misc/172576: librpc segfaults when out of memory

[Ritesh Shah]

>Number:         172576
>Category:       misc
>Synopsis:       librpc segfaults when out of memory
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Oct 10 22:58:22 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Ritesh Shah
>Release:        7.2, 8.1, 9.0
>Organization:
>Environment:
7.2-RELEASE-p4 FreeBSD 7.2-RELEASE-p4 #0: Fri Oct  2 08:22:32 UTC 2009     root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
xdrrec_create() routine in lib/libc/xdr/xdr_rec.c returns a void. Under low memory condition this routine can bail out early and leave part of the XDR structrure uninitialized. 

The callers : 

clnt_vc_create() in lib/libc/rpc/clnt_vc.c & 
makefd_xprt() in lib/libc/rpc/svc_vc.c

do not check whether failed or not. 

This can lead to segfault when uninitialized pointers are accessed.

This bug exists in FreeBSD 9 as well.

192	        rstrm->in_base = mem_alloc(recvsize);
193	        if (rstrm->in_base == NULL) {
194	                warnx("xdrrec_create: out of memory");
195	                mem_free(rstrm->out_base, sendsize);
196	                mem_free(rstrm, sizeof(RECSTREAM));
197	                return;
198	        }
199	        /*
200	         * now the rest ...
201	         */
202	        xdrs->x_ops = &xdrrec_ops;
203	        xdrs->x_private = rstrm;
204	        rstrm->tcp_handle = tcp_handle;



>How-To-Repeat:

>Fix:
It has been reported against netbsd as well.

http://mail-index.netbsd.org/netbsd-bugs/2012/08/06/msg029375.html

I can provide a patch if there is an agreement on how it should be fixed.

>Release-Note:
>Audit-Trail:
>Unformatted: