X-Git-Url: https://git.distorted.org.uk/~mdw/adns/blobdiff_plain/98a3f706175de88b2c9f0729b405330457ae680b..31144a72ed24e2d3cd62f5f1239e219737beeff4:/src/parse.c diff --git a/src/parse.c b/src/parse.c index 2a9dd94..957b572 100644 --- a/src/parse.c +++ b/src/parse.c @@ -26,73 +26,89 @@ int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len) { return 1; } -adns_status adns__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; +void adns__findlabel_start(findlabel_state *fls, + adns_state ads, int serv, + const byte *dgram, int dglen, int max, + int dmbegin, int *dmend_rlater) { + fls->ads= ads; + fls->serv= serv; + fls->dgram= dgram; + fls->dglen= dglen; + fls->max= max; + fls->cbyte= dmbegin; + fls->namelen= 0; + fls->dmend_r= dmend_rlater; + fls->namelen_r= namelen_rlater; +} - max= *max_io; - cbyte= *cbyte_io; - +adns_status adns__findlabel_next(findlabel_state fls, + int *lablen_r, int *labstart_r) { + int lablen, jumped; + + jumped= 0; for (;;) { - if (cbyte+2 > max) goto x_truncated; - GET_W(cbyte,lablen); + fls->cbyte += 2; + if (fls->cbyte > fls->dglen) goto x_truncated; + if (fls->cbyte > fls->max) goto x_serverfaulty; + GET_W(fls->cbyte-2,lablen); if (!(lablen & 0x0c000)) break; if ((lablen & 0x0c000) != 0x0c000) return adns_s_unknownreply; - if (cbyte_io) { *cbyte_io= cbyte; cbyte_io= 0; } - cbyte= DNS_HDRSIZE+(lablen&0x3fff); - *max_io= max= dglen; + if (jumped++) { + adns__diag(ads,serv,"compressed datagram contains loop"); + return adns_s_serverfaulty; + } + if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte; + fls->cbyte= DNS_HDRSIZE+(lablen&0x3fff); + fls->dmend_r= 0; fls->max= fls->dglen+1; } - 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 (fls->namelen) fls->namelen++; + fls->namelen+= lablen; + if (fls->namelen > DNS_MAXDOMAIN) return adns_s_domaintoolong; + fls->cbyte+= lablen; + if (fls->cbyte > fls->dglen) goto x_truncated; + if (fls->cbyte > fls->max) goto x_serverfaulty; + } else { + if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte; + if (fls->namelen_r) *(fls->namelen_r)= fls->namelen; } - if (cbyte_io) *cbyte_io= cbyte; + if (labstart_r) *labstart_r= fls->cbyte; *lablen_r= lablen; return adns_s_ok; x_truncated: *lablen_r= -1; return adns_s_ok; + + x_serverfaulty: + adns__diag(ads,serv,"label in domain runs beyond end of domain"); + return adns_s_serverfaulty; } -adns_status adns__get_domain_perm(adns_state ads, adns_query qu, int serv, - const byte *dgram, int dglen, - int *cbyte_io, int max, int *domainstart_r) { - /* Returns 0 for OK (*domainstart_r >=0) or truncated (*domainstart_r == -1) - * or any other adns_s_* value. - */ - int cbyte, sused, lablen, labstart, namelen, i, ch; +adns_status adns__parse_domain(adns_state ads, int serv, vbuf *vb, int flags, + const byte *dgram, int dglen, + int *cbyte_io, int max) { + findlabel_state fls; + + int cbyte, lablen, labstart, namelen, i, ch; adns_status st; - /* 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 - * put the end of the pointed-to thing into the original *cbyte_io. - */ - cbyte= *cbyte_io; - sused= qu->ans.used; - namelen= 0; + ands__findlabel_start(&fls,ads,serv, dgram,dglen,max, *cbyte_io,cbyte_io); + vb->used= 0; for (;;) { - st= adns__get_label(dgram,dglen,&max, &cbyte,&lablen,&labstart,&namelen); + st= adns__findlabel_next(&fls,&lablen,&labstart); if (st) return st; - if (lablen<0) goto x_truncated; + if (lablen<0) { vb->used=0; return adns_s_ok; } if (!lablen) break; - if (qu->ans.used != sused) + if (vb->used) if (!adns__vbuf_append(&qu->ans,".",1)) return adns_s_nolocalmem; - if (qu->flags & adns_qf_anyquote) { + if (flags & adns_qf_anyquote) { if (!vbuf__append_quoted1035(&qu->ans,dgram+labstart,lablen)) return adns_s_nolocalmem; } else { if (!ctype_alpha(dgram[labstart])) return adns_s_invaliddomain; - for (i= cbyte+1; ians,"",1)) return adns_s_nolocalmem; - *domainstart_r= sused; return adns_s_ok; - - x_truncated: - *domainstart_r= -1; - return cbyte_io ? -1 : adns_s_serverfaulty; } - -adns_status adns__get_domain_temp(adns_state ads, adns_query qu, int serv, - const byte *dgram, int dglen, - int *cbyte_io, int max, int *domainstart_r) { - int sused; + +const char *adns__diag_domain(adns_state ads, int serv, vbuf *vb, int flags, + const byte *dgram, int dglen, int cbyte) { adns_status st; - sused= qu->ans.used; - st= adns__get_domain_perm(ads,qu,serv,dgram,dglen,cbyte_io,max,domainstart_r); - qu->ans.used= sused; - return st; + st= adns__parse_domain(ads,serv,vb,qu->flags, dgram,dglen, &cbyte,dglen); + if (st) { + vb->used= 0; + adns__vbuf_appendstr(vb,""); + adns__vbuf_append(vb,"",1); + } + if (!vb.used) { + adns__vbuf_appendstr(vb,""); + adns__vbuf_append(vb,"",1); + } + return vb->buf; } - -adns_status adns__get_rr_temp(adns_state ads, adns_query qu, int serv, - const byte *dgram, int dglen, int *cbyte_io, - int *type_r, int *class_r, int *rdlen_r, int *rdstart_r, - 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. + +adns_status adns__findrr(adns_state ads, int serv, + const byte *dgram, int dglen, int *cbyte_io, + int *type_r, int *class_r, int *rdlen_r, int *rdstart_r, + const byte *eo_dgram, int eo_dglen, int eo_cbyte, + int *eo_matched_r) { + /* Finds the extent and some of the contents of an RR in a datagram + * and does some checks. The datagram is *dgram, length dglen, and + * the RR starts at *cbyte_io (which is updated afterwards to point + * to the end of the RR). + * + * The type, class and RRdata length and start are returned iff + * the corresponding pointer variables are not null. type_r and + * class_r may not be null. + * + * If the caller thinks they know what the owner of the RR ought to + * be they can pass in details in eo_*: this is another (or perhaps + * the same datagram), and a pointer to where the putative owner + * starts in that datagram. In this case *eo_matched_r will be set + * to 1 if the datagram matched or 0 if it did not. Either + * both eo_dgram and eo_matched_r must both be non-null, or they + * must both be null (in which case eo_dglen and eo_cbyte will be ignored). + * The eo datagram and contained owner domain MUST be valid and + * untruncated. + * + * If there is truncation then *type_r will be set to -1 and + * *cbyte_io, *class_r, *rdlen_r, *rdstart_r and *eo_matched_r will be + * undefined. + * + * If an error is returned then *type_r will be undefined too. */ - int cbyte, tmp, rdlen, mismatch; + findlabel_state fls, eo_fls; + int cbyte; + + int tmp, rdlen, mismatch; int max, lablen, labstart, namelen, ch; int eo_max, eo_lablen, eo_labstart, eo_namelen, eo_ch; adns_status st; cbyte= *cbyte_io; - mismatch= eo_dgram ? 1 : 0; - namelen= 0; eo_namelen= 0; - max= dglen; eo_max= eo_dglen; + ands__findlabel_start(&fls,ads,serv, dgram,dglen,dglen,cbyte,&cbyte); + if (eo_dgram) { + ands__findlabel_start(&eo_fls,ads,serv, eo_dgram,eo_dglen,eo_dglen,eo_cbyte,0); + mismatch= 0; + } else { + mismatch= 1; + } + for (;;) { - st= adns__get_label(dgram,dglen,&max, - &cbyte,&lablen,&labstart,&namelen); + st= adns__findlabel_next(&fls,&lablen,&labstart); if (st) return st; if (lablen<0) goto x_truncated; if (!mismatch) { - st= adns__get_label(eo_dgram,eo_dglen,&eo_max, - &eo_cbyte,&eo_lablen,&eo_labstart,&eo_namelen); - if (st) return st; - assert(eo_lablen>=0); + st= adns__findlabel_next(&eo_fls,&eo_lablen,&eo_labstart); + assert(!st); assert(eo_lablen>=0); if (lablen != eo_lablen) mismatch= 1; while (!mismatch && lablen-- > 0) { ch= dgram[labstart++]; if (ctype_alpha(ch)) ch &= ~32;