src/patches/dnsmasq/0081-Handle-domain-names-with-.-or-000-within-labels.patch

   1 From cbe379ad6b52a538a4416a7cd992817e5637ccf9 Mon Sep 17 00:00:00 2001
   2 From: Simon Kelley <simon@thekelleys.org.uk>
   3 Date: Tue, 21 Apr 2015 22:57:06 +0100
   4 Subject: [PATCH 81/98] Handle domain names with '.' or /000 within labels.
   5
   6 Only in DNSSEC mode, where we might need to validate or store
   7 such names. In none-DNSSEC mode, simply don't cache these, as before.
   8 ---
   9  src/dns-protocol.h |  4 ++++
  10  src/dnsmasq.c      | 15 +++++++++++++--
  11  src/dnssec.c       | 40 +++++++++++++++++++++++++++++++---------
  12  src/rfc1035.c      | 16 +++++++++++++++-
  13  src/util.c         |  9 ++++++++-
  14  5 files changed, 71 insertions(+), 13 deletions(-)
  15
  16 diff --git a/src/dns-protocol.h b/src/dns-protocol.h
  17 index 16fade33d98c..7f5d686bb150 100644
  18 --- a/src/dns-protocol.h
  19 +++ b/src/dns-protocol.h
  20 @@ -142,3 +142,7 @@ struct dns_header {
  21
  22  #define ADD_RDLEN(header, pp, plen, len) \
  23    (!CHECK_LEN(header, pp, plen, len) ? 0 : (((pp) += (len)), 1))
  24 +
  25 +/* Escape character in our presentation format for names.
  26 +   Cannot be '.' or /000 and must be !isprint() */
  27 +#define NAME_ESCAPE 1
  28 diff --git a/src/dnsmasq.c b/src/dnsmasq.c
  29 index 20b15c05103a..19a6428b09e8 100644
  30 --- a/src/dnsmasq.c
  31 +++ b/src/dnsmasq.c
  32 @@ -102,8 +102,19 @@ int main (int argc, char **argv)
  33  #ifdef HAVE_DNSSEC
  34    if (option_bool(OPT_DNSSEC_VALID))
  35      {
  36 -      daemon->keyname = safe_malloc(MAXDNAME);
  37 -      daemon->workspacename = safe_malloc(MAXDNAME);
  38 +      /* Note that both /000 and '.' are allowed within labels. These get
  39 +        represented in presentation format using NAME_ESCAPE as an escape
  40 +        character when in DNSSEC mode.
  41 +        In theory, if all the characters in a name were /000 or
  42 +        '.' or NAME_ESCAPE then all would have to be escaped, so the
  43 +        presentation format would be twice as long as the spec.
  44 +
  45 +        daemon->namebuff was previously allocated by the option-reading
  46 +        code before we knew if we're in DNSSEC mode, so reallocate here. */
  47 +      free(daemon->namebuff);
  48 +      daemon->namebuff = safe_malloc(MAXDNAME * 2);
  49 +      daemon->keyname = safe_malloc(MAXDNAME * 2);
  50 +      daemon->workspacename = safe_malloc(MAXDNAME * 2);
  51      }
  52  #endif
  53
  54 diff --git a/src/dnssec.c b/src/dnssec.c
  55 index 05e0983cb251..c116a7b5f6f4 100644
  56 --- a/src/dnssec.c
  57 +++ b/src/dnssec.c
  58 @@ -321,10 +321,18 @@ static int verify(struct blockdata *key_data, unsigned int key_len, unsigned cha
  59     thus generating names in canonical form.
  60     Calling to_wire followed by from_wire is almost an identity,
  61     except that the UC remains mapped to LC.
  62 +
  63 +   Note that both /000 and '.' are allowed within labels. These get
  64 +   represented in presentation format using NAME_ESCAPE as an escape
  65 +   character. In theory, if all the characters in a name were /000 or
  66 +   '.' or NAME_ESCAPE then all would have to be escaped, so the
  67 +   presentation format would be twice as long as the spec (1024).
  68 +   The buffers are all delcared as 2049 (allowing for the trailing zero)
  69 +   for this reason.
