Pi-Hole/dnsmasq
1
0
Fork 0
mirror of https://github.com/pi-hole/dnsmasq.git synced 2025-12-19 10:18:25 +00:00
Code Issues Packages Projects Releases Wiki Activity

import of dnsmasq-2.46.tar.gz

Browse Source
This commit is contained in:
Simon Kelley
2008-11-14 20:04:27 +00:00
parent 1ad24ae15c
commit 9009d74652
38 changed files with 4374 additions and 3918 deletions
Download Patch File Download Diff File Expand all files Collapse all files

245
src/rfc1035.c
View File

@@ -1,4 +1,4 @@
/* dnsmasq is Copyright (c) 2000-2007 Simon Kelley
/* dnsmasq is Copyright (c) 2000-2008 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
@@ -21,8 +21,14 @@ static int add_resource_record(HEADER *header, char *limit, int *truncp,
unsigned long ttl, unsigned int *offset, unsigned short type,
unsigned short class, char *format, ...);
#define CHECK_LEN(header, pp, plen, len) \
((size_t)((pp) - (unsigned char *)(header) + (len)) <= (plen))
#define ADD_RDLEN(header, pp, plen, len) \
(!CHECK_LEN(header, pp, plen, len) ? 0 : (int)((pp) += (len)), 1)
static int extract_name(HEADER *header, size_t plen, unsigned char **pp,
char *name, int isExtract)
char *name, int isExtract, int extrabytes)
{
unsigned char *cp = (unsigned char *)name, *p = *pp, *p1 = NULL;
unsigned int j, l, hops = 0;
@@ -31,19 +37,47 @@ static int extract_name(HEADER *header, size_t plen, unsigned char **pp,
if (isExtract)
*cp = 0;
while ((l = *p++))
{
unsigned int label_type = l & 0xc0;
while (1)
{
unsigned int label_type;
if (!CHECK_LEN(header, p, plen, 1))
return 0;
if ((l = *p++) == 0)
/* end marker */
{
/* check that there are the correct no of bytes after the name */
if (!CHECK_LEN(header, p, plen, extrabytes))
return 0;
if (isExtract)
{
if (cp != (unsigned char *)name)
cp--;
*cp = 0; /* terminate: lose final period */
}
else if (*cp != 0)
retvalue = 2;
if (p1) /* we jumped via compression */
*pp = p1;
else
*pp = p;
return retvalue;
}
label_type = l & 0xc0;
if (label_type == 0xc0) /* pointer */
{
if ((size_t)(p - (unsigned char *)header) >= plen)
if (!CHECK_LEN(header, p, plen, 1))
return 0;
/* get offset */
l = (l&0x3f) << 8;
l |= *p++;
if (l >= plen)
return 0;
if (!p1) /* first jump, save location to go back to */
p1 = p;
@@ -74,7 +108,7 @@ 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)) >= plen)
if (!CHECK_LEN(header, p, plen, (count-1)>>3))
return 0;
*cp++ = '\\';
@@ -98,8 +132,9 @@ 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) >= plen)
if (!CHECK_LEN(header, p, plen, l))
return 0;
for(j=0; j<l; j++, p++)
if (isExtract)
{
@@ -132,26 +167,7 @@ static int extract_name(HEADER *header, size_t plen, unsigned char **pp,
else if (*cp != 0 && *cp++ != '.')
