From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8FF133B27C1; Mon, 23 Mar 2026 14:41:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774276862; cv=none; b=INenpmmjNDsy6noxdWgvB4fWIwVms32vojCRhidXyQ7TRRoFlhaoaZOzCAFyyt2dSXKcIkCpzBKHYtCXrkC4PgoJaUuBnajnEk6J2BUty405aZmJx2xQo0HyZw44Rw01twxeFwHftKoO5Fx+juPPEJjNNJN9LbBfrSDlMvopCPg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774276862; c=relaxed/simple; bh=L6IJcBX5zoCCMVdNCUtBRC6IIQrI5VBhdd1BX/rAejA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fOHOx2EUGbNZ1EWbdv3iOx6BANpjXmuEkCs2PyIMajVFgggcdI8RZ4nW7ONk2SC2p8S5dBfJWfuhMH1SuQ8l1w4wqb2M0KQ7L7+ETh2hh9jpVqaeoZ/2wm1bD0P1L5z0OdhBF4NfIs4LQ08E3RRnvSboSH3yOd5I1kUAJodG1i0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MJN30IkY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="MJN30IkY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29EDFC2BCB5; Mon, 23 Mar 2026 14:41:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774276862; bh=L6IJcBX5zoCCMVdNCUtBRC6IIQrI5VBhdd1BX/rAejA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MJN30IkYyy1LFdW3BewrFygF/I239z0sWZPG8H85fRAcfgg4cqW6I6frbwlnRjEQ0 FZiz9CQxtzEF6x7LTo3BJQhpPUF516cfQxq6Og7sRE6yD3G0ZtS4m3QBWVPdvh1vI8 stGQt4QosT85JmzJ38dysCrE11rwA6qFgWkctlEM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Josh Law , "Masami Hiramatsu (Google)" Subject: [PATCH 6.12 195/460] lib/bootconfig: fix snprintf truncation check in xbc_node_compose_key_after() Date: Mon, 23 Mar 2026 14:43:11 +0100 Message-ID: <20260323134531.338512938@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134526.647552166@linuxfoundation.org> References: <20260323134526.647552166@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josh Law commit 1120a36bb1e9b9e22de75ecb4ef0b998f73a97f1 upstream. snprintf() returns the number of characters that would have been written excluding the NUL terminator. Output is truncated when the return value is >= the buffer size, not just > the buffer size. When ret == size, the current code takes the non-truncated path, advancing buf by ret and reducing size to 0. This is wrong because the output was actually truncated (the last character was replaced by NUL). Fix by using >= so the truncation path is taken correctly. Link: https://lore.kernel.org/all/20260312191143.28719-4-objecting@objecting.org/ Fixes: 76db5a27a827 ("bootconfig: Add Extra Boot Config support") Cc: stable@vger.kernel.org Signed-off-by: Josh Law Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman --- lib/bootconfig.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/lib/bootconfig.c +++ b/lib/bootconfig.c @@ -316,7 +316,7 @@ int __init xbc_node_compose_key_after(st depth ? "." : ""); if (ret < 0) return ret; - if (ret > size) { + if (ret >= size) { size = 0; } else { size -= ret;