src/patches/dnsmasq/dnsmasq-2.73-fix-crash-in-DNSSEC-code-when-attempting-to-verify-large-RRs.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] Fix crash in DNSSEC code when attempting to verify large
   5  RRs.
   6
   7 ---
   8  src/dnssec.c |   27 +++++++++++++++++++--------
   9  1 files changed, 22 insertions(+), 8 deletions(-)
  10
  11 diff --git a/src/dnssec.c b/src/dnssec.c
  12 index 69bfc29..3208ac7 100644
  13 --- a/src/dnssec.c
  14 +++ b/src/dnssec.c
  15 @@ -456,16 +456,27 @@ static u16 *get_desc(int type)
  16
  17  /* Return bytes of canonicalised rdata, when the return value is zero, the remaining
  18     data, pointed to by *p, should be used raw. */
  19 -static int get_rdata(struct dns_header *header, size_t plen, unsigned char *end, char *buff,
  20 +static int get_rdata(struct dns_header *header, size_t plen, unsigned char *end, char *buff, int bufflen,
  21                      unsigned char **p, u16 **desc)
  22  {
  23    int d = **desc;
  24
  25 -  (*desc)++;
  26 -
  27    /* No more data needs mangling */
  28    if (d == (u16)-1)
  29 -    return 0;
  30 +    {
  31 +      /* If there's more data than we have space for, just return what fits,
  32 +        we'll get called again for more chunks */
  33 +      if (end - *p > bufflen)
  34 +       {
  35 +         memcpy(buff, *p, bufflen);
  36 +         *p += bufflen;
  37 +         return bufflen;
  38 +       }
  39 +
  40 +      return 0;
  41 +    }
  42 +
  43 +  (*desc)++;
  44
  45    if (d == 0 && extract_name(header, plen, p, buff, 1, 0))
  46      /* domain-name, canonicalise */
  47 @@ -560,7 +571,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
  48               if (left1 != 0)
  49                 memmove(buff1, buff1 + len1 - left1, left1);
  50
  51 -             if ((len1 = get_rdata(header, plen, end1, buff1 + left1, &p1, &dp1)) == 0)
  52 +             if ((len1 = get_rdata(header, plen, end1, buff1 + left1, MAXDNAME - left1, &p1, &dp1)) == 0)
  53                 {
  54                   quit = 1;
  55                   len1 = end1 - p1;
  56 @@ -571,7 +582,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
  57               if (left2 != 0)
  58                 memmove(buff2, buff2 + len2 - left2, left2);
  59
  60 -             if ((len2 = get_rdata(header, plen, end2, buff2 + left2, &p2, &dp2)) == 0)
  61 +             if ((len2 = get_rdata(header, plen, end2, buff2 + left2, MAXDNAME - left2, &p2, &dp2)) == 0)
  62                 {
  63                   quit = 1;
  64                   len2 = end2 - p2;
  65 @@ -808,7 +819,7 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
  66           /* canonicalise rdata and calculate length of same, use name buffer as workspace */
  67           cp = p;
  68           dp = rr_desc;
  69 -         for (len = 0; (seg = get_rdata(header, plen, end, name, &cp, &dp)) != 0; len += seg);
  70 +         for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)) != 0; len += seg);
  71           len += end - cp;
  72           len = htons(len);
  73           hash->update(ctx, 2, (unsigned char *)&len);
  74 @@ -816,7 +827,7 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
  75           /* Now canonicalise again and digest. */
  76           cp = p;
  77           dp = rr_desc;
  78 -         while ((seg = get_rdata(header, plen, end, name, &cp, &dp)))
  79 +         while ((seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)))
  80             hash->update(ctx, seg, (unsigned char *)name);
  81           if (cp != end)
  82             hash->update(ctx, end - cp, cp);
  83 --
  84 1.7.10.4
  85