retvalue = 2;
}
if ((unsigned int)(p - (unsigned char *)header) >= plen)
return 0;
}
if (isExtract)
{
if (cp != (unsigned char *)name)
cp--;
*cp = 0; /* terminate: lose final period */
}
else if (*cp != 0)
retvalue = 2;
if (p1) /* we jumped via compression */
*pp = p1;
else
*pp = p;
return retvalue;
}
/* Max size of input string (for IPv6) is 75 chars.) */
@@ -261,15 +277,17 @@ static int in_arpa_name_2_addr(char *namein, struct all_addr *addrp)
return 0;
}
static unsigned char *skip_name(unsigned char *ansp, HEADER *header, size_t plen)
static unsigned char *skip_name(unsigned char *ansp, HEADER *header, size_t plen, int extrabytes)
{
while(1)
{
unsigned int label_type = (*ansp) & 0xc0;
unsigned int label_type;
if ((unsigned int)(ansp - (unsigned char *)header) >= plen)
if (!CHECK_LEN(header, ansp, plen, 1))
return NULL;
label_type = (*ansp) & 0xc0;
if (label_type == 0xc0)
{
/* pointer for compression. */
@@ -283,6 +301,9 @@ static unsigned char *skip_name(unsigned char *ansp, HEADER *header, size_t plen
/* Extended label type */
unsigned int count;
if (!CHECK_LEN(header, ansp, plen, 2))
return NULL;
if (((*ansp++) & 0x3f) != 1)
return NULL; /* we only understand bitstrings */
@@ -296,12 +317,17 @@ static unsigned char *skip_name(unsigned char *ansp, HEADER *header, size_t plen
else
{ /* label type == 0 Bottom six bits is length */
unsigned int len = (*ansp++) & 0x3f;
if (!ADD_RDLEN(header, ansp, plen, len))
return NULL;
if (len == 0)
break; /* zero length label marks the end. */
ansp += len;
}
}
if (!CHECK_LEN(header, ansp, plen, extrabytes))
return NULL;
return ansp;
}
@@ -313,12 +339,10 @@ static unsigned char *skip_questions(HEADER *header, size_t plen)
for (q = ntohs(header->qdcount); q != 0; q--)
{
if (!(ansp = skip_name(ansp, header, plen)))
if (!(ansp = skip_name(ansp, header, plen, 4)))
return NULL;
ansp += 4; /* class and type */
}
if ((unsigned int)(ansp - (unsigned char *)header) > plen)
return NULL;
return ansp;
}
@@ -329,13 +353,12 @@ static unsigned char *skip_section(unsigned char *ansp, int count, HEADER *heade
for (i = 0; i < count; i++)
{
if (!(ansp = skip_name(ansp, header, plen)))
if (!(ansp = skip_name(ansp, header, plen, 10)))
return NULL;
ansp += 8; /* type, class, TTL */
GETSHORT(rdlen, ansp);
if ((unsigned int)(ansp + rdlen - (unsigned char *)header) > plen)
if (!ADD_RDLEN(header, ansp, plen, rdlen))
return NULL;
ansp += rdlen;
}
return ansp;
@@ -355,7 +378,7 @@ unsigned int questions_crc(HEADER *header, size_t plen, char *name)
for (q = ntohs(header->qdcount); q != 0; q--)
{
if (!extract_name(header, plen, &p, name, 1))
if (!extract_name(header, plen, &p, name, 1, 4))
return crc; /* bad packet */
for (p1 = (unsigned char *)name; *p1; p1++)
@@ -381,7 +404,7 @@ unsigned int questions_crc(HEADER *header, size_t plen, char *name)
}
p += 4;
if ((unsigned int)(p - (unsigned char *)header) > plen)
if (!CHECK_LEN(header, p, plen, 0))
return crc; /* bad packet */
}
@@ -393,12 +416,13 @@ size_t resize_packet(HEADER *header, size_t plen, unsigned char *pheader, size_t
{
unsigned char *ansp = skip_questions(header, plen);
/* if packet is malformed, just return as-is. */
if (!ansp)
return 0;
return plen;
if (!(ansp = skip_section(ansp, ntohs(header->ancount) + ntohs(header->nscount) + ntohs(header->arcount),
