[src/trunk]: src/usr.sbin/sysinst Make sure we properly truncate snprintf() r...

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

details:   https://anonhg.NetBSD.org/src/rev/601c541f30ec
branches:  trunk
changeset: 448855:601c541f30ec
user:      martin <martin%NetBSD.org@localhost>
date:      Mon Feb 11 19:15:38 2019 +0000

description:
Make sure we properly truncate snprintf() results when the target buffer
is too small, in a way that appeases gcc 7 warnings.

diffstat:

 usr.sbin/sysinst/Makefile.inc |   7 +----
 usr.sbin/sysinst/partman.c    |  53 +++++++++++++++++++++++++++++++-----------
 2 files changed, 40 insertions(+), 20 deletions(-)

diffs (137 lines):

diff -r ef31b8d07eff -r 601c541f30ec usr.sbin/sysinst/Makefile.inc
--- a/usr.sbin/sysinst/Makefile.inc     Mon Feb 11 18:50:15 2019 +0000
+++ b/usr.sbin/sysinst/Makefile.inc     Mon Feb 11 19:15:38 2019 +0000
@@ -1,4 +1,4 @@
-#      $NetBSD: Makefile.inc,v 1.17 2019/02/04 10:22:15 mrg Exp $
+#      $NetBSD: Makefile.inc,v 1.18 2019/02/11 19:15:38 martin Exp $
 #
 # Makefile for sysinst
 
@@ -118,11 +118,6 @@
 COPTS.md.c += -Wno-format-nonliteral
 COPTS.partman.c += -Wno-format-nonliteral -Wno-stack-protector
 
-# Lots of warnings
-.if defined(HAVE_GCC) && ${HAVE_GCC} == 7 && ${ACTIVE_CC} == "gcc"
-COPTS.partman.c+=      -Wno-error=format-truncation
-.endif
-
 # Host to ftp from.  Default:
 #      "ftp.NetBSD.org"
 #
diff -r ef31b8d07eff -r 601c541f30ec usr.sbin/sysinst/partman.c
--- a/usr.sbin/sysinst/partman.c        Mon Feb 11 18:50:15 2019 +0000
+++ b/usr.sbin/sysinst/partman.c        Mon Feb 11 19:15:38 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: partman.c,v 1.25 2018/12/13 12:28:25 martin Exp $ */
+/*     $NetBSD: partman.c,v 1.26 2019/02/11 19:15:38 martin Exp $ */
 
 /*
  * Copyright 2012 Eugene Lozovoy
@@ -1893,7 +1893,7 @@
 int
 pm_getrefdev(pm_devs_t *pm_cur)
 {
-       int i, ii, dev_num, num_devs, num_devs_s;
+       int i, ii, dev_num, num_devs, num_devs_s, r;
        char dev[SSTRSIZE]; dev[0] = '\0';
 
