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Fix some bugs:

Browse Source 
- Don't dereference a NULL hostent pointer (if T_PTR lookup fails).

- Today I asked myself: "Self, you wrote this nifty async resolver
  that does a great job handling delayed replies to clients using
  the UDP transport, and the yplib code in libc always uses UDP
  (except for yp_all()). But what if some dork makes a DNS lookup using
  TCP?" Being the only dork on hand at the time, I tried it and was
  enlightened. As I suspected, my transaction ID frobbing hacks cause
  fireworks if called on a TCP transport handle (duh: the structures
  are different). Fix: check the type of socket in xprt->xp_sock using
  getsockopt() and don't use svcudp_get_xid() and svcudp_set_xid() for
  anything except SOCK_DGRAM sockets. (Since accept() gives you a
  new socket for each connection, the transaction ID munging isn't
  needed for TCP anyway.)
This commit is contained in:
Bill Paul 1996-12-24 02:44:52 +00:00
parent 6b73680dcf
commit 926f037af9
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=20893
1 changed files with 34 additions and 11 deletions
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45
usr.sbin/ypserv/yp_dnslookup.c
View File

@ -29,7 +29,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: yp_dnslookup.c,v 1.5 1996/12/22 15:45:33 wpaul Exp $
* $Id: yp_dnslookup.c,v 1.4 1996/12/22 22:30:54 wpaul Exp $
*/
/*
@ -65,7 +65,7 @@
#include "yp_extern.h"
#ifndef lint
static const char rcsid[] = "$Id: yp_dnslookup.c,v 1.5 1996/12/22 15:45:33 wpaul Exp $";
static const char rcsid[] = "$Id: yp_dnslookup.c,v 1.4 1996/12/22 22:30:54 wpaul Exp $";
#endif
static char *parse(hp)
@ -110,6 +110,7 @@ struct circleq_dnsentry {
unsigned long ttl;
unsigned long sent;
unsigned long type;
unsigned short prot_type;
char **domain;
char *name;
struct in_addr addr;
@ -243,12 +244,17 @@ static void yp_send_dns_reply(q, buf)
* way we found 'em. This is _INCREDIBLY_ non-portable; it's
* not even supported by the RPC library.
*/
xid = svcudp_set_xid(q->xprt, q->xid);
/*
* XXX Don't from the transaction ID for TCP handles.
*/
if (q->prot_type == SOCK_DGRAM)
xid = svcudp_set_xid(q->xprt, q->xid);
client_addr = q->xprt->xp_raddr;
q->xprt->xp_raddr = q->client_addr;
if (!svc_sendreply(q->xprt, xdr_ypresp_val, (char *)&result))
yp_error("svc_sendreply failed");
svcudp_set_xid(q->xprt, xid);
if (q->prot_type == SOCK_DGRAM)
svcudp_set_xid(q->xprt, xid);
q->xprt->xp_raddr = client_addr;
return;
}
@ -311,7 +317,7 @@ void yp_run_dnsq()
if (hent == NULL) {
char retrybuf[MAXHOSTNAMELEN];
if (q->domain && *q->domain) {
if (h_errno == TRY_AGAIN && q->domain && *q->domain) {
snprintf(retrybuf, sizeof(retrybuf), "%s.%s",
q->name, *q->domain);
if (debug)
@ -321,12 +327,13 @@ void yp_run_dnsq()
q->domain++;
return;
}
} else {
if (q->type == T_PTR) {
hent->h_addr = (char *)&q->addr.s_addr;
hent->h_length = sizeof(struct in_addr);
}
}
if (q->type == T_PTR) {
hent->h_addr = (char *)&q->addr.s_addr;
hent->h_length = sizeof(struct in_addr);
}
yp_send_dns_reply(q, parse(hent));
pending--;
@ -344,6 +351,7 @@ ypstat yp_async_lookup_name(xprt, name)
char *name;
{
register struct circleq_dnsentry *q;
int type, len;
if ((q = yp_malloc_dnsent()) == NULL)
return(YP_YPERR);
@ -352,7 +360,14 @@ ypstat yp_async_lookup_name(xprt, name)
q->ttl = DEF_TTL;
q->sent = 1;
q->xprt = xprt;
q->xid = svcudp_get_xid(xprt);
type = -1; len = sizeof(type);
if (getsockopt(xprt->xp_sock,SOL_SOCKET,SO_TYPE,&type,&len) == -1) {
yp_error("getsockopt failed: %s", strerror(errno));
return(YP_YPERR);
}
q->prot_type = type;
if (q->prot_type == SOCK_DGRAM)
q->xid = svcudp_get_xid(xprt);
q->client_addr = xprt->xp_raddr;
if (!strchr(name, '.'))
q->domain = _res.dnsrch;
@ -383,6 +398,7 @@ ypstat yp_async_lookup_addr(xprt, addr)
register struct circleq_dnsentry *q;
char buf[MAXHOSTNAMELEN];
int a, b, c, d;
int type, len;
if ((q = yp_malloc_dnsent()) == NULL)
return(YP_YPERR);
@ -401,7 +417,14 @@ ypstat yp_async_lookup_addr(xprt, addr)
q->sent = 1;
q->xprt = xprt;
q->domain = NULL;
q->xid = svcudp_get_xid(xprt);
type = -1; len = sizeof(type);
if (getsockopt(xprt->xp_sock,SOL_SOCKET,SO_TYPE,&type,&len) == -1) {
yp_error("getsockopt failed: %s", strerror(errno));
return(YP_YPERR);
}
q->prot_type = type;
if (q->prot_type == SOCK_DGRAM)
q->xid = svcudp_get_xid(xprt);
q->client_addr = xprt->xp_raddr;
q->id = yp_send_dns_query(buf, q->type);