header, plen)))
return 0;
return plen;
/* restore pseudoheader */
if (pheader && ntohs(header->arcount) == 0)
@@ -432,7 +456,7 @@ unsigned char *find_pseudoheader(HEADER *header, size_t plen, size_t *len, unsi
{
for (i = ntohs(header->qdcount); i != 0; i--)
{
if (!(ansp = skip_name(ansp, header, plen)))
if (!(ansp = skip_name(ansp, header, plen, 4)))
return NULL;
GETSHORT(type, ansp);
@@ -458,7 +482,7 @@ unsigned char *find_pseudoheader(HEADER *header, size_t plen, size_t *len, unsi
for (i = 0; i < arcount; i++)
{
unsigned char *save, *start = ansp;
if (!(ansp = skip_name(ansp, header, plen)))
if (!(ansp = skip_name(ansp, header, plen, 10)))
return NULL;
GETSHORT(type, ansp);
@@ -466,9 +490,8 @@ unsigned char *find_pseudoheader(HEADER *header, size_t plen, size_t *len, unsi
GETSHORT(class, ansp);
ansp += 4; /* TTL */
GETSHORT(rdlen, ansp);
if ((size_t)(ansp + rdlen - (unsigned char *)header) > plen)
if (!ADD_RDLEN(header, ansp, plen, rdlen))
return NULL;
ansp += rdlen;
if (type == T_OPT)
{
if (len)
@@ -508,7 +531,7 @@ static unsigned char *do_doctor(unsigned char *p, int count, HEADER *header, siz
for (i = count; i != 0; i--)
{
if (!(p = skip_name(p, header, qlen)))
if (!(p = skip_name(p, header, qlen, 10)))
return 0; /* bad packet */
GETSHORT(qtype, p);
@@ -521,7 +544,10 @@ static unsigned char *do_doctor(unsigned char *p, int count, HEADER *header, siz
struct doctor *doctor;
struct in_addr addr;
/* alignment */
if (!CHECK_LEN(header, p, qlen, INADDRSZ))
return 0;
/* alignment */
memcpy(&addr, p, INADDRSZ);
for (doctor = daemon->doctors; doctor; doctor = doctor->next)
@@ -536,10 +562,8 @@ static unsigned char *do_doctor(unsigned char *p, int count, HEADER *header, siz
}
}
p += rdlen;
if ((size_t)(p - (unsigned char *)header) > qlen)
return 0; /* bad packet */
if (!ADD_RDLEN(header, p, qlen, rdlen))
return 0; /* bad packet */
}
return p;
@@ -559,7 +583,7 @@ static int find_soa(HEADER *header, size_t qlen)
for (i = ntohs(header->nscount); i != 0; i--)
{
if (!(p = skip_name(p, header, qlen)))
if (!(p = skip_name(p, header, qlen, 10)))
return 0; /* bad packet */
GETSHORT(qtype, p);
@@ -574,10 +598,10 @@ static int find_soa(HEADER *header, size_t qlen)
minttl = ttl;
/* MNAME */
if (!(p = skip_name(p, header, qlen)))
if (!(p = skip_name(p, header, qlen, 0)))
return 0;
/* RNAME */
if (!(p = skip_name(p, header, qlen)))
if (!(p = skip_name(p, header, qlen, 20)))
return 0;
p += 16; /* SERIAL REFRESH RETRY EXPIRE */
@@ -585,13 +609,10 @@ static int find_soa(HEADER *header, size_t qlen)
if (ttl < minttl)
minttl = ttl;
}
else
p += rdlen;
if ((size_t)(p - (unsigned char *)header) > qlen)
else if (!ADD_RDLEN(header, p, qlen, rdlen))
return 0; /* bad packet */
}
/* rewrite addresses in additioal section too */
if (!do_doctor(p, ntohs(header->arcount), header, qlen))
return 0;
@@ -633,7 +654,7 @@ int extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
unsigned long cttl = ULONG_MAX, attl;
namep = p;
if (!extract_name(header, qlen, &p, name, 1))
if (!extract_name(header, qlen, &p, name, 1, 4))
return 0; /* bad packet */
GETSHORT(qtype, p);
@@ -661,8 +682,8 @@ int extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
{
