| 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 == '$') { |
| 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 | buf+= i; len-= i; |
| 45 | } |
| 46 | return 1; |
| 47 | } |
| 48 | |
| 49 | void adns__findlabel_start(findlabel_state *fls, adns_state ads, |
| 50 | int serv, adns_query qu, |
| 51 | const byte *dgram, int dglen, int max, |
| 52 | int dmbegin, int *dmend_rlater) { |
| 53 | fls->ads= ads; |
| 54 | fls->qu= qu; |
| 55 | fls->serv= serv; |
| 56 | fls->dgram= dgram; |
| 57 | fls->dglen= dglen; |
| 58 | fls->max= max; |
| 59 | fls->cbyte= dmbegin; |
| 60 | fls->namelen= 0; |
| 61 | fls->dmend_r= dmend_rlater; |
| 62 | } |
| 63 | |
| 64 | adns_status adns__findlabel_next(findlabel_state *fls, |
| 65 | int *lablen_r, int *labstart_r) { |
| 66 | int lablen, jumped; |
| 67 | const char *dgram; |
| 68 | |
| 69 | jumped= 0; |
| 70 | dgram= fls->dgram; |
| 71 | for (;;) { |
| 72 | if (fls->cbyte+2 > fls->dglen) goto x_truncated; |
| 73 | if (fls->cbyte+2 > fls->max) goto x_serverfaulty; |
| 74 | GET_W(fls->cbyte,lablen); |
| 75 | if (!(lablen & 0x0c000)) break; |
| 76 | if ((lablen & 0x0c000) != 0x0c000) return adns_s_unknownreply; |
| 77 | if (jumped++) { |
| 78 | adns__diag(fls->ads,fls->serv,fls->qu,"compressed datagram contains loop"); |
| 79 | return adns_s_serverfaulty; |
| 80 | } |
| 81 | if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte; |
| 82 | fls->cbyte= DNS_HDRSIZE+(lablen&0x3fff); |
| 83 | fls->dmend_r= 0; fls->max= fls->dglen+1; |
| 84 | } |
| 85 | if (lablen) { |
| 86 | if (fls->namelen) fls->namelen++; |
| 87 | fls->namelen+= lablen; |
| 88 | if (fls->namelen > DNS_MAXDOMAIN) return adns_s_domaintoolong; |
| 89 | fls->cbyte+= lablen; |
| 90 | if (fls->cbyte > fls->dglen) goto x_truncated; |
| 91 | if (fls->cbyte > fls->max) goto x_serverfaulty; |
| 92 | } else { |
| 93 | if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte; |
| 94 | } |
| 95 | if (labstart_r) *labstart_r= fls->cbyte; |
| 96 | *lablen_r= lablen; |
| 97 | return adns_s_ok; |
| 98 | |
| 99 | x_truncated: |
| 100 | *lablen_r= -1; |
| 101 | return adns_s_ok; |
| 102 | |
| 103 | x_serverfaulty: |
| 104 | adns__diag(fls->ads,fls->serv,fls->qu,"label in domain runs beyond end of domain"); |
| 105 | return adns_s_serverfaulty; |
| 106 | } |
| 107 | |
| 108 | adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu, |
| 109 | vbuf *vb, int flags, |
| 110 | const byte *dgram, int dglen, int *cbyte_io, int max) { |
| 111 | findlabel_state fls; |
| 112 | |
| 113 | int lablen, labstart, i, ch; |
| 114 | adns_status st; |
| 115 | |
| 116 | adns__findlabel_start(&fls,ads, serv,qu, dgram,dglen,max, *cbyte_io,cbyte_io); |
| 117 | vb->used= 0; |
| 118 | for (;;) { |
| 119 | st= adns__findlabel_next(&fls,&lablen,&labstart); |
| 120 | if (st) return st; |
| 121 | if (lablen<0) { vb->used=0; return adns_s_ok; } |
| 122 | if (!lablen) break; |
| 123 | if (vb->used) |
| 124 | if (!adns__vbuf_append(vb,".",1)) return adns_s_nolocalmem; |
| 125 | if (flags & adns_qf_anyquote) { |
| 126 | if (!vbuf__append_quoted1035(vb,dgram+labstart,lablen)) |
| 127 | return adns_s_nolocalmem; |
| 128 | } else { |
| 129 | if (!ctype_alpha(dgram[labstart])) return adns_s_invaliddomain; |
| 130 | for (i= labstart+1; i<labstart+lablen; i++) { |
| 131 | ch= dgram[i]; |
| 132 | if (ch != '-' && !ctype_alpha(ch) && !ctype_digit(ch)) |
| 133 | return adns_s_invaliddomain; |
| 134 | } |
| 135 | if (!adns__vbuf_append(vb,dgram+labstart,lablen)) |
| 136 | return adns_s_nolocalmem; |
| 137 | } |
| 138 | } |
| 139 | if (!adns__vbuf_append(vb,"",1)) return adns_s_nolocalmem; |
| 140 | return adns_s_ok; |
| 141 | } |
| 142 | |
