[src/trunk]: src/usr.bin/last PR/23409: Geoff C. Wing: make sure we only prin...

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

details:   https://anonhg.NetBSD.org/src/rev/21bdd6e31965
branches:  trunk
changeset: 574562:21bdd6e31965
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Mar 04 17:11:19 2005 +0000

description:
PR/23409: Geoff C. Wing: make sure we only print nul terminated strings.

diffstat:

 usr.bin/last/want.c |  60 ++++++++++++++++++++++++++++++++--------------------
 1 files changed, 37 insertions(+), 23 deletions(-)

diffs (142 lines):

diff -r 9f2a16ba6a68 -r 21bdd6e31965 usr.bin/last/want.c
--- a/usr.bin/last/want.c       Fri Mar 04 16:46:28 2005 +0000
+++ b/usr.bin/last/want.c       Fri Mar 04 17:11:19 2005 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: want.c,v 1.4 2004/11/19 21:41:25 christos Exp $        */
+/*     $NetBSD: want.c,v 1.5 2005/03/04 17:11:19 christos Exp $        */
 
 /*
  * Copyright (c) 1987, 1993, 1994
@@ -32,13 +32,14 @@
 
 static void onintr(int);
 static int want(struct utmp *, int);
-static const char *gethost(struct utmp *, int);
+static const char *gethost(struct utmp *, const char *, int);
 
 static const char *
-gethost(struct utmp* ut, int numeric)
+/*ARGSUSED*/
+gethost(struct utmp *ut, const char *host, int numeric)
 {
 #if FIRSTVALID == 0
-       return numeric ? "" : ut->ut_host;
+       return numeric ? "" : host;
 #else
        if (numeric) {
                static char buf[512];
@@ -47,10 +48,17 @@
                    (struct sockaddr *)&ut->ut_ss);
                return buf;
        } else
-               return ut->ut_host;
+               return host;
 #endif
 }
 
+#define NULTERM(what) \
+       if (check ## what) \
+               (void)strlcpy(what ## p = what ## buf, bp->ut_ ## what, \
+                   sizeof(what ## buf)); \
+       else \
+               what ## p = bp->ut_ ## what
+       
 /*
  * wtmp --
  *     read through the wtmp file
@@ -66,6 +74,12 @@
        int     bytes, wfd;
        char    *ct, *crmsg;
        size_t  len = sizeof(*buf) * MAXUTMP;
+       char namebuf[sizeof(bp->ut_name) + 1], *namep;
+       char linebuf[sizeof(bp->ut_line) + 1], *linep;
+       char hostbuf[sizeof(bp->ut_host) + 1], *hostp;
+       int checkname = namesz > sizeof(bp->ut_name);
+       int checkline = linesz > sizeof(bp->ut_line);
+       int checkhost = hostsz > sizeof(bp->ut_host);
 
        if ((buf = malloc(len)) == NULL)
                err(1, "Cannot allocate utmp buffer");
@@ -85,24 +99,27 @@
                    (bytes = read(wfd, buf, len)) == -1)
                        err(1, "%s", file);
                for (bp = &buf[bytes / sizeof(*buf) - 1]; bp >= buf; --bp) {
+                       NULTERM(name);
+                       NULTERM(line);
+                       NULTERM(host);
                        /*
                         * if the terminal line is '~', the machine stopped.
                         * see utmp(5) for more info.
                         */
-                       if (bp->ut_line[0] == '~' && !bp->ut_line[1]) {
+                       if (linep[0] == '~' && !linep[1]) {
                                /* everybody just logged out */
                                for (T = ttylist; T; T = T->next)
                                        T->logout = -bp->ut_timefld;
                                currentout = -bp->ut_timefld;
-                               crmsg = strncmp(bp->ut_name, "shutdown",
+                               crmsg = strncmp(namep, "shutdown",
                                    namesz) ? "crash" : "shutdown";
                                if (want(bp, NO)) {
                                        ct = fmttime(bp->ut_timefld, fulltime);
                                        printf("%-*.*s  %-*.*s %-*.*s %s\n",
-                                           namesz, namesz, bp->ut_name,
-                                           linesz, linesz, bp->ut_line,
+                                           namesz, namesz, namep,
+                                           linesz, linesz, linep,
                                            hostsz, hostsz,
-                                           gethost(bp, numeric), ct);
+                                           gethost(bp, hostp, numeric), ct);
                                        if (maxrec != -1 && !--maxrec)
                                                return;
                                }
@@ -112,17 +129,14 @@
                         * if the line is '{' or '|', date got set; see
                         * utmp(5) for more info.
                         */
-                       if ((bp->ut_line[0] == '{' || bp->ut_line[0] == '|')
-                           && !bp->ut_line[1]) {
+                       if ((linep[0] == '{' || linep[0] == '|') && !linep[1]) {
                                if (want(bp, NO)) {
                                        ct = fmttime(bp->ut_timefld, fulltime);
                                printf("%-*.*s  %-*.*s %-*.*s %s\n",
-                                   namesz, namesz,
-                                   bp->ut_name,
-                                   linesz, linesz,
-                                   bp->ut_line,
+                                   namesz, namesz, namep,
+                                   linesz, linesz, linep,
                                    hostsz, hostsz,
-                                   gethost(bp, numeric),
+                                   gethost(bp, hostp, numeric),
                                    ct);
                                        if (maxrec && !--maxrec)
                                                return;
@@ -133,21 +147,21 @@
                        for (T = ttylist;; T = T->next) {
                                if (!T) {
                                        /* add new one */
-                                       T = addtty(bp->ut_line);
+                                       T = addtty(linep);
                                        break;
                                }
-                               if (!strncmp(T->tty, bp->ut_line, LINESIZE))
+                               if (!strncmp(T->tty, linep, LINESIZE))
                                        break;
                        }
                        if (TYPE(bp) == SIGNATURE)
                                continue;
-                       if (bp->ut_name[0] && want(bp, YES)) {
+                       if (namep[0] && want(bp, YES)) {
                                ct = fmttime(bp->ut_timefld, fulltime);
                                printf("%-*.*s  %-*.*s %-*.*s %s ",
-                                   namesz, namesz, bp->ut_name,
-                                   linesz, linesz, bp->ut_line,
+                                   namesz, namesz, namep,
+                                   linesz, linesz, linep,
                                    hostsz, hostsz,
-                                   gethost(bp, numeric),
+                                   gethost(bp, hostp, numeric),
                                    ct);
                                if (!T->logout)
                                        puts("  still logged in");