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import of dnsmasq-2.41.tar.gz

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This commit is contained in:
Simon Kelley
2008-02-12 20:43:05 +00:00
parent 5aabfc78bc
commit 824af85bdf
42 changed files with 8609 additions and 4729 deletions
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162
src/rfc1035.c
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@@ -1,13 +1,17 @@
/* dnsmasq is Copyright (c) 2000 - 2006 Simon Kelley
/* dnsmasq is Copyright (c) 2000-2007 Simon Kelley
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 dated June, 1991.
the Free Software Foundation; version 2 dated June, 1991, or
(at your option) version 3 dated 29 June, 2007.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "dnsmasq.h"
@@ -32,7 +36,7 @@ static int extract_name(HEADER *header, size_t plen, unsigned char **pp,
unsigned int label_type = l & 0xc0;
if (label_type == 0xc0) /* pointer */
{
if ((size_t)(p - (unsigned char *)header + 1) >= plen)
if ((size_t)(p - (unsigned char *)header) >= plen)
return 0;
/* get offset */
@@ -70,7 +74,7 @@ static int extract_name(HEADER *header, size_t plen, unsigned char **pp,
/* output is \[x<hex>/siz]. which is digs+9 chars */
if (cp - (unsigned char *)name + digs + 9 >= MAXDNAME)
return 0;
if ((size_t)(p - (unsigned char *)header + ((count-1)>>3) + 1) >= plen)
if ((size_t)(p - (unsigned char *)header + ((count-1)>>3)) >= plen)
return 0;
*cp++ = '\\';
@@ -94,7 +98,7 @@ static int extract_name(HEADER *header, size_t plen, unsigned char **pp,
{ /* label_type = 0 -> label. */
if (cp - (unsigned char *)name + l + 1 >= MAXDNAME)
return 0;
if ((size_t)(p - (unsigned char *)header + 1) >= plen)
if ((size_t)(p - (unsigned char *)header) >= plen)
return 0;
for(j=0; j<l; j++, p++)
if (isExtract)
@@ -497,6 +501,50 @@ static int private_net(struct in_addr addr)
((ip_addr & 0xFFFF0000) == 0xA9FE0000) /* 169.254.0.0/16 (zeroconf) */ ;
}
static unsigned char *do_doctor(unsigned char *p, int count, HEADER *header, size_t qlen)
{
int i, qtype, qclass, rdlen;
unsigned long ttl;
for (i = count; i != 0; i--)
{
if (!(p = skip_name(p, header, qlen)))
return 0; /* bad packet */
GETSHORT(qtype, p);
GETSHORT(qclass, p);
GETLONG(ttl, p);
GETSHORT(rdlen, p);
if ((qclass == C_IN) && (qtype == T_A))
{
struct doctor *doctor;
struct in_addr addr;
/* alignment */
memcpy(&addr, p, INADDRSZ);
for (doctor = daemon->doctors; doctor; doctor = doctor->next)
if (is_same_net(doctor->in, addr, doctor->mask))
{
addr.s_addr &= ~doctor->mask.s_addr;
addr.s_addr |= (doctor->out.s_addr & doctor->mask.s_addr);
/* Since we munged the data, the server it came from is no longer authoritative */
header->aa = 0;
memcpy(p, &addr, INADDRSZ);
break;
}
}
p += rdlen;
if ((size_t)(p - (unsigned char *)header) > qlen)
return 0; /* bad packet */
}
return p;
}
static int find_soa(HEADER *header, size_t qlen)
{
unsigned char *p;
@@ -506,8 +554,8 @@ static int find_soa(HEADER *header, size_t qlen)
/* first move to NS section and find TTL from any SOA section */
if (!(p = skip_questions(header, qlen)) ||
!(p = skip_section(p, ntohs(header->ancount), header, qlen)))
return 0; /* bad packet */
!(p = do_doctor(p, ntohs(header->ancount), header, qlen)))
return 0; /* bad packet */
for (i = ntohs(header->nscount); i != 0; i--)
{
@@ -544,52 +592,23 @@ static int find_soa(HEADER *header, size_t qlen)
return 0; /* bad packet */
}
if (daemon->doctors)
for (i = ntohs(header->arcount); i != 0; i--)
{
if (!(p = skip_name(p, header, qlen)))
return 0; /* bad packet */
GETSHORT(qtype, p);
GETSHORT(qclass, p);
GETLONG(ttl, p);
GETSHORT(rdlen, p);
if ((qclass == C_IN) && (qtype == T_A))
{
struct doctor *doctor;
struct in_addr addr;
/* alignment */
memcpy(&addr, p, INADDRSZ);
for (doctor = daemon->doctors; doctor; doctor = doctor->next)
if (is_same_net(doctor->in, addr, doctor->mask))
{
addr.s_addr &= ~doctor->mask.s_addr;
addr.s_addr |= (doctor->out.s_addr & doctor->mask.s_addr);
/* Since we munged the data, the server it came from is no longer authoritative */
header->aa = 0;
memcpy(p, &addr, INADDRSZ);
break;
}
}
p += rdlen;
if ((size_t)(p - (unsigned char *)header) > qlen)
return 0; /* bad packet */
}
return found_soa ? minttl : 0;
/* rewrite addresses in additioal section too */
if (!do_doctor(p, ntohs(header->arcount), header, qlen))
return 0;
if (!found_soa)
minttl = daemon->neg_ttl;
return minttl;
}
/* Note that the following code can create CNAME chains that don't point to a real record,
either because of lack of memory, or lack of SOA records. These are treated by the cache code as
expired and cleaned out that way. */
void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
expired and cleaned out that way.
