From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 961091D798E; Sat, 12 Sep 2026 17:01:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789232512; cv=none; b=seKjNAXJR3OVnA8muLTukqu2Ylh4x4HmDtEvCbMRUOpT+YeFzW9bj8tbfo9tJs6i5/9mDbUHTVr4Qu+C2cZ/esdMI0r0bCHzQ6y05l8lMdEounR/mM80tuGglmnJKlSVSlrQn3Vp1QZk3muw+nkcdfhvGEJqH0d6t5MBX1cL5Uc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789232512; c=relaxed/simple; bh=OgdXgB9ZvdkTGnuc+8/A+8ixBcOs1NFoLIkBGiDJHgk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TrIXU6TmXYGnLFUSPb8vEgWRsihlI1B8hDCS0SCctwQZNoBhZRGQQfjIbrwA8lNxW1+VzKz2Ds0mgqo4YiCU6DCUxJUpwCJxE8F8nhL5DbKjr7OOOgsZT91C+HBi++dlvZPaHFF2QcuX7YdLFTFSy0RjV/1yiDNIZQtwTTwV140= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xlxSYeAH; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xlxSYeAH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6AE651F000FF; Sat, 12 Sep 2026 17:01:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789232511; bh=AXp2qtC42YVb98ZSBqLX7Q3j7lRYPbmNWeUDlVzPjq4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=xlxSYeAHBTAfPt1nrMbQfN7qkQZIJrVxSnvyH+sCrqGYW8R1yth9N5E/KMXPUV5fg iKDwYlP+sc4pp90Iu9bQovXX49bnmPy0h6sYyvq/BEri7cCqrzqTfkams4iQynDHJw BeN0nEo6xifzmbCfYs0gIV9CJCSIiRsNJ/wBTZPg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vincent Mailhol , Kees Cook , Andrew Morton Subject: [PATCH 5.15 025/935] lib/ucs2_string.c: fix out-of-bounds read in ucs2_strnlen() Date: Sat, 12 Sep 2026 08:50:55 +0200 Message-ID: <20260912065527.416004778@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065526.833703348@linuxfoundation.org> References: <20260912065526.833703348@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vincent Mailhol commit cec0d03fe785380540dc1b4d07c80f67ae2ffc78 upstream. Patch series "lib/ucs2_string.c: fix out-of-bounds read in ucs2_strnlen()", v2. This series fixes an off-by-one out-of-bounds read in ucs2_strnlen(). The first patch is the real fix, the second patch comes as a bonus and fixes the code indentation. This patch (of 2): ucs2_strnlen() checks the current character before checking whether the caller-provided maximum length has been reached. If the input is not NUL-terminated within that bound, the loop can read one ucs2_char_t past the limit. Test the length before dereferencing to prevent an off-by-one out-of-bounds read. Link: https://lore.kernel.org/20260723-fix-ucs2_strnlen-v2-0-9ea94e32a358@kernel.org Link: https://lore.kernel.org/20260723-fix-ucs2_strnlen-v2-1-9ea94e32a358@kernel.org Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Vincent Mailhol Cc: Kees Cook Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- lib/ucs2_string.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/lib/ucs2_string.c +++ b/lib/ucs2_string.c @@ -8,7 +8,7 @@ ucs2_strnlen(const ucs2_char_t *s, size_ { unsigned long length = 0; - while (*s++ != 0 && length < maxlength) + while (length < maxlength && *s++ != 0) length++; return length; }