From: Francois-Xavier Le Bail <devel.fx.lebail@orange.fr>
Date: Thu, 6 May 2021 11:39:10 +0000 (+0200)
Subject: Ethernet: Add a bounds check
X-Git-Tag: tcpdump-4.99.1~30
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/78f618d2c110489f95354198d4e9054214b1b880

Ethernet: Add a bounds check

Avoid to have p (current pointer on packet data) > ndo->ndo_snapend
in isoclns_print() in some cases.

Moreover:
Add a "FIXME" comment.

(cherry picked from commit 7b7b84716e604abd8bd92cee75e6385cab6ce3dc)
---

diff --git a/print-ether.c b/print-ether.c
index 2596cd6d..da95862b 100644
--- a/print-ether.c
+++ b/print-ether.c
@@ -564,6 +564,9 @@ ethertype_print(netdissect_options *ndo,
 			nd_print_trunc(ndo);
 			return (1);
 		}
+		/* At least one byte is required */
+		/* FIXME: Reference for this byte? */
+		ND_TCHECK_LEN(p, 1);
 		isoclns_print(ndo, p + 1, length - 1);
 		return(1);