Date: 30 May 2001 05:31:01 -0400 From: Sudish Joseph <sudish@mindspring.com> To: FreeBSD-gnats-submit@freebsd.org Subject: alpha/27766: /usr/bin/ppp issues unaligned accesses and core dumps on an alpha Message-ID: <yviar8x7xjxm.fsf@ra.eng.mindspring.net>
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>Number: 27766
>Category: alpha
>Synopsis: /usr/bin/ppp issues unaligned accesses and core dumps on alpha (patch included)
>Confidential: no
>Severity: critical
>Priority: medium
>Responsible: freebsd-alpha
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Wed May 30 02:40:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator: Sudish Joseph
>Release: FreeBSD 4.3-STABLE alpha
>Organization:
>Environment:
System: FreeBSD aleph.weenal.com 4.3-STABLE FreeBSD 4.3-STABLE #0: Wed May 30 02:26:09 GMT 2001 root@aleph.weenal.com:/usr/obj/usr/src/sys/SUDISH alpha
>Description:
/usr/sbin/ppp attempts unaligned accesses when resolving dns queries.
On an alpha this can and does cause a core dump. The patch below removes
the unaligned access.
>How-To-Repeat:
Run /usr/bin/ppp on an alpha and do anything that causes ppp to do dns
lookups. For instance, try a traceroute without -n. Given the right
dns reply packet -- one with unaligned data -- ppp dumps core.
>Fix:
The following patch replaces the unaligned access with a bcopy(), which
fixes the problem.
--- /usr/src/usr.sbin/ppp/ip.c Thu May 17 19:11:47 2001
+++ /usr/src/usr.sbin/ppp/ip.c Tue May 29 06:10:34 2001
@@ -452,6 +452,7 @@
const u_char *ptr;
u_short *hptr;
int len;
+ u_short tmp;
ptr = (const char *)uh + sizeof *uh;
len = ntohs(uh->uh_ulen) - sizeof *uh;
@@ -489,8 +490,10 @@
n += len;
}
*n = '\0';
- qtype = dns_Qtype2Txt(ntohs(*(const u_short *)end));
- qclass = dns_Qclass2Txt(ntohs(*(const u_short *)(end + 2)));
+ bcopy(end, &tmp, sizeof(tmp));
+ qtype = dns_Qtype2Txt(ntohs(tmp));
+ bcopy(end + 2, &tmp, sizeof(tmp));
+ qclass = dns_Qclass2Txt(ntohs(tmp));
log_Printf(LogDNS, "%sbound query %s %s %s\n",
direction, qclass, qtype, namewithdot);
>Release-Note:
>Audit-Trail:
>Unformatted:
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