ - qu->cname= get_domain_perm(ads,qu,dgram,len,rdstart,rdstart+rdlength); - /* If we find the answer section truncated after this point we restart - * the query at the CNAME; otherwise we can use it as-is. - */ + st= get_domain_perm(ads,qu,serv, dgram,dglen, + &rdstart,rdstart+rdlength,&qu->cname); + if (st) return st; + if (!qu->cname) goto x_truncated; + /* If we find the answer section truncated after this point we restart + * the query at the CNAME; if beforehand then we obviously have to use + * TCP. If there is no truncation we can use the whole answer if + * it contains the relevant info. + */ } else if (rrtype == (qu->type & adns__rrt_typemask)) { wantedrrs++; } else { @@ -251,23 +327,60 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */ if (rcode == rcode_nxdomain) { - adnns__query_finish(ads,qu,adns_s_nxdomain); + adns__query_finish(ads,qu,adns_s_nxdomain); return; } /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */ + foundsoa= 0; foundns= 0; for (rri= 0; rricname) { + cname_recurse(ads,qu); + return; + } + + /* Bloody hell, I thought we asked for recursion ? */ + if (!flg_ra) { + adns__diag(ads,serv,"server is not willing to do recursive lookups for us"); + adns__query_fail(ads,qu,adns_s_norecurse); + return; + } + adns__diag(ads,serv,"server claims to do recursion, but gave us a referral"); + adns__query_fail(ads,qu,adns_s_serverfault); return; } + /* Now, we have some RRs which we wanted. */ + rrs= + + } + } else { + +{ truncated(ads,qu,flg_ra); return; } ) { if (type @@ -296,3 +409,42 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { adns__diag(ads,serv,"received datagram size %d",len); } + + while ( + switch (type) { + case adns_r_a: + adns_r_a_mf= adns_r_a|adns__qtf_masterfmt, + + adns_r_ns_raw= 2, + adns_r_ns= adns_r_ns_raw|adns__qtf_deref, + adns_r_ns_mf= adns_r_ns_raw|adns__qtf_masterfmt, + + adns_r_cname= 5, + adns_r_cname_mf= adns_r_cname|adns__qtf_masterfmt, + + adns_r_soa_raw= 6, + adns_r_soa= adns_r_soa_raw|adns__qtf_mail822, + adns_r_soa_mf= adns_r_soa_raw|adns__qtf_masterfmt, + + adns_r_null= 10, + adns_r_null_mf= adns_r_null|adns__qtf_masterfmt, + + adns_r_ptr_raw= 12, + adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref, + adns_r_ptr_mf= adns_r_ptr_raw|adns__qtf_masterfmt, + + adns_r_hinfo= 13, + adns_r_hinfo_mf= adns_r_hinfo|adns__qtf_masterfmt, + + adns_r_mx_raw= 15, + adns_r_mx= adns_r_mx_raw|adns__qtf_deref, + adns_r_mx_mf= adns_r_mx_raw|adns__qtf_masterfmt, + + adns_r_txt= 16, + adns_r_txt_mf= adns_r_txt|adns__qtf_masterfmt, + + adns_r_rp_raw= 17, + adns_r_rp= adns_r_rp_raw|adns__qtf_mail822, + adns_r_rp_mf= adns_r_rp_raw|adns__qtf_masterfmt + +