| 1 | /* |
| 2 | * parse.c |
| 3 | * - parsing assistance functions (mainly for domains inside datagrams) |
| 4 | */ |
| 5 | /* |
| 6 | * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License as published by |
| 10 | * the Free Software Foundation; either version 2, or (at your option) |
| 11 | * any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU General Public License |
| 19 | * along with this program; if not, write to the Free Software Foundation, |
| 20 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 21 | */ |
| 22 | |
| 23 | #include "internal.h" |
| 24 | |
| 25 | int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len) { |
| 26 | char qbuf[10]; |
| 27 | int i, ch; |
| 28 | |
| 29 | while (len) { |
| 30 | qbuf[0]= 0; |
| 31 | for (i=0; i<len; i++) { |
| 32 | ch= buf[i]; |
| 33 | if (ch == '.' || ch == '"' || ch == '(' || ch == ')' || |
| 34 | ch == '@' || ch == ';' || ch == '$' || ch == '\\') { |
| 35 | sprintf(qbuf,"\\%c",ch); |
| 36 | break; |
| 37 | } else if (ch <= ' ' || ch >= 127) { |
| 38 | sprintf(qbuf,"\\%03o",ch); |
| 39 | break; |
| 40 | } |
| 41 | } |
| 42 | if (!adns__vbuf_append(vb,buf,i) || !adns__vbuf_append(vb,qbuf,strlen(qbuf))) |
| 43 | return 0; |
| 44 | if (i<len) i++; |
| 45 | buf+= i; |
| 46 | len-= i; |
| 47 | } |
| 48 | return 1; |
| 49 | } |
| 50 | |
| 51 | void adns__findlabel_start(findlabel_state *fls, adns_state ads, |
| 52 | int serv, adns_query qu, |
| 53 | const byte *dgram, int dglen, int max, |
| 54 | int dmbegin, int *dmend_rlater) { |
| 55 | fls->ads= ads; |
| 56 | fls->qu= qu; |
| 57 | fls->serv= serv; |
| 58 | fls->dgram= dgram; |
| 59 | fls->dglen= dglen; |
| 60 | fls->max= max; |
| 61 | fls->cbyte= dmbegin; |
| 62 | fls->namelen= 0; |
| 63 | fls->dmend_r= dmend_rlater; |
| 64 | } |
| 65 | |
| 66 | adns_status adns__findlabel_next(findlabel_state *fls, |
| 67 | int *lablen_r, int *labstart_r) { |
| 68 | int lablen, jumped, jumpto; |
| 69 | const char *dgram; |
| 70 | |
| 71 | jumped= 0; |
| 72 | dgram= fls->dgram; |
| 73 | for (;;) { |
| 74 | if (fls->cbyte >= fls->dglen) goto x_truncated; |
| 75 | if (fls->cbyte >= fls->max) goto x_badresponse; |
| 76 | GET_B(fls->cbyte,lablen); |
| 77 | if (!(lablen & 0x0c0)) break; |
| 78 | if ((lablen & 0x0c0) != 0x0c0) return adns_s_unknownformat; |
| 79 | if (jumped++) { |
| 80 | adns__diag(fls->ads,fls->serv,fls->qu,"compressed datagram contains loop"); |
| 81 | return adns_s_invalidresponse; |
| 82 | } |
| 83 | if (fls->cbyte >= fls->dglen) goto x_truncated; |
| 84 | if (fls->cbyte >= fls->max) goto x_badresponse; |
| 85 | GET_B(fls->cbyte,jumpto); |
| 86 | jumpto |= (lablen&0x3f)<<8; |
| 87 | if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte; |
| 88 | fls->cbyte= jumpto; |
| 89 | fls->dmend_r= 0; fls->max= fls->dglen+1; |
| 90 | } |
| 91 | if (labstart_r) *labstart_r= fls->cbyte; |
| 92 | if (lablen) { |
| 93 | if (fls->namelen) fls->namelen++; |
| 94 | fls->namelen+= lablen; |
| 95 | if (fls->namelen > DNS_MAXDOMAIN) return adns_s_answerdomaintoolong; |
| 96 | fls->cbyte+= lablen; |
| 97 | if (fls->cbyte > fls->dglen) goto x_truncated; |
| 98 | if (fls->cbyte > fls->max) goto x_badresponse; |
| 99 | } else { |
| 100 | if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte; |
| 101 | } |
| 102 | *lablen_r= lablen; |
| 103 | /*if (labstart_r) fprintf(stderr,"label %d >%.*s<\n",lablen,lablen,fls->dgram+*labstart_r);*/ |
| 104 | return adns_s_ok; |
| 105 | |
| 106 | x_truncated: |
| 107 | *lablen_r= -1; |
| 108 | return adns_s_ok; |
| 109 | |
| 110 | x_badresponse: |
| 111 | adns__diag(fls->ads,fls->serv,fls->qu,"label in domain runs beyond end of domain"); |
| 112 | return adns_s_invalidresponse; |
| 113 | } |
| 114 | |
| 115 | adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu, |
| 116 | vbuf *vb, adns_queryflags flags, |
| 117 | const byte *dgram, int dglen, int *cbyte_io, int max) { |
| 118 | findlabel_state fls; |
| 119 | |
| 120 | int lablen, labstart, i, ch; |
| 121 | adns_status st; |
| 122 | |
