src/patches/dnsmasq/0017-Fix-crash-in-DNSSEC-code-when-attempting-to-verify-l.patch

   1 From 094b5c3d904bae9aeb3206d9f3b8348926b84975 Mon Sep 17 00:00:00 2001
   2 From: Simon Kelley <simon@thekelleys.org.uk>
   3 Date: Sun, 21 Dec 2014 16:11:52 +0000
   4 Subject: [PATCH 17/87] Fix crash in DNSSEC code when attempting to verify
   5  large RRs.
   6
   7 ---
   8  CHANGELOG    |  3 +++
   9  src/dnssec.c | 27 +++++++++++++++++++--------
  10  2 files changed, 22 insertions(+), 8 deletions(-)
  11
  12 diff --git a/CHANGELOG b/CHANGELOG
  13 index 01f5208ec006..956b71a151db 100644
  14 --- a/CHANGELOG
  15 +++ b/CHANGELOG
  16 @@ -19,6 +19,9 @@ version 2.73
  17             the answers given by --interface-name. Note that reverse queries
  18             (ie looking for names, given addresses) are not affected.
  19             Thanks to Michael Gorbach for the suggestion.
  20 +
  21 +           Fix crash in DNSSEC code with long RRs. Thanks to Marco Davids
  22 +           for the bug report.
  23
  24
  25  version 2.72
  26 diff --git a/src/dnssec.c b/src/dnssec.c
  27 index 69bfc29e355f..3208ac701149 100644
  28 --- a/src/dnssec.c
  29 +++ b/src/dnssec.c
  30 @@ -456,16 +456,27 @@ static u16 *get_desc(int type)
  31
  32  /* Return bytes of canonicalised rdata, when the return value is zero, the remaining
  33     data, pointed to by *p, should be used raw. */
  34 -static int get_rdata(struct dns_header *header, size_t plen, unsigned char *end, char *buff,
  35 +static int get_rdata(struct dns_header *header, size_t plen, unsigned char *end, char *buff, int bufflen,
  36                      unsigned char **p, u16 **desc)
  37  {
  38    int d = **desc;
  39
  40 -  (*desc)++;
  41 -
  42    /* No more data needs mangling */
  43    if (d == (u16)-1)
  44 -    return 0;
  45 +    {
  46 +      /* If there's more data than we have space for, just return what fits,
  47 +        we'll get called again for more chunks */
  48 +      if (end - *p > bufflen)
  49 +       {
  50 +         memcpy(buff, *p, bufflen);
  51 +         *p += bufflen;
  52 +         return bufflen;
  53 +       }
  54 +
  55 +      return 0;
  56 +    }
  57 +
  58 +  (*desc)++;
  59
  60    if (d == 0 && extract_name(header, plen, p, buff, 1, 0))
  61      /* domain-name, canonicalise */
  62 @@ -560,7 +571,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
  63               if (left1 != 0)
  64                 memmove(buff1, buff1 + len1 - left1, left1);
  65
  66 -             if ((len1 = get_rdata(header, plen, end1, buff1 + left1, &p1, &dp1)) == 0)
  67 +             if ((len1 = get_rdata(header, plen, end1, buff1 + left1, MAXDNAME - left1, &p1, &dp1)) == 0)
  68                 {
  69                   quit = 1;
  70                   len1 = end1 - p1;
  71 @@ -571,7 +582,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
  72               if (left2 != 0)
  73                 memmove(buff2, buff2 + len2 - left2, left2);
  74
  75 -             if ((len2 = get_rdata(header, plen, end2, buff2 + left2, &p2, &dp2)) == 0)
  76 +             if ((len2 = get_rdata(header, plen, end2, buff2 + left2, MAXDNAME - left2, &p2, &dp2)) == 0)
  77                 {
  78                   quit = 1;
  79                   len2 = end2 - p2;
  80 @@ -808,7 +819,7 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
  81           /* canonicalise rdata and calculate length of same, use name buffer as workspace */
  82           cp = p;
  83           dp = rr_desc;
  84 -         for (len = 0; (seg = get_rdata(header, plen, end, name, &cp, &dp)) != 0; len += seg);
  85 +         for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)) != 0; len += seg);
  86           len += end - cp;
  87           len = htons(len);
  88           hash->update(ctx, 2, (unsigned char *)&len);
  89 @@ -816,7 +827,7 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
  90           /* Now canonicalise again and digest. */
  91           cp = p;
  92           dp = rr_desc;
  93 -         while ((seg = get_rdata(header, plen, end, name, &cp, &dp)))
  94 +         while ((seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)))
  95             hash->update(ctx, seg, (unsigned char *)name);
  96           if (cp != end)
  97             hash->update(ctx, end - cp, cp);
  98 --
  99 2.1.0
 100