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)))
if (!extract_name(header, qlen, &tmp, name, 1, 0) ||
!(res = extract_name(header, qlen, &p1, name, 0, 10)))
return 0; /* bad packet */
GETSHORT(aqtype, p1);
@@ -677,7 +698,7 @@ int 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))
if (!extract_name(header, qlen, &p1, name, 1, 0))
return 0;
if (aqtype == T_CNAME)
@@ -692,7 +713,7 @@ int extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
}
p1 = endrr;
if ((size_t)(p1 - (unsigned char *)header) > qlen)
if (!CHECK_LEN(header, p1, qlen, 0))
return 0; /* bad packet */
}
}
@@ -737,7 +758,7 @@ int extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
for (j = ntohs(header->ancount); j != 0; j--)
{
if (!(res = extract_name(header, qlen, &p1, name, 0)))
if (!(res = extract_name(header, qlen, &p1, name, 0, 10)))
return 0; /* bad packet */
GETSHORT(aqtype, p1);
@@ -763,14 +784,17 @@ int extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
if (attl < cttl)
cttl = attl;
if (!extract_name(header, qlen, &p1, name, 1))
if (!extract_name(header, qlen, &p1, name, 1, 0))
return 0;
goto cname_loop1;
}
else
{
found = 1;
/* copy address into aligned storage */
if (!CHECK_LEN(header, p1, qlen, addrlen))
return 0; /* bad packet */
memcpy(&addr, p1, addrlen);
/* check for returned address in private space */
@@ -790,7 +814,7 @@ int extract_addresses(HEADER *header, size_t qlen, char *name, time_t now)
}
p1 = endrr;
if ((size_t)(p1 - (unsigned char *)header) > qlen)
if (!CHECK_LEN(header, p1, qlen, 0))
return 0; /* bad packet */
}
}
@@ -839,7 +863,7 @@ unsigned short extract_request(HEADER *header, size_t qlen, char *name, unsigned
if (ntohs(header->qdcount) != 1 || header->opcode != QUERY)
return 0; /* must be exactly one query. */
if (!extract_name(header, qlen, &p, name, 1))
if (!extract_name(header, qlen, &p, name, 1, 4))
return 0; /* bad packet */
GETSHORT(qtype, p);
@@ -953,7 +977,7 @@ int check_for_bogus_wildcard(HEADER *header, size_t qlen, char *name,
for (i = ntohs(header->ancount); i != 0; i--)
{
if (!extract_name(header, qlen, &p, name, 1))
if (!extract_name(header, qlen, &p, name, 1, 10))
return 0; /* bad packet */
GETSHORT(qtype, p);
@@ -962,19 +986,25 @@ int check_for_bogus_wildcard(HEADER *header, size_t qlen, char *name,
GETSHORT(rdlen, p);
if (qclass == C_IN && qtype == T_A)
for (baddrp = baddr; baddrp; baddrp = baddrp->next)
if (memcmp(&baddrp->addr, p, INADDRSZ) == 0)
{
/* Found a bogus address. Insert that info here, since there no SOA record
to get the ttl from in the normal processing */
cache_start_insert();
cache_insert(name, NULL, now, ttl, F_IPV4 | F_FORWARD | F_NEG | F_NXDOMAIN | F_CONFIG);
cache_end_insert();
return 1;
}
{
if (!CHECK_LEN(header, p, qlen, INADDRSZ))
return 0;
for (baddrp = baddr; baddrp; baddrp = baddrp->next)
if (memcmp(&baddrp->addr, p, INADDRSZ) == 0)
{
/* Found a bogus address. Insert that info here, since there no SOA record
to get the ttl from in the normal processing */
cache_start_insert();
cache_insert(name, NULL, now, ttl, F_IPV4 | F_FORWARD | F_NEG | F_NXDOMAIN | F_CONFIG);
cache_end_insert();
return 1;
}
}
p += rdlen;
if (!ADD_RDLEN(header, p, qlen, rdlen))
return 0;
}
return 0;
@@ -1073,6 +1103,18 @@ static int add_resource_record(HEADER *header, char *limit, int *truncp, unsigne