        pm_cur->refdev = NULL;
@@ -1902,10 +1902,15 @@
                for (i = 0; i < MAX_CGD; i++)
                        if (cgds[i].blocked && cgds[i].node == dev_num) {
                                pm_cur->refdev = &cgds[i];
-
-                               snprintf(pm_cur->diskdev_descr, STRSIZE, "%s (%s, %s-%d)",
-                                       pm_cur->diskdev_descr, cgds[i].pm_name,
-                                       cgds[i].enc_type, cgds[i].key_size);
+                               r = snprintf(pm_cur->diskdev_descr,
+                                   sizeof(pm_cur->diskdev_descr)-1,
+                                   "%s (%s, %s-%d)",
+                                   pm_cur->diskdev_descr, cgds[i].pm_name,
+                                   cgds[i].enc_type, cgds[i].key_size);
+                               if (r >= (int)sizeof(pm_cur->diskdev_descr))
+                                       pm_cur->diskdev_descr[
+                                           sizeof(pm_cur->diskdev_descr)-1]
+                                           = 0;
                                break;
                        }
        } else if (! strncmp(pm_cur->diskdev, "vnd", 3)) {
@@ -1914,8 +1919,17 @@
                        if (vnds[i].blocked && vnds[i].node == dev_num) {
                                pm_cur->refdev = &vnds[i];
                                pm_getdevstring(dev, SSTRSIZE, vnds[i].pm, vnds[i].pm_part);
-                               snprintf(pm_cur->diskdev_descr, STRSIZE, "%s (%s, %s)",
-                                       pm_cur->diskdev_descr, dev, vnds[i].filepath);
+                               r = snprintf(pm_cur->diskdev_descr,
+                                   sizeof(pm_cur->diskdev_descr)-1,
+                                   "%s (%s, %s)",
+                                   pm_cur->diskdev_descr, dev,
+                                   vnds[i].filepath);
+                               if (r >= (int)sizeof(pm_cur->diskdev_descr))
+                                       pm_cur->diskdev_descr[
+                                           sizeof(pm_cur->diskdev_descr)-1]
+                                           = 0;
+                               pm_cur->diskdev_descr[
+                                   sizeof(pm_cur->diskdev_descr)-1] = 0;
                                break;
                        }
        } else if (! strncmp(pm_cur->diskdev, "raid", 4)) {
@@ -1931,9 +1945,14 @@
                                                else
                                                        num_devs++;
                                        }
-                               snprintf(pm_cur->diskdev_descr, STRSIZE,
+                               r = snprintf(pm_cur->diskdev_descr,
+                                       sizeof(pm_cur->diskdev_descr)-1,
                                        "%s (lvl %d, %d disks, %d spare)", pm_cur->diskdev_descr,
                                        raids[i].raid_level, num_devs, num_devs_s);
+                               if (r >= (int)sizeof(pm_cur->diskdev_descr))
+                                       pm_cur->diskdev_descr[
+                                           sizeof(pm_cur->diskdev_descr)-1]
+                                           = 0;
                                break;
                        }
        } else
@@ -2178,13 +2197,16 @@
 static int
 pm_mount(pm_devs_t *pm_cur, int part_num)
 {
-       int error = 0;
+       int error = 0, r;
        char buf[MOUNTLEN];
 
        if (strlen(pm_cur->bsdlabel[part_num].mounted) > 0)
                return 0;
 
-       snprintf(buf, MOUNTLEN, "/tmp/%s%c", pm_cur->diskdev, part_num + 'a');
+       r = snprintf(buf, sizeof(buf)-1, "/tmp/%s%c", pm_cur->diskdev,
+           part_num + 'a');
+       if (r >= (int)sizeof(buf))
+               buf[sizeof(buf)-1] = 0;
        if (! dir_exists_p(buf))
                run_program(RUN_DISPLAY | RUN_PROGRESS, "/bin/mkdir -p %s", buf);
        if (pm_cur->bsdlabel[part_num].pi_flags & PIF_MOUNT &&
@@ -2479,7 +2501,7 @@
 {
        const char *dev_status = "";
        char buf[STRSIZE];
-       int part_num = ((part_entry_t *)arg)[opt].dev_num;
+       int r, part_num = ((part_entry_t *)arg)[opt].dev_num;
        pm_devs_t *pm_cur = ((part_entry_t *)arg)[opt].dev_ptr;
 
        switch (((part_entry_t *)arg)[opt].type) {
@@ -2531,8 +2553,11 @@
                                pm_cur->bsdlabel[part_num].pi_size / (MEG / pm_cur->sectorsize));
                        break;
                case PM_SPEC_T:
-                       snprintf(buf, STRSIZE, "%s: %s",
-                               pm_cur->diskdev_descr, pm_cur->bsdlabel[0].pi_mount);
+                       r = snprintf(buf, sizeof(buf)-1, "%s: %s",
+                           pm_cur->diskdev_descr,
+                           pm_cur->bsdlabel[0].pi_mount);
+                       if (r >= (int)sizeof(buf))
+                               buf[sizeof(buf)-1] = 0;
                        wprintw(m->mw, "%-33.32s %-22.21s %11luM", buf,
                                getfslabelname(pm_cur->bsdlabel[0].pi_fstype),
                                pm_cur->bsdlabel[0].pi_size / (MEG / pm_cur->sectorsize));