Return 1 if we reject an address because it look like parct of dns-rebinding attack. */
int extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
{
unsigned char *p, *p1, *endrr;
unsigned char *p, *p1, *endrr, *namep;
int i, j, qtype, qclass, aqtype, aqclass, ardlen, res, searched_soa = 0;
unsigned long ttl = 0;
struct all_addr addr;
@@ -613,8 +632,9 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
int flags = header->rcode == NXDOMAIN ? F_NXDOMAIN : 0;
unsigned long cttl = ULONG_MAX, attl;
namep = p;
if (!extract_name(header, qlen, &p, name, 1))
return; /* bad packet */
return 0; /* bad packet */
GETSHORT(qtype, p);
GETSHORT(qclass, p);
@@ -635,12 +655,15 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
{
cname_loop:
if (!(p1 = skip_questions(header, qlen)))
return;
return 0;
for (j = ntohs(header->ancount); j != 0; j--)
{
if (!(res = extract_name(header, qlen, &p1, name, 0)))
return; /* bad packet */
unsigned char *tmp = namep;
/* the loop body overwrites the original name, so get it back here. */
if (!extract_name(header, qlen, &tmp, name, 1) ||
!(res = extract_name(header, qlen, &p1, name, 0)))
return 0; /* bad packet */
GETSHORT(aqtype, p1);
GETSHORT(aqclass, p1);
@@ -655,12 +678,12 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
if (aqclass == C_IN && res != 2 && (aqtype == T_CNAME || aqtype == T_PTR))
{
if (!extract_name(header, qlen, &p1, name, 1))
return;
return 0;
if (aqtype == T_CNAME)
{
if (!cname_count--)
return; /* looped CNAMES */
return 0; /* looped CNAMES */
goto cname_loop;
}
@@ -670,7 +693,7 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
p1 = endrr;
if ((size_t)(p1 - (unsigned char *)header) > qlen)
return; /* bad packet */
return 0; /* bad packet */
}
}
@@ -710,12 +733,12 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
{
cname_loop1:
if (!(p1 = skip_questions(header, qlen)))
return;
return 0;
for (j = ntohs(header->ancount); j != 0; j--)
{
if (!(res = extract_name(header, qlen, &p1, name, 0)))
return; /* bad packet */
return 0; /* bad packet */
GETSHORT(aqtype, p1);
GETSHORT(aqclass, p1);
@@ -728,7 +751,7 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
if (aqtype == T_CNAME)
{
if (!cname_count--)
return; /* looped CNAMES */
return 0; /* looped CNAMES */
newc = cache_insert(name, NULL, now, attl, F_CNAME | F_FORWARD);
if (newc && cpp)
{
@@ -741,7 +764,7 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
cttl = attl;
if (!extract_name(header, qlen, &p1, name, 1))
return;
return 0;
goto cname_loop1;
}
else
@@ -749,6 +772,13 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
found = 1;
/* copy address into aligned storage */
memcpy(&addr, p1, addrlen);
/* check for returned address in private space */
if ((daemon->options & OPT_NO_REBIND) &&
(flags & F_IPV4) &&
private_net(addr.addr.addr4))
return 1;
newc = cache_insert(name, &addr, now, attl, flags | F_FORWARD);
if (newc && cpp)
{
@@ -761,7 +791,7 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
p1 = endrr;
if ((size_t)(p1 - (unsigned char *)header) > qlen)
return; /* bad packet */
return 0; /* bad packet */
}
}
@@ -773,7 +803,7 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
ttl = find_soa(header, qlen);
}
/* If there's no SOA to get the TTL from, but there is a CNAME
pointing at this, inherit it's TTL */
pointing at this, inherit its TTL */
if (ttl || cpp)
{
newc = cache_insert(name, NULL, now, ttl ? ttl : cttl, F_FORWARD | F_NEG | flags);
@@ -787,7 +817,11 @@ void extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
}
}
cache_end_insert();
/* Don't put stuff from a truncated packet into the cache, but do everything else */
if (!header->tc)
cache_end_insert();
return 0;
}
/* If the packet holds exactly one query
@@ -844,7 +878,7 @@ size_t setup_reply(HEADER *header, size_t qlen,
header->ancount = htons(0); /* no answers unless changed below */
if (flags == F_NEG)
header->rcode = SERVFAIL; /* couldn't get memory */
else if (flags == F_NOERR || flags == F_QUERY)
else if (flags == F_NOERR)
header->rcode = NOERROR; /* empty domain */
else if (flags == F_NXDOMAIN)
header->rcode = NXDOMAIN;