From c69c5c62775d84aa56a43bedaa4fcacbb73d403d Mon Sep 17 00:00:00 2001
From: Damien Neil <[email protected]>
Date: Tue, 14 May 2024 14:39:10 -0700
Subject: [PATCH] [Backport] archive/zip: treat truncated EOCDR comment as an
 error

CVE: CVE-2024-24789
Reference: https://go-review.googlesource.com/c/go/+/588796

When scanning for an end of central directory record,
treat an EOCDR signature with a record containing a truncated
comment as an error. Previously, we would skip over the invalid
record and look for another one. Other implementations do not
do this (they either consider this a hard error, or just ignore
the truncated comment). This parser misalignment allowed
presenting entirely different archive contents to Go programs
and other zip decoders.

For #66869
Fixes #67554
Fixes CVE-2024-24789

Change-Id: I94e5cb028534bb5704588b8af27f1e22ea49c7c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/585397
Reviewed-by: Joseph Tsai <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
(cherry picked from commit 33d725e5758bf1fea62e6c77fc70b57a828a49f5)
Reviewed-on: https://go-review.googlesource.com/c/go/+/588796
Reviewed-by: Matthew Dempsky <[email protected]>
Signed-off-by: Ma Chang Wang [email protected]
---
 src/archive/zip/reader.go | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/archive/zip/reader.go b/src/archive/zip/reader.go
index 1fde1decc4..20356bde0e 100644
--- a/src/archive/zip/reader.go
+++ b/src/archive/zip/reader.go
@@ -699,9 +699,13 @@ func findSignatureInBlock(b []byte) int {
 		if b[i] == 'P' && b[i+1] == 'K' && b[i+2] == 0x05 && b[i+3] == 0x06 {
 			// n is length of comment
 			n := int(b[i+directoryEndLen-2]) | int(b[i+directoryEndLen-1])<<8
-			if n+directoryEndLen+i <= len(b) {
-				return i
+			if n+directoryEndLen+i > len(b) {
+				// Truncated comment.
+				// Some parsers (such as Info-ZIP) ignore the truncated comment
+				// rather than treating it as a hard error.
+				return -1
 			}
+			return i
 		}
 	}
 	return -1
-- 
2.33.0