diff --git a/src/utils_dns.c b/src/utils_dns.c
index 2348be24db05d55c5b1d6b6ad000ce8108594701..22c9b95994377f9ed1752d4192eb25c29a97b8e8 100644 (file)
--- a/src/utils_dns.c
+++ b/src/utils_dns.c
@@ -291,13 +291,18 @@ rfc1035NameUnpack(const char *buf, size_t sz, off_t * off, char *name, size_t ns
off_t no = 0;
unsigned char c;
size_t len;
off_t no = 0;
unsigned char c;
size_t len;
- assert(ns > 0);
+ static int loop_detect = 0;
+ if (loop_detect > 2)
+ return 4; /* compression loop */
+ if (ns <= 0)
+ return 4; /* probably compression loop */
do {
if ((*off) >= sz)
break;
c = *(buf + (*off));
if (c > 191) {
/* blasted compression */
do {
if ((*off) >= sz)
break;
c = *(buf + (*off));
if (c > 191) {
/* blasted compression */
+ int rc;
unsigned short s;
off_t ptr;
memcpy(&s, buf + (*off), sizeof(s));
unsigned short s;
off_t ptr;
memcpy(&s, buf + (*off), sizeof(s));
@@ -305,18 +310,23 @@ rfc1035NameUnpack(const char *buf, size_t sz, off_t * off, char *name, size_t ns
(*off) += sizeof(s);
/* Sanity check */
if ((*off) >= sz)
(*off) += sizeof(s);
/* Sanity check */
if ((*off) >= sz)
- return 1;
+ return 1; /* message too short */
ptr = s & 0x3FFF;
/* Make sure the pointer is inside this message */
if (ptr >= sz)
ptr = s & 0x3FFF;
/* Make sure the pointer is inside this message */
if (ptr >= sz)
- return 2;
- return rfc1035NameUnpack(buf, sz, &ptr, name + no, ns - no);
+ return 2; /* bad compression ptr */
+ if (ptr < DNS_MSG_HDR_SZ)
+ return 2; /* bad compression ptr */
+ loop_detect++;
+ rc = rfc1035NameUnpack(buf, sz, &ptr, name + no, ns - no);
+ loop_detect--;
+ return rc;
} else if (c > RFC1035_MAXLABELSZ) {
/*
* "(The 10 and 01 combinations are reserved for future use.)"
*/
} else if (c > RFC1035_MAXLABELSZ) {
/*
* "(The 10 and 01 combinations are reserved for future use.)"
*/
+ return 3; /* reserved label/compression flags */
break;
break;
- return 3;
} else {
(*off)++;
len = (size_t) c;
} else {
(*off)++;
len = (size_t) c;
@@ -324,15 +334,18 @@ rfc1035NameUnpack(const char *buf, size_t sz, off_t * off, char *name, size_t ns
break;
if (len > (ns - 1))
len = ns - 1;
break;
if (len > (ns - 1))
len = ns - 1;
- if ((*off) + len > sz) /* message is too short */
- return 4;
+ if ((*off) + len > sz)
+ return 4; /* message is too short */
+ if (no + len + 1 > ns)
+ return 5; /* qname would overflow name buffer */
memcpy(name + no, buf + (*off), len);
(*off) += len;
no += len;
*(name + (no++)) = '.';
}
} while (c > 0);
memcpy(name + no, buf + (*off), len);
(*off) += len;
no += len;
*(name + (no++)) = '.';
}
} while (c > 0);
- *(name + no - 1) = '\0';
+ if (no > 0)
+ *(name + no - 1) = '\0';
/* make sure we didn't allow someone to overflow the name buffer */
assert(no <= ns);
return 0;
/* make sure we didn't allow someone to overflow the name buffer */
assert(no <= ns);
return 0;
uint16_t us;
off_t offset;
char *t;
uint16_t us;
off_t offset;
char *t;
- int x;
+ int status;
/* The DNS header is 12 bytes long */
/* The DNS header is 12 bytes long */
- if (len < 12)
+ if (len < DNS_MSG_HDR_SZ)
return 0;
memcpy(&us, buf + 0, 2);
return 0;
memcpy(&us, buf + 0, 2);
memcpy(&us, buf + 10, 2);
qh.arcount = ntohs(us);
memcpy(&us, buf + 10, 2);
qh.arcount = ntohs(us);
- offset = 12;
+ offset = DNS_MSG_HDR_SZ;
memset(qh.qname, '\0', MAX_QNAME_SZ);
memset(qh.qname, '\0', MAX_QNAME_SZ);
- x = rfc1035NameUnpack(buf, len, &offset, qh.qname, MAX_QNAME_SZ);
- if (0 != x)
+ status = rfc1035NameUnpack(buf, len, &offset, qh.qname, MAX_QNAME_SZ);
+ if (status != 0)
+ {
+ INFO ("utils_dns: handle_dns: rfc1035NameUnpack failed "
+ "with status %i.", status);
return 0;
return 0;
+ }
if ('\0' == qh.qname[0])
sstrncpy (qh.qname, ".", sizeof (qh.qname));
while ((t = strchr(qh.qname, '\n')))
if ('\0' == qh.qname[0])
sstrncpy (qh.qname, ".", sizeof (qh.qname));
while ((t = strchr(qh.qname, '\n')))
@@ -647,10 +664,6 @@ void handle_pcap(u_char *udata, const struct pcap_pkthdr *hdr, const u_char *pkt
{
int status;
{
int status;
- DEBUG ("handle_pcap (udata = %p, hdr = %p, pkt = %p): hdr->caplen = %i\n",
- (void *) udata, (void *) hdr, (void *) pkt,
- hdr->caplen);
-
if (hdr->caplen < ETHER_HDR_LEN)
return;
if (hdr->caplen < ETHER_HDR_LEN)
return;
@@ -684,7 +697,7 @@ void handle_pcap(u_char *udata, const struct pcap_pkthdr *hdr, const u_char *pkt
break;
default:
break;
default:
- ERROR ("handle_pcap: unsupported data link type %d\n",
+ ERROR ("handle_pcap: unsupported data link type %d",
pcap_datalink(pcap_obj));
status = 0;
break;
pcap_datalink(pcap_obj));
status = 0;
break;