From b009bf6d378704eec392b31f9b6f473daaacb206 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani@krekelä.fi>
Date: Thu, 4 Jul 2019 01:33:20 +0300
Subject: [PATCH] Only read at max 1522 bytes of the 1522 byte buffer

---
 ethertype-dump.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ethertype-dump.c b/ethertype-dump.c
index 402e5a9..3c3280e 100644
--- a/ethertype-dump.c
+++ b/ethertype-dump.c
@@ -104,6 +104,7 @@ int main(int argc, char **argv) {
 		if (frame_length == -1) {
 			err(1, "recv");
 		}
+		size_t frame_data_length = frame_length <= 1522 ? frame_length : 1522;
 
 		if (frame_length < 64) {
 			errno = 0;
@@ -114,7 +115,7 @@ int main(int argc, char **argv) {
 		}
 
 		// Compute the CRC32 of the frame
-		uint32_t crc32_residue = crc32(frame, frame_length);
+		uint32_t crc32_residue = crc32(frame, frame_data_length);
 
 		if (crc32_residue != 0xc704dd7b) {
 			errno = 0;