| 123 | adns__findlabel_start(&fls,ads, serv,qu, dgram,dglen,max, *cbyte_io,cbyte_io); |
| 124 | vb->used= 0; |
| 125 | for (;;) { |
| 126 | st= adns__findlabel_next(&fls,&lablen,&labstart); |
| 127 | if (st) return st; |
| 128 | if (lablen<0) { vb->used=0; return adns_s_ok; } |
| 129 | if (!lablen) break; |
| 130 | if (vb->used) |
| 131 | if (!adns__vbuf_append(vb,".",1)) return adns_s_nomemory; |
| 132 | if (flags & pdf_quoteok) { |
| 133 | if (!vbuf__append_quoted1035(vb,dgram+labstart,lablen)) |
| 134 | return adns_s_nomemory; |
| 135 | } else { |
| 136 | ch= dgram[labstart]; |
| 137 | if (!ctype_alpha(ch) && !ctype_digit(ch)) return adns_s_answerdomaininvalid; |
| 138 | for (i= labstart+1; i<labstart+lablen; i++) { |
| 139 | ch= dgram[i]; |
| 140 | if (ch != '-' && !ctype_alpha(ch) && !ctype_digit(ch)) |
| 141 | return adns_s_answerdomaininvalid; |
| 142 | } |
| 143 | if (!adns__vbuf_append(vb,dgram+labstart,lablen)) |
| 144 | return adns_s_nomemory; |
| 145 | } |
| 146 | } |
| 147 | if (!adns__vbuf_append(vb,"",1)) return adns_s_nomemory; |
| 148 | return adns_s_ok; |
| 149 | } |
| 150 | |
| 151 | adns_status adns__findrr_anychk(adns_query qu, int serv, |
| 152 | const byte *dgram, int dglen, int *cbyte_io, |
| 153 | int *type_r, int *class_r, int *rdlen_r, int *rdstart_r, |
| 154 | const byte *eo_dgram, int eo_dglen, int eo_cbyte, |
| 155 | int *eo_matched_r) { |
| 156 | findlabel_state fls, eo_fls; |
| 157 | int cbyte; |
| 158 | |
| 159 | int tmp, rdlen, mismatch; |
| 160 | int lablen, labstart, ch; |
| 161 | int eo_lablen, eo_labstart, eo_ch; |
| 162 | adns_status st; |
| 163 | |
| 164 | cbyte= *cbyte_io; |
| 165 | |
| 166 | adns__findlabel_start(&fls,qu->ads, serv,qu, dgram,dglen,dglen,cbyte,&cbyte); |
| 167 | if (eo_dgram) { |
| 168 | adns__findlabel_start(&eo_fls,qu->ads, -1,0, eo_dgram,eo_dglen,eo_dglen,eo_cbyte,0); |
| 169 | mismatch= 0; |
| 170 | } else { |
| 171 | mismatch= 1; |
| 172 | } |
| 173 | |
| 174 | for (;;) { |
| 175 | st= adns__findlabel_next(&fls,&lablen,&labstart); |
| 176 | if (st) return st; |
| 177 | if (lablen<0) goto x_truncated; |
| 178 | |
| 179 | if (!mismatch) { |
| 180 | st= adns__findlabel_next(&eo_fls,&eo_lablen,&eo_labstart); |
| 181 | assert(!st); assert(eo_lablen>=0); |
| 182 | if (lablen != eo_lablen) mismatch= 1; |
| 183 | while (!mismatch && eo_lablen-- > 0) { |
| 184 | ch= dgram[labstart++]; if (ctype_alpha(ch)) ch &= ~32; |
| 185 | eo_ch= eo_dgram[eo_labstart++]; if (ctype_alpha(eo_ch)) eo_ch &= ~32; |
| 186 | if (ch != eo_ch) mismatch= 1; |
| 187 | } |
| 188 | } |
| 189 | if (!lablen) break; |
| 190 | } |
| 191 | if (eo_matched_r) *eo_matched_r= !mismatch; |
| 192 | |
| 193 | if (cbyte+10>dglen) goto x_truncated; |
| 194 | GET_W(cbyte,tmp); *type_r= tmp; |
| 195 | GET_W(cbyte,tmp); *class_r= tmp; |
| 196 | cbyte+= 4; /* we skip the TTL */ |
| 197 | GET_W(cbyte,rdlen); if (rdlen_r) *rdlen_r= rdlen; |
| 198 | if (rdstart_r) *rdstart_r= cbyte; |
| 199 | cbyte+= rdlen; |
| 200 | if (cbyte>dglen) goto x_truncated; |
| 201 | *cbyte_io= cbyte; |
| 202 | return adns_s_ok; |
| 203 | |
| 204 | x_truncated: |
| 205 | *type_r= -1; |
| 206 | return 0; |
| 207 | } |
| 208 | |
| 209 | adns_status adns__findrr(adns_query qu, int serv, |
| 210 | const byte *dgram, int dglen, int *cbyte_io, |
| 211 | int *type_r, int *class_r, int *rdlen_r, int *rdstart_r, |
| 212 | int *ownermatchedquery_r) { |
| 213 | if (!ownermatchedquery_r) { |
| 214 | return adns__findrr_anychk(qu,serv, |
| 215 | dgram,dglen,cbyte_io, |
| 216 | type_r,class_r,rdlen_r,rdstart_r, |
| 217 | 0,0,0, 0); |
| 218 | } else if (!qu->cname_dgram) { |
| 219 | return adns__findrr_anychk(qu,serv, |
| 220 | dgram,dglen,cbyte_io, |
| 221 | type_r,class_r,rdlen_r,rdstart_r, |
| 222 | qu->query_dgram,qu->query_dglen,DNS_HDRSIZE, |
| 223 | ownermatchedquery_r); |
| 224 | } else { |
| 225 | return adns__findrr_anychk(qu,serv, |
| 226 | dgram,dglen,cbyte_io, |
| 227 | type_r,class_r,rdlen_r,rdstart_r, |
| 228 | qu->cname_dgram,qu->cname_dglen,qu->cname_begin, |
| 229 | ownermatchedquery_r); |
| 230 | } |
| 231 | } |