From: Tobias Stoeckmann <tobias@stoeckmann.org>
Date: Tue, 19 May 2026 19:16:24 +0000 (+0200)
Subject: tar: Fix empty wide character string handling
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=843b3baea18d20cace458c4a3d1bbf2fa6f45018;p=thirdparty%2Flibarchive.git

tar: Fix empty wide character string handling

Apply the same fix as done in commit
c246ec5d058a3f70a2d3fb765f92fe9db77b25df for non-wide character
strings.

Without this, empty strings lead to out of boundary read accesses.

Resolves #3046.

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

diff --git a/libarchive/archive_write_set_format_gnutar.c b/libarchive/archive_write_set_format_gnutar.c
index b67007a63..f2ba4a0db 100644
--- a/libarchive/archive_write_set_format_gnutar.c
+++ b/libarchive/archive_write_set_format_gnutar.c
@@ -321,7 +321,8 @@ archive_write_gnutar_header(struct archive_write *a,
 		const wchar_t *wp;
 
 		wp = archive_entry_pathname_w(entry);
-		if (wp != NULL && wp[wcslen(wp) -1] != L'/') {
+		if (wp != NULL && wp[0] != L'\0' &&
+		    wp[wcslen(wp) - 1] != L'/') {
 			struct archive_wstring ws;
 
 			archive_string_init(&ws);
diff --git a/libarchive/archive_write_set_format_pax.c b/libarchive/archive_write_set_format_pax.c
index f3589d685..debd2c6bf 100644
--- a/libarchive/archive_write_set_format_pax.c
+++ b/libarchive/archive_write_set_format_pax.c
@@ -676,7 +676,8 @@ archive_write_pax_header(struct archive_write *a,
 			const wchar_t *wp;
 
 			wp = archive_entry_pathname_w(entry_original);
-			if (wp != NULL && wp[wcslen(wp) -1] != L'/') {
+			if (wp != NULL && wp[0] != L'\0' &&
+			    wp[wcslen(wp) - 1] != L'/') {
 				struct archive_wstring ws;
 
 				archive_string_init(&ws);
diff --git a/libarchive/archive_write_set_format_ustar.c b/libarchive/archive_write_set_format_ustar.c
index 97724c158..e84152ea1 100644
--- a/libarchive/archive_write_set_format_ustar.c
+++ b/libarchive/archive_write_set_format_ustar.c
@@ -281,7 +281,8 @@ archive_write_ustar_header(struct archive_write *a, struct archive_entry *entry)
 		const wchar_t *wp;
 
 		wp = archive_entry_pathname_w(entry);
-		if (wp != NULL && wp[wcslen(wp) -1] != L'/') {
+		if (wp != NULL && wp[0] != L'\0' &&
+		    wp[wcslen(wp) - 1] != L'/') {
 			struct archive_wstring ws;
 
 			archive_string_init(&ws);
diff --git a/libarchive/archive_write_set_format_v7tar.c b/libarchive/archive_write_set_format_v7tar.c
index 37ba73a13..91c5e8e42 100644
--- a/libarchive/archive_write_set_format_v7tar.c
+++ b/libarchive/archive_write_set_format_v7tar.c
@@ -259,7 +259,8 @@ archive_write_v7tar_header(struct archive_write *a, struct archive_entry *entry)
 		const wchar_t *wp;
 
 		wp = archive_entry_pathname_w(entry);
-		if (wp != NULL && wp[wcslen(wp) -1] != L'/') {
+		if (wp != NULL && wp[0] != L'\0' &&
+		    wp[wcslen(wp) - 1] != L'/') {
 			struct archive_wstring ws;
 
 			archive_string_init(&ws);