From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3BCB8C3DA78 for ; Tue, 17 Jan 2023 08:27:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236086AbjAQI1c (ORCPT ); Tue, 17 Jan 2023 03:27:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40014 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235811AbjAQI11 (ORCPT ); Tue, 17 Jan 2023 03:27:27 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 098A610C4; Tue, 17 Jan 2023 00:27:25 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 8821E38128; Tue, 17 Jan 2023 08:27:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1673944044; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0iuG7PkMYKf7+8R4JHptOHZGwCBSRhIIXJ2tXnim9Ps=; b=NXJX/oGHZg/1ODfYgWCcmn+0wwahKQ7zQkXRd5DSD1mFUmbxeTWNWJ9JynfiA54gY3gsgT A0jT5X2CV4slDvfBntHDytf0JyN4M8tUzCO97VNpwARYJEmqu/iB5PS1eqm8ihKjP+yROz TGVleYHmmK6G0PLGwP9ur+XbG7/8n+o= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1673944044; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0iuG7PkMYKf7+8R4JHptOHZGwCBSRhIIXJ2tXnim9Ps=; b=m+2JALH66lcQBqsBJFp+2YpheI9qlODjz1YCYeTugQ4orbs17m1hlVFr2Am4CoUB9w94VU E6i84SCD+FBiemCA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 796E11390C; Tue, 17 Jan 2023 08:27:24 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 4aCKHexbxmNxVQAAMHmgww (envelope-from ); Tue, 17 Jan 2023 08:27:24 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id BDF5FA06B2; Tue, 17 Jan 2023 09:27:23 +0100 (CET) Date: Tue, 17 Jan 2023 09:27:23 +0100 From: Jan Kara To: Richard Guy Briggs Cc: Jan Kara , Linux-Audit Mailing List , LKML , linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, Paul Moore , Eric Paris , Steve Grubb , Amir Goldstein Subject: Re: [PATCH v5 2/3] fanotify: define struct members to hold response decision context Message-ID: <20230117082723.7g3ig6ernoslt7ub@quack3> References: <45da8423b9b1e8fc7abd68cd2269acff8cf9022a.1670606054.git.rgb@redhat.com> <20221216164342.ojcbdifdmafq5njw@quack3> <20230103124201.iopasddbtb6vi362@quack3> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 16-01-23 15:42:29, Richard Guy Briggs wrote: > On 2023-01-03 13:42, Jan Kara wrote: > > On Thu 22-12-22 15:47:21, Richard Guy Briggs wrote: > > > > > + > > > > > + if (info_len != sizeof(*friar)) > > > > > + return -EINVAL; > > > > > + > > > > > + if (copy_from_user(friar, info, sizeof(*friar))) > > > > > + return -EFAULT; > > > > > + > > > > > + if (friar->hdr.type != FAN_RESPONSE_INFO_AUDIT_RULE) > > > > > + return -EINVAL; > > > > > + if (friar->hdr.pad != 0) > > > > > + return -EINVAL; > > > > > + if (friar->hdr.len != sizeof(*friar)) > > > > > + return -EINVAL; > > > > > + > > > > > + return info_len; > > > > > +} > > > > > + > > > > > > > > ... > > > > > > > > > @@ -327,10 +359,18 @@ static int process_access_response(struct fsnotify_group *group, > > > > > return -EINVAL; > > > > > } > > > > > > > > > > - if (fd < 0) > > > > > + if ((response & FAN_AUDIT) && !FAN_GROUP_FLAG(group, FAN_ENABLE_AUDIT)) > > > > > return -EINVAL; > > > > > > > > > > - if ((response & FAN_AUDIT) && !FAN_GROUP_FLAG(group, FAN_ENABLE_AUDIT)) > > > > > + if (response & FAN_INFO) { > > > > > + ret = process_access_response_info(fd, info, info_len, &friar); > > > > > + if (ret < 0) > > > > > + return ret; > > > > > + } else { > > > > > + ret = 0; > > > > > + } > > > > > + > > > > > + if (fd < 0) > > > > > return -EINVAL; > > > > > > > > And here I'd do: > > > > > > > > if (fd == FAN_NOFD) > > > > return 0; > > > > if (fd < 0) > > > > return -EINVAL; > > > > > > > > As we talked in previous revisions we'd specialcase FAN_NOFD to just verify > > > > extra info is understood by the kernel so that application writing fanotify > > > > responses has a way to check which information it can provide to the > > > > kernel. > > > > > > The reason for including it in process_access_response_info() is to make > > > sure that it is included in the FAN_INFO case to detect this extension. > > > If it were included here > > > > I see what you're getting at now. So the condition > > > > if (fd == FAN_NOFD) > > return 0; > > > > needs to be moved into > > > > if (response & FAN_INFO) > > > > branch after process_access_response_info(). I still prefer to keep it > > outside of the process_access_response_info() function itself as it looks > > more logical to me. Does it address your concerns? > > Ok. Note that this does not return zero to userspace, since this > function's return value is added to the size of the struct > fanotify_response when there is no error. Right, good point. 0 is not a good return value in this case. > For that reason, I think it makes more sense to return -ENOENT, or some > other unused error code that fits, unless you think it is acceptable to > return sizeof(struct fanotify_response) when FAN_INFO is set to indicate > this. Yeah, my intention was to indicate "success" to userspace so I'd like to return whatever we return for the case when struct fanotify_response is accepted for a normal file descriptor - looks like info_len is the right value. Thanks! Honza -- Jan Kara SUSE Labs, CR