  70  */
  71  static int to_wire(char *name)
  72  {
  73 -  unsigned char *l, *p, term;
  74 +  unsigned char *l, *p, *q, term;
  75    int len;
  76
  77    for (l = (unsigned char*)name; *l != 0; l = p)
  78 @@ -332,7 +340,10 @@ static int to_wire(char *name)
  79        for (p = l; *p != '.' && *p != 0; p++)
  80         if (*p >= 'A' && *p <= 'Z')
  81           *p = *p - 'A' + 'a';
  82 -
  83 +       else if (*p == NAME_ESCAPE)
  84 +         for (q = p; *q; q++)
  85 +             *q = *(q+1);
  86 +
  87        term = *p;
  88
  89        if ((len = p - l) != 0)
  90 @@ -351,13 +362,23 @@ static int to_wire(char *name)
  91  /* Note: no compression  allowed in input. */
  92  static void from_wire(char *name)
  93  {
  94 -  unsigned char *l;
  95 +  unsigned char *l, *p, *last;
  96    int len;
  97 -
  98 +
  99 +  for (last = (unsigned char *)name; *last != 0; last += *last+1);
 100 +
 101    for (l = (unsigned char *)name; *l != 0; l += len+1)
 102      {
 103        len = *l;
 104        memmove(l, l+1, len);
 105 +      for (p = l; p < l + len; p++)
 106 +       if (*p == '.' || *p == 0 || *p == NAME_ESCAPE)
 107 +         {
 108 +           memmove(p+1, p, 1 + last - p);
 109 +           len++;
 110 +           *p++ = NAME_ESCAPE;
 111 +         }
 112 +
 113        l[len] = '.';
 114      }
 115
 116 @@ -645,7 +666,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
 117               if (left1 != 0)
 118                 memmove(buff1, buff1 + len1 - left1, left1);
 119
 120 -             if ((len1 = get_rdata(header, plen, end1, buff1 + left1, MAXDNAME - left1, &p1, &dp1)) == 0)
 121 +             if ((len1 = get_rdata(header, plen, end1, buff1 + left1, (MAXDNAME * 2) - left1, &p1, &dp1)) == 0)
 122                 {
 123                   quit = 1;
 124                   len1 = end1 - p1;
 125 @@ -656,7 +677,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
 126               if (left2 != 0)
 127                 memmove(buff2, buff2 + len2 - left2, left2);
 128
 129 -             if ((len2 = get_rdata(header, plen, end2, buff2 + left2, MAXDNAME - left2, &p2, &dp2)) == 0)
 130 +             if ((len2 = get_rdata(header, plen, end2, buff2 + left2, (MAXDNAME *2) - left2, &p2, &dp2)) == 0)
 131                 {
 132                   quit = 1;
 133                   len2 = end2 - p2;
 134 @@ -902,10 +923,11 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
 135
 136           end = p + rdlen;
 137
 138 -         /* canonicalise rdata and calculate length of same, use name buffer as workspace */
 139 +         /* canonicalise rdata and calculate length of same, use name buffer as workspace.
 140 +            Note that name buffer is twice MAXDNAME long in DNSSEC mode. */
 141           cp = p;
 142           dp = rr_desc;
 143 -         for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)) != 0; len += seg);
 144 +         for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)) != 0; len += seg);
 145           len += end - cp;
 146           len = htons(len);
 147           hash->update(ctx, 2, (unsigned char *)&len);
 148 @@ -913,7 +935,7 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
 149           /* Now canonicalise again and digest. */
 150           cp = p;
 151           dp = rr_desc;
 152 -         while ((seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)))
 153 +         while ((seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)))
 154             hash->update(ctx, seg, (unsigned char *)name);
 155           if (cp != end)
 156             hash->update(ctx, end - cp, cp);
 157 diff --git a/src/rfc1035.c b/src/rfc1035.c
 158 index a995ab50d74a..19fecc818c06 100644
 159 --- a/src/rfc1035.c
 160 +++ b/src/rfc1035.c
 161 @@ -128,6 +128,15 @@ int extract_name(struct dns_header *header, size_t plen, unsigned char **pp,
 162             if (isExtract)
 163               {
 164                 unsigned char c = *p;
 165 +#ifdef HAVE_DNSSEC
 166 +               if (option_bool(OPT_DNSSEC_VALID))
 167 +                 {
 168 +                   if (c == 0 || c == '.' || c == NAME_ESCAPE)
 169 +                     *cp++ = NAME_ESCAPE;
 170 +                   *cp++ = c;
 171 +                 }
 172 +               else
 173 +#endif
 174                 if (c != 0 && c != '.')
 175                   *cp++ = c;
 176                 else
 177 @@ -144,9 +153,14 @@ int extract_name(struct dns_header *header, size_t plen, unsigned char **pp,
 178                     cp++;
 179                     if (c1 >= 'A' && c1 <= 'Z')
 180                       c1 += 'a' - 'A';
 181 +#ifdef HAVE_DNSSEC
 182 +                   if (option_bool(OPT_DNSSEC_VALID) && c1 == NAME_ESCAPE)
 183 +                     c1 = *cp++;
 184 +#endif
 185 +
 186                     if (c2 >= 'A' && c2 <= 'Z')
 187                       c2 += 'a' - 'A';
 188 -
 189 +
 190                     if (c1 != c2)
 191                       retvalue =  2;
 192                   }
 193 diff --git a/src/util.c b/src/util.c
 194 index 648bc4d4b428..0c1a48b4700a 100644
 195 --- a/src/util.c
 196 +++ b/src/util.c
 197 @@ -226,7 +226,14 @@ unsigned char *do_rfc1035_name(unsigned char *p, char *sval)
 198      {
 199        unsigned char *cp = p++;
 200        for (j = 0; *sval && (*sval != '.'); sval++, j++)
 201 -       *p++ = *sval;
 202 +       {
 203 +#ifdef HAVE_DNSSEC
 204 +         if (option_bool(OPT_DNSSEC_VALID) && *sval == NAME_ESCAPE)
 205 +           *p++ = *(++sval);
 206 +         else
 207 +#endif
 208 +           *p++ = *sval;
 209 +       }
 210        *cp  = j;
 211        if (*sval)
 212         sval++;
 213 --
 214 2.1.0
 215