return 1;
}
static unsigned long crec_ttl(struct crec *crecp, time_t now)
{
/* Return 0 ttl for DHCP entries, which might change
before the lease expires. */
if (crecp->flags & (F_IMMORTAL | F_DHCP))
return daemon->local_ttl;
return crecp->ttd - now;
}
/* return zero if we can't answer from cache, or packet size if we can */
size_t answer_request(HEADER *header, char *limit, size_t qlen,
struct in_addr local_addr, struct in_addr local_netmask, time_t now)
@@ -1137,7 +1179,7 @@ size_t answer_request(HEADER *header, char *limit, size_t qlen,
nameoffset = p - (unsigned char *)header;
/* now extract name as .-concatenated string into name */
if (!extract_name(header, qlen, &p, name, 1))
if (!extract_name(header, qlen, &p, name, 1, 4))
return 0; /* bad packet */
GETSHORT(qtype, p);
@@ -1239,18 +1281,11 @@ size_t answer_request(HEADER *header, char *limit, size_t qlen,
auth = 0;
if (!dryrun)
{
unsigned long ttl;
/* Return 0 ttl for DHCP entries, which might change
before the lease expires. */
if (crecp->flags & (F_IMMORTAL | F_DHCP))
ttl = daemon->local_ttl;
else
ttl = crecp->ttd - now;
log_query(crecp->flags & ~F_FORWARD, cache_get_name(crecp), &addr,
record_source(daemon->addn_hosts, crecp->uid));
if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, ttl, NULL,
if (add_resource_record(header, limit, &trunc, nameoffset, &ansp,
crec_ttl(crecp, now), NULL,
T_PTR, C_IN, "d", cache_get_name(crecp)))
anscount++;
}
@@ -1358,7 +1393,8 @@ size_t answer_request(HEADER *header, char *limit, size_t qlen,
if (!dryrun)
{
log_query(crecp->flags, name, NULL, record_source(daemon->addn_hosts, crecp->uid));
if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, crecp->ttd - now, &nameoffset,
if (add_resource_record(header, limit, &trunc, nameoffset, &ansp,
crec_ttl(crecp, now), &nameoffset,
T_CNAME, C_IN, "d", cache_get_name(crecp->addr.cname.cache)))
anscount++;
}
@@ -1391,17 +1427,11 @@ size_t answer_request(HEADER *header, char *limit, size_t qlen,
ans = 1;
if (!dryrun)
{
unsigned long ttl;
if (crecp->flags & (F_IMMORTAL | F_DHCP))
ttl = daemon->local_ttl;
else
ttl = crecp->ttd - now;
log_query(crecp->flags & ~F_REVERSE, name, &crecp->addr.addr,
record_source(daemon->addn_hosts, crecp->uid));
if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, ttl, NULL, type, C_IN,
if (add_resource_record(header, limit, &trunc, nameoffset, &ansp,
crec_ttl(crecp, now), NULL, type, C_IN,
type == T_A ? "4" : "6", &crecp->addr))
anscount++;
}
@@ -1529,7 +1559,6 @@ size_t answer_request(HEADER *header, char *limit, size_t qlen,
crecp = NULL;
while ((crecp = cache_find_by_name(crecp, rec->target, now, F_IPV4 | F_IPV6)))
{
unsigned long ttl;
#ifdef HAVE_IPV6
int type = crecp->flags & F_IPV4 ? T_A : T_AAAA;
#else
@@ -1538,12 +1567,8 @@ size_t answer_request(HEADER *header, char *limit, size_t qlen,
if (crecp->flags & F_NEG)
continue;
if (crecp->flags & (F_IMMORTAL | F_DHCP))
ttl = daemon->local_ttl;
else
ttl = crecp->ttd - now;
if (add_resource_record(header, limit, NULL, rec->offset, &ansp, ttl, NULL, type, C_IN,
if (add_resource_record(header, limit, NULL, rec->offset, &ansp,
crec_ttl(crecp, now), NULL, type, C_IN,
crecp->flags & F_IPV4 ? "4" : "6", &crecp->addr))
addncount++;
}