[src/trunk]: src/usr.sbin/lastlogin Use memcpy for copying out lastlog and la...

[kim <kim%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/307ddc668b5d
branches:  trunk
changeset: 971856:307ddc668b5d
user:      kim <kim%NetBSD.org@localhost>
date:      Wed May 06 19:31:32 2020 +0000

description:
Use memcpy for copying out lastlog and lastlogx text

Lastlog and lastlogx text fields are not NUL-terminated when original data
is truncated.

diffstat:

 usr.sbin/lastlogin/lastlogin.c |  18 ++++++++++++------
 1 files changed, 12 insertions(+), 6 deletions(-)

diffs (65 lines):

diff -r 1355b5322a60 -r 307ddc668b5d usr.sbin/lastlogin/lastlogin.c
--- a/usr.sbin/lastlogin/lastlogin.c    Wed May 06 18:49:26 2020 +0000
+++ b/usr.sbin/lastlogin/lastlogin.c    Wed May 06 19:31:32 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: lastlogin.c,v 1.17 2020/05/06 13:47:39 kim Exp $       */
+/*     $NetBSD: lastlogin.c,v 1.18 2020/05/06 19:31:32 kim Exp $       */
 /*
  * Copyright (c) 1996 John M. Vinopal
  * All rights reserved.
@@ -33,7 +33,7 @@
 
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: lastlogin.c,v 1.17 2020/05/06 13:47:39 kim Exp $");
+__RCSID("$NetBSD: lastlogin.c,v 1.18 2020/05/06 19:31:32 kim Exp $");
 #endif
 
 #include <sys/types.h>
@@ -77,6 +77,10 @@
 # define UTX_HOSTSIZE  256
 #endif
 
+/*
+ * Fields in the structure below are 1 byte longer than the maximum possible
+ * for NUL-termination.
+ */
 struct output {
        struct timeval   o_tv;
        char             o_name[UTX_USERSIZE+1];
@@ -268,12 +272,13 @@
 {
        struct output   o;
 
+       memset(&o, 0, sizeof(o));
        if (numeric > 1)
                (void)snprintf(o.o_name, sizeof(o.o_name), "%d", p->pw_uid);
        else
                (void)strlcpy(o.o_name, p->pw_name, sizeof(o.o_name));
-       (void)strlcpy(o.o_line, l->ll_line, sizeof(l->ll_line));
-       (void)strlcpy(o.o_host, l->ll_host, sizeof(l->ll_host));
+       (void)memcpy(o.o_line, l->ll_line, sizeof(l->ll_line));
+       (void)memcpy(o.o_host, l->ll_host, sizeof(l->ll_host));
        o.o_tv.tv_sec = l->ll_time;
        o.o_tv.tv_usec = 0;
        o.next = NULL;
@@ -392,16 +397,17 @@
 {
        struct output   o;
 
+       memset(&o, 0, sizeof(o));
        if (numeric > 1)
                (void)snprintf(o.o_name, sizeof(o.o_name), "%d", p->pw_uid);
        else
                (void)strlcpy(o.o_name, p->pw_name, sizeof(o.o_name));
-       (void)strlcpy(o.o_line, l->ll_line, sizeof(l->ll_line));
+       (void)memcpy(o.o_line, l->ll_line, sizeof(l->ll_line));
        if (numeric)
                (void)sockaddr_snprintf(o.o_host, sizeof(o.o_host), "%a",
                    (struct sockaddr *)&l->ll_ss);
        else
-               (void)strlcpy(o.o_host, l->ll_host, sizeof(l->ll_host));
+               (void)memcpy(o.o_host, l->ll_host, sizeof(l->ll_host));
        o.o_tv = l->ll_tv;
        o.next = NULL;