disklabel missing return value checks on asprintf

[Nathaniel Houghton]

>Synopsis:      disklabel missing return value checks on asprintf
>Category:      system
>Environment:
        System      : OpenBSD 5.5
        Details     : OpenBSD 5.5-stable (GENERIC.MP) #0: Sun May 11 00:29:07 
PDT 2014
                         
r...@iron.brainwerk.org:/usr/src/sys/arch/amd64/compile/GENERIC.MP

        Architecture: OpenBSD.amd64
        Machine     : amd64
>Description:
        The disklabel.c file calls asprintf in a few places without checking 
the return value
>How-To-Repeat:
        N/A
>Fix:

Patch against 5.5-stable.

Index: disklabel.c
===================================================================
RCS file: /cvs/src/sbin/disklabel/disklabel.c,v
retrieving revision 1.192
diff -u -p -r1.192 disklabel.c
--- disklabel.c 14 Feb 2014 15:03:43 -0000      1.192
+++ disklabel.c 19 May 2014 03:21:40 -0000
@@ -457,11 +457,13 @@ readlabel(int f)
                        err(4, "ioctl DIOCGDINFO");
        }
 
-       asprintf(&partname, "/dev/%s%c", dkname, 'a');
-       asprintf(&partduid,
+       if (asprintf(&partname, "/dev/%s%c", dkname, 'a') == -1)
+               err(4, "asprintf");
+       if (asprintf(&partduid,
            "%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx.a",
             lab.d_uid[0], lab.d_uid[1], lab.d_uid[2], lab.d_uid[3],
-            lab.d_uid[4], lab.d_uid[5], lab.d_uid[6], lab.d_uid[7]);
+            lab.d_uid[4], lab.d_uid[5], lab.d_uid[6], lab.d_uid[7]) == -1)
+               err(4, "asprintf");
        setfsent();
        for (i = 0; i < MAXPARTITIONS; i++) {
                partname[strlen(dkname) + 5] = 'a' + i;