From: Tobias Stoeckmann <tobias@stoeckmann.org>
Date: Thu, 25 Jun 2026 18:58:13 +0000 (+0200)
Subject: 7zip: Simplify decode_encoded_header_info
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cd938e2815b2cbbbbd0d4918cd737b62aa31605e;p=thirdparty%2Flibarchive.git

7zip: Simplify decode_encoded_header_info

With correct data types in place, simplify the overflow check by using
checked arithmetic and simple comparison.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
---

diff --git a/libarchive/archive_read_support_format_7zip.c b/libarchive/archive_read_support_format_7zip.c
index 0d4da2a7b..df332d076 100644
--- a/libarchive/archive_read_support_format_7zip.c
+++ b/libarchive/archive_read_support_format_7zip.c
@@ -3200,6 +3200,7 @@ static int
 decode_encoded_header_info(struct archive_read *a, struct _7z_stream_info *si)
 {
 	struct _7zip *zip = (struct _7zip *)a->format->data;
+	int64_t pi_end;
 
 	errno = 0;
 	if (read_StreamsInfo(a, si) < 0) {
@@ -3217,9 +3218,12 @@ decode_encoded_header_info(struct archive_read *a, struct _7z_stream_info *si)
 		return (ARCHIVE_FATAL);
 	}
 
-	if (zip->header_offset < si->pi.pos + si->pi.sizes[0] ||
-	    si->pi.pos + si->pi.sizes[0] < 0 ||
-	    si->pi.sizes[0] == 0 || si->pi.pos < 0) {
+	if (archive_ckd_add_i64(&pi_end, si->pi.pos, si->pi.sizes[0])) {
+		archive_set_error(&a->archive, -1, "Malformed 7-Zip archive");
+		return (ARCHIVE_FATAL);
+	}
+
+	if (zip->header_offset < pi_end) {
 		archive_set_error(&a->archive, -1, "Malformed Header offset");
 		return (ARCHIVE_FATAL);
 	}