bin/172289: Check return value of setuid()

[Erik Cederstrand]

>Number:         172289
>Category:       bin
>Synopsis:       Check return value of setuid()
>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:   Tue Oct 02 21:30:10 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Erik Cederstrand
>Release:        CURRENT
>Organization:
>Environment:
>Description:
When dropping root privileges, ping doesn't check the return value of setuid(). If setuid() fails, which it can do for a number of reasons, root privileges are not dropped. This is a privilege escalation.
>How-To-Repeat:

>Fix:
Check return value of setuid and abort if it fails.

Patch attached with submission follows:

Index: ping.c
===================================================================
--- ping.c	(revision 240960)
+++ ping.c	(working copy)
@@ -255,7 +255,8 @@
 	s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
 	sockerrno = errno;
 
-	setuid(getuid());
+	if (setuid(getuid()) != 0)
+        err(EX_NOPERM, "setuid() failed");
 	uid = getuid();
 
 	alarmtimeout = df = preload = tos = 0;


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