| 143 | static adns_status findrr_intern(adns_query qu, int serv, |
| 144 | const byte *dgram, int dglen, int *cbyte_io, |
| 145 | int *type_r, int *class_r, int *rdlen_r, int *rdstart_r, |
| 146 | const byte *eo_dgram, int eo_dglen, int eo_cbyte, |
| 147 | int *eo_matched_r) { |
| 148 | /* Like adns__findrr_checked, except that the datagram to compare |
| 149 | * with can be specified explicitly. |
| 150 | * |
| 151 | * If the caller thinks they know what the owner of the RR ought to |
| 152 | * be they can pass in details in eo_*: this is another (or perhaps |
| 153 | * the same datagram), and a pointer to where the putative owner |
| 154 | * starts in that datagram. In this case *eo_matched_r will be set |
| 155 | * to 1 if the datagram matched or 0 if it did not. Either |
| 156 | * both eo_dgram and eo_matched_r must both be non-null, or they |
| 157 | * must both be null (in which case eo_dglen and eo_cbyte will be ignored). |
| 158 | * The eo datagram and contained owner domain MUST be valid and |
| 159 | * untruncated. |
| 160 | */ |
| 161 | findlabel_state fls, eo_fls; |
| 162 | int cbyte; |
| 163 | |
| 164 | int tmp, rdlen, mismatch; |
| 165 | int lablen, labstart, ch; |
| 166 | int eo_lablen, eo_labstart, eo_ch; |
| 167 | adns_status st; |
| 168 | |
| 169 | cbyte= *cbyte_io; |
| 170 | |
| 171 | adns__findlabel_start(&fls,qu->ads, serv,qu, dgram,dglen,dglen,cbyte,&cbyte); |
| 172 | if (eo_dgram) { |
| 173 | adns__findlabel_start(&eo_fls,qu->ads, -1,0, eo_dgram,eo_dglen,eo_dglen,eo_cbyte,0); |
| 174 | mismatch= 0; |
| 175 | } else { |
| 176 | mismatch= 1; |
| 177 | } |
| 178 | |
| 179 | for (;;) { |
| 180 | st= adns__findlabel_next(&fls,&lablen,&labstart); |
| 181 | if (st) return st; |
| 182 | if (lablen<0) goto x_truncated; |
| 183 | |
| 184 | if (!mismatch) { |
| 185 | st= adns__findlabel_next(&eo_fls,&eo_lablen,&eo_labstart); |
| 186 | assert(!st); assert(eo_lablen>=0); |
| 187 | if (lablen != eo_lablen) mismatch= 1; |
| 188 | while (!mismatch && lablen-- > 0) { |
| 189 | ch= dgram[labstart++]; if (ctype_alpha(ch)) ch &= ~32; |
| 190 | eo_ch= eo_dgram[eo_labstart++]; if (ctype_alpha(eo_ch)) eo_ch &= ~32; |
| 191 | if (ch != eo_ch) mismatch= 1; |
| 192 | } |
| 193 | } |
| 194 | } |
| 195 | if (eo_matched_r) *eo_matched_r= !mismatch; |
| 196 | |
| 197 | if (cbyte+10>dglen) goto x_truncated; |
| 198 | GET_W(cbyte,tmp); *type_r= tmp; |
| 199 | GET_W(cbyte,tmp); *class_r= tmp; |
| 200 | cbyte+= 4; /* we skip the TTL */ |
| 201 | GET_W(cbyte,rdlen); if (rdlen_r) *rdlen_r= tmp; |
| 202 | if (rdstart_r) *rdstart_r= cbyte; |
| 203 | cbyte+= rdlen; |
| 204 | if (cbyte>dglen) goto x_truncated; |
| 205 | *cbyte_io= cbyte; |
| 206 | return adns_s_ok; |
| 207 | |
| 208 | x_truncated: |
| 209 | *type_r= -1; |
| 210 | return 0;; |
| 211 | } |
| 212 | |
| 213 | adns_status adns__findrr(adns_query qu, int serv, |
| 214 | const byte *dgram, int dglen, int *cbyte_io, |
| 215 | int *type_r, int *class_r, int *rdlen_r, int *rdstart_r, |
| 216 | int *ownermatchedquery_r) { |
| 217 | if (!ownermatchedquery_r) { |
| 218 | return findrr_intern(qu,serv, |
| 219 | dgram,dglen,cbyte_io, |
| 220 | type_r,class_r,rdlen_r,rdstart_r, |
| 221 | 0,0,0, 0); |
| 222 | } else if (!qu->cname_dgram) { |
| 223 | return findrr_intern(qu,serv, |
| 224 | dgram,dglen,cbyte_io, |
| 225 | type_r,class_r,rdlen_r,rdstart_r, |
| 226 | qu->query_dgram,qu->query_dglen,DNS_HDRSIZE, |
| 227 | ownermatchedquery_r); |
| 228 | } else { |
| 229 | return findrr_intern(qu,serv, |
| 230 | dgram,dglen,cbyte_io, |
| 231 | type_r,class_r,rdlen_r,rdstart_r, |
| 232 | qu->cname_dgram,qu->cname_dglen,qu->cname_begin, |
| 233 | ownermatchedquery_r); |
| 234 | } |
| 235 | } |