[src/trunk]: src/sbin/ping PR bin/36997 Zafer Aydogan: ping doesn't validate ...

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

details:   https://anonhg.NetBSD.org/src/rev/b5c53145e6aa
branches:  trunk
changeset: 819801:b5c53145e6aa
user:      dholland <dholland%NetBSD.org@localhost>
date:      Sun Dec 18 00:21:33 2016 +0000

description:
PR bin/36997 Zafer Aydogan: ping doesn't validate numeric inputs enough.

Check for values between INT_MAX and LONG_MAX (if they're different)
when using strtol to get an int. This applies to the -c and -l options;
the other uses were already checked.

Also limit the inter-packet interval given with -i to values that
don't cause integer overflow calling poll() with milliseconds.

Really large intervals (the number is read as floating point) can
produce positive poll() values but negative integers when converted to
struct timespec; this produces behavior akin to using -l at first and
could be construed as a local DoS vulnerability.

diffstat:

 sbin/ping/ping.c |  33 +++++++++++++++++++++++++++------
 1 files changed, 27 insertions(+), 6 deletions(-)

diffs (68 lines):

diff -r 0d8ec0546b77 -r b5c53145e6aa sbin/ping/ping.c
--- a/sbin/ping/ping.c  Sat Dec 17 18:41:13 2016 +0000
+++ b/sbin/ping/ping.c  Sun Dec 18 00:21:33 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ping.c,v 1.112 2016/10/07 22:31:05 joerg Exp $ */
+/*     $NetBSD: ping.c,v 1.113 2016/12/18 00:21:33 dholland Exp $      */
 
 /*
  * Copyright (c) 1989, 1993
@@ -58,7 +58,7 @@
 
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: ping.c,v 1.112 2016/10/07 22:31:05 joerg Exp $");
+__RCSID("$NetBSD: ping.c,v 1.113 2016/12/18 00:21:33 dholland Exp $");
 #endif
 
 #include <stdio.h>
@@ -295,11 +295,17 @@
                        compat = 1;
                        break;
                case 'c':
-                       npackets = strtol(optarg, &p, 0);
-                       if (*p != '\0' || npackets <= 0)
+                       l = strtol(optarg, &p, 0);
+                       if (*p != '\0' || l <= 0)
                                errx(EXIT_FAILURE,
                                    "Bad/invalid number of packets: %s",
                                    optarg);
+#if INT_MAX < LONG_MAX
+                       if (l > INT_MAX)
+                               errx(EXIT_FAILURE,
+                                   "Too many packets to count: %ld", l);
+#endif
+                       npackets = l;
                        break;
                case 'D':
                        pingflags |= F_DF;
@@ -318,12 +324,27 @@
                        if (*p != '\0' || interval <= 0)
                                errx(EXIT_FAILURE, "Bad/invalid interval: %s",
                                    optarg);
+                       /*
+                        * In order to avoid overflowing the microseconds
+                        * argument of poll() the interval must be less than
+                        * INT_MAX/1000. Limit it to one second less than
+                        * that to be safe.
+                        */
+                       if (interval >= INT_MAX/1000.0 - 1.0)
+                               errx(EXIT_FAILURE,
+                                   "Timing interval %g too large", interval);
                        break;
                case 'l':
-                       preload = strtol(optarg, &p, 0);
-                       if (*p != '\0' || preload < 0)
+                       l = strtol(optarg, &p, 0);
+                       if (*p != '\0' || l < 0)
                                errx(EXIT_FAILURE, "Bad/invalid preload value: "
                                    "%s", optarg);
+#if INT_MAX < LONG_MAX
+                       if (l > INT_MAX)
+                               errx(EXIT_FAILURE,
+                                   "Too many preload packets: %ld", l);
+#endif
+                       preload = l;
                        break;
                case 'n':
                        pingflags |= F_NUMERIC;