From 019c4302ad86fd6981e8abc90cd8cb58003b662c Mon Sep 17 00:00:00 2001
From: Přemysl Eric Janouch <p@janouch.name>
Date: Sun, 8 Dec 2024 22:36:02 +0100
Subject: Handle tiny files gracefully

Lua detection functions used to cause fatal errors on failure to read.

We could also reconsider treating detection errors as fatal.
---
 plugins/pcap.lua | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'plugins/pcap.lua')

diff --git a/plugins/pcap.lua b/plugins/pcap.lua
index a02fc8f..7ad6606 100644
--- a/plugins/pcap.lua
+++ b/plugins/pcap.lua
@@ -16,11 +16,17 @@
 --
 
 local detect = function (c)
+	if #c < 4 then
+		return false
+	end
 	local magic = c:u32 ()
 	return magic == 0xa1b2c3d4 or magic == 0xd4c3b2a1
 end
 
 local detect_ng = function (c)
+	if #c < 8 then
+		return false
+	end
 	local magic = c (9):u32 ()
 	return c:u32 () == 0x0a0d0d0a
 		and (magic == 0x1a2b3c4d or magic == 0x4d3c2b1a)
-- 
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