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 EBAF7223DCE; Mon, 13 Apr 2026 16:48:04 +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=1776098885; cv=none; b=ZGYuxPbPh97vs6d3xXn0U7x2KbbXBy3hToVrKAyyvcUdFlDT+yDNeIBDIBQTjasXUMH/VI49+wGZTsTGD/BAXaAiuAAiy5Xub68qzvseZgDu4YVtTPy4CBaGpmKH853VmvgyQnZgu/nrFu1ZhGZ2EL31R0tiyM/porP8T+CeXPQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776098885; c=relaxed/simple; bh=bizKiEYqvnFN0O0kEWSQTCfq0h6yjToNvUIiFQ6naxE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Vrbe0kRr0MvVKBVwlmUgArCoJF+WRMFbv0Gyuk6Ai6s3IQD0biCOGJUVcy5cwfMUmHznvEwodJM6WxIPC+JCUdMRFnc5pC5Ctvn6QtPyYPvlQeLeYqk9jsml9akldf2FgD8k6ZXGrx9TyirFG/e1NUDILArHBrQhqD1I8tLdazw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Eaeybo7E; 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="Eaeybo7E" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F464C2BCAF; Mon, 13 Apr 2026 16:48:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776098884; bh=bizKiEYqvnFN0O0kEWSQTCfq0h6yjToNvUIiFQ6naxE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Eaeybo7E3bdFEKHxR+icC+znWbKYx/ElC+WWrzXn6lfg/CUeQY05MQpuvGYUNjtak iZUxZ0a716RWw26RFgignosE27H8PWatmWgpxQMDw/i72Ln4PN0GpiUepHucQRXx7O RWDRc6LCfM80IDzp9bpcUIAycTWYzhpbZpH7uN68= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Josh Law , "Masami Hiramatsu (Google)" Subject: [PATCH 5.10 126/491] lib/bootconfig: fix snprintf truncation check in xbc_node_compose_key_after() Date: Mon, 13 Apr 2026 17:56:11 +0200 Message-ID: <20260413155823.759720109@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155819.042779211@linuxfoundation.org> References: <20260413155819.042779211@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 5.10-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 @@ -250,7 +250,7 @@ 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;