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Handle domain names with '.' or /000 within labels.

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Only in DNSSEC mode, where we might need to validate or store
such names. In none-DNSSEC mode, simply don't cache these, as before.
This commit is contained in:
Simon Kelley
2015-04-21 22:57:06 +01:00
parent 338b340be9
commit cbe379ad6b
5 changed files with 71 additions and 13 deletions
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40
src/dnssec.c
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@@ -321,10 +321,18 @@ static int verify(struct blockdata *key_data, unsigned int key_len, unsigned cha
thus generating names in canonical form.
Calling to_wire followed by from_wire is almost an identity,
except that the UC remains mapped to LC.
Note that both /000 and '.' are allowed within labels. These get
represented in presentation format using NAME_ESCAPE as an escape
character. In theory, if all the characters in a name were /000 or
'.' or NAME_ESCAPE then all would have to be escaped, so the
presentation format would be twice as long as the spec (1024).
The buffers are all delcared as 2049 (allowing for the trailing zero)
for this reason.
*/
static int to_wire(char *name)
{
unsigned char *l, *p, term;
unsigned char *l, *p, *q, term;
int len;
for (l = (unsigned char*)name; *l != 0; l = p)
@@ -332,7 +340,10 @@ static int to_wire(char *name)
for (p = l; *p != '.' && *p != 0; p++)
if (*p >= 'A' && *p <= 'Z')
*p = *p - 'A' + 'a';
else if (*p == NAME_ESCAPE)
for (q = p; *q; q++)
*q = *(q+1);
term = *p;
if ((len = p - l) != 0)
@@ -351,13 +362,23 @@ static int to_wire(char *name)
/* Note: no compression allowed in input. */
static void from_wire(char *name)
{
unsigned char *l;
unsigned char *l, *p, *last;
int len;
for (last = (unsigned char *)name; *last != 0; last += *last+1);
for (l = (unsigned char *)name; *l != 0; l += len+1)
{
len = *l;
memmove(l, l+1, len);
for (p = l; p < l + len; p++)
if (*p == '.' || *p == 0 || *p == NAME_ESCAPE)
{
memmove(p+1, p, 1 + last - p);
len++;
*p++ = NAME_ESCAPE;
}
l[len] = '.';
}
@@ -645,7 +666,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
if (left1 != 0)
memmove(buff1, buff1 + len1 - left1, left1);
if ((len1 = get_rdata(header, plen, end1, buff1 + left1, MAXDNAME - left1, &p1, &dp1)) == 0)
if ((len1 = get_rdata(header, plen, end1, buff1 + left1, (MAXDNAME * 2) - left1, &p1, &dp1)) == 0)
{
quit = 1;
len1 = end1 - p1;
@@ -656,7 +677,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
if (left2 != 0)
memmove(buff2, buff2 + len2 - left2, left2);
if ((len2 = get_rdata(header, plen, end2, buff2 + left2, MAXDNAME - left2, &p2, &dp2)) == 0)
if ((len2 = get_rdata(header, plen, end2, buff2 + left2, (MAXDNAME *2) - left2, &p2, &dp2)) == 0)
{
quit = 1;
len2 = end2 - p2;
@@ -902,10 +923,11 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
end = p + rdlen;
/* canonicalise rdata and calculate length of same, use name buffer as workspace */
/* canonicalise rdata and calculate length of same, use name buffer as workspace.
Note that name buffer is twice MAXDNAME long in DNSSEC mode. */
cp = p;
dp = rr_desc;
for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)) != 0; len += seg);
for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)) != 0; len += seg);
len += end - cp;
len = htons(len);
hash->update(ctx, 2, (unsigned char *)&len);
@@ -913,7 +935,7 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
/* Now canonicalise again and digest. */
cp = p;
dp = rr_desc;
while ((seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)))
while ((seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)))
hash->update(ctx, seg, (unsigned char *)name);
if (cp != end)
hash->update(ctx, end - cp, cp);