From e0c4ebfe122f8bc75cefeb881524db168ef6eb0b Mon Sep 17 00:00:00 2001
From: krzysztof-cabaj <kcabaj@gmail.com>
Date: Sat, 16 Sep 2023 12:20:21 -0400
Subject: [PATCH] sys/shell/ping: add protection from icmp packet overflow

---
 sys/shell/cmds/gnrc_icmpv6_echo.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/sys/shell/cmds/gnrc_icmpv6_echo.c b/sys/shell/cmds/gnrc_icmpv6_echo.c
index 3c1c3776f68a1..784f8f4705343 100644
--- a/sys/shell/cmds/gnrc_icmpv6_echo.c
+++ b/sys/shell/cmds/gnrc_icmpv6_echo.c
@@ -172,6 +172,7 @@ static int _configure(int argc, char **argv, _ping_data_t *data)
 {
     char *cmdname = argv[0];
     int res = 1;
+    int value;
 
     /* parse command line arguments */
     for (int i = 1; i < argc; i++) {
@@ -207,7 +208,13 @@ static int _configure(int argc, char **argv, _ping_data_t *data)
                     /* intentionally falls through */
                 case 's':
                     if ((++i) < argc) {
-                        data->datalen = atoi(argv[i]);
+                        value = atoi(argv[i]);
+
+                        if(value < 0 || value > 65527) {
+                            printf("ICMPv6 datagram size should be in range <0, 65527>.\n");
+                            return -1;
+                        }
+                        data->datalen = value;
                         continue;
                     }
                     /* intentionally falls through */