From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.7 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id BAA187D90D for ; Wed, 17 Jul 2019 04:31:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725890AbfGQEb3 (ORCPT ); Wed, 17 Jul 2019 00:31:29 -0400 Received: from mga03.intel.com ([134.134.136.65]:20052 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725799AbfGQEb3 (ORCPT ); Wed, 17 Jul 2019 00:31:29 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Jul 2019 21:31:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,272,1559545200"; d="scan'208";a="251375368" Received: from ngote-system-product-name.iind.intel.com ([10.106.124.92]) by orsmga001.jf.intel.com with ESMTP; 16 Jul 2019 21:31:24 -0700 From: NitinGote To: joe@perches.com, corbet@lwn.net Cc: akpm@linux-foundation.org, apw@canonical.com, keescook@chromium.org, linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com, Nitin Gote Subject: [PATCH v5] Documentation/checkpatch: Prefer strscpy/strscpy_pad over strcpy/strlcpy/strncpy Date: Wed, 17 Jul 2019 10:00:05 +0530 Message-Id: <20190717043005.19627-1-nitin.r.gote@intel.com> X-Mailer: git-send-email 2.17.1 Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Nitin Gote Added check in checkpatch.pl to 1. Deprecate strcpy() in favor of strscpy(). 2. Deprecate strlcpy() in favor of strscpy(). 3. Deprecate strncpy() in favor of strscpy() or strscpy_pad(). Updated strncpy() section in Documentation/process/deprecated.rst to cover strscpy_pad() case. Signed-off-by: Nitin Gote --- Documentation/process/deprecated.rst | 6 +++--- scripts/checkpatch.pl | 24 ++++++++++++++++++++++++ 2 files changed, 27 insertions(+), 3 deletions(-) diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst index 49e0f64a3427..c348ef9d44f5 100644 --- a/Documentation/process/deprecated.rst +++ b/Documentation/process/deprecated.rst @@ -93,9 +93,9 @@ will be NUL terminated. This can lead to various linear read overflows and other misbehavior due to the missing termination. It also NUL-pads the destination buffer if the source contents are shorter than the destination buffer size, which may be a needless performance penalty for callers using -only NUL-terminated strings. The safe replacement is :c:func:`strscpy`. -(Users of :c:func:`strscpy` still needing NUL-padding will need an -explicit :c:func:`memset` added.) +only NUL-terminated strings. In this case, the safe replacement is +strscpy(). If, however, the destination buffer still needs NUL-padding, +the safe replacement is strscpy_pad(). If a caller is using non-NUL-terminated strings, :c:func:`strncpy()` can still be used, but destinations should be marked with the `__nonstring diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index bb28b178d929..1bb12127115d 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -605,6 +605,20 @@ foreach my $entry (keys %deprecated_apis) { } $deprecated_apis_search = "(?:${deprecated_apis_search})"; +our %deprecated_string_apis = ( + "strcpy" => "strscpy", + "strlcpy" => "strscpy", + "strncpy" => "strscpy, strscpy_pad or for non-NUL-terminated strings, strncpy() can still be used, but destinations should be marked with __nonstring", +); + +#Create a search pattern for all these strings apis to speed up a loop below +our $deprecated_string_apis_search = ""; +foreach my $entry (keys %deprecated_string_apis) { + $deprecated_string_apis_search .= '|' if ($deprecated_string_apis_search ne ""); + $deprecated_string_apis_search .= $entry; +} +$deprecated_string_apis_search = "(?:${deprecated_string_apis_search})"; + our $mode_perms_world_writable = qr{ S_IWUGO | S_IWOTH | @@ -6446,6 +6460,16 @@ sub process { "Deprecated use of '$deprecated_api', prefer '$new_api' instead\n" . $herecurr); } +# check for string deprecated apis + if ($line =~ /\b($deprecated_string_apis_search)\b\s*\(/) { + my $deprecated_string_api = $1; + my $new_api = $deprecated_string_apis{$deprecated_string_api}; + my $msg_level = \&WARN; + $msg_level = \&CHK if ($file); + &{$msg_level}("DEPRECATED_API", + "Deprecated use of '$deprecated_string_api', prefer '$new_api' instead\n" . $herecurr); + } + # check for various structs that are normally const (ops, kgdb, device_tree) # and avoid what seem like struct definitions 'struct foo {' if ($line !~ /\bconst\b/ && -- 2.17.1