svn commit: r368778 - head/usr.bin/login

[Pedro F. Giffuni]

Author: pfg
Date: Sat Dec 19 03:07:38 2020
New Revision: 368778
URL: https://svnweb.freebsd.org/changeset/base/368778

Log:
  login(1): when exporting variables check the result of setenv(3)
  
  When exporting a variable we correctly check all the preconditions that
  could make setenv(3) fail. Checking the setenv(3) return value seems
  redundant, but given that login(1) is critical, it doesn't hurt to have
  a post-check.
  
  This change is based on the "Principles of Secure Coding" course by
  Matthew Bishop, PhD., which specifically discusses this code in FreeBSD.
  
  (This change redoes r368776 due to a silly mistake)

Modified:
  head/usr.bin/login/login.c

Modified: head/usr.bin/login/login.c
==============================================================================
--- head/usr.bin/login/login.c	Sat Dec 19 02:42:14 2020	(r368777)
+++ head/usr.bin/login/login.c	Sat Dec 19 03:07:38 2020	(r368778)
@@ -793,6 +793,7 @@ export(const char *s)
 	char *p;
 	const char **pp;
 	size_t n;
+	int rv;
 
 	if (strlen(s) > 1024 || (p = strchr(s, '=')) == NULL)
 		return (0);
@@ -804,8 +805,10 @@ export(const char *s)
 			return (0);
 	}
 	*p = '\0';
-	(void)setenv(s, p + 1, 1);
+	rv = setenv(s, p + 1, 1);
 	*p = '=';
+	if (rv == -1)
+		return (0);
 	return (1);
 }