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 X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9432C11F64 for ; Mon, 28 Jun 2021 18:13:37 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 11CE261C6F for ; Mon, 28 Jun 2021 18:13:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 11CE261C6F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47618 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lxvlI-0004Lj-0V for qemu-devel@archiver.kernel.org; Mon, 28 Jun 2021 14:13:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45714) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxvkT-0003M4-QF for qemu-devel@nongnu.org; Mon, 28 Jun 2021 14:12:45 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:51736) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxvkQ-0007Uo-A5 for qemu-devel@nongnu.org; Mon, 28 Jun 2021 14:12:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624903960; h=from:from:reply-to:subject:subject: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=lWyJDqWjmx1sYAG9u4++6kMMMTetuRNWVfZBe6TjlD8=; b=P/dWJeYbyuUgZEKdGfa5346zHbc0AqaLJkmcyMgVzS80oEcKsOm17FJ8qik5tV7hNz42fV m3b3eBjWZFeiCLxTksCZC7lfJGRCLqNbozkG/84RRfFAc8cJiJ9POhJzUPtvH9ysDRtGm5 6cpxERhnxtf4/YWa3KXrw33d4jBqGgI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-238-ZQitZAOOPfqpKSNF59IbIg-1; Mon, 28 Jun 2021 14:12:35 -0400 X-MC-Unique: ZQitZAOOPfqpKSNF59IbIg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 08DAF100CA89; Mon, 28 Jun 2021 18:12:20 +0000 (UTC) Received: from horse.redhat.com (ovpn-115-225.rdu2.redhat.com [10.10.115.225]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3C53E6091B; Mon, 28 Jun 2021 18:12:19 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id B747022054F; Mon, 28 Jun 2021 14:12:18 -0400 (EDT) Date: Mon, 28 Jun 2021 14:12:18 -0400 From: Vivek Goyal To: "Dr. David Alan Gilbert" Subject: Re: [PATCH v7 5/7] virtiofsd: Add capability to change/restore umask Message-ID: <20210628181218.GF1803896@redhat.com> References: <20210622150852.1507204-1-vgoyal@redhat.com> <20210622150852.1507204-6-vgoyal@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=vgoyal@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=vgoyal@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.375, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-fs@redhat.com, miklos@szeredi.hu, qemu-devel@nongnu.org, lhenriques@suse.de Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Jun 28, 2021 at 05:12:13PM +0100, Dr. David Alan Gilbert wrote: > * Vivek Goyal (vgoyal@redhat.com) wrote: > > When parent directory has default acl and a file is created in that > > directory, then umask is ignored and final file permissions are > > determined using default acl instead. (man 2 umask). > > > > Currently, fuse applies the umask and sends modified mode in create > > request accordingly. fuse server can set FUSE_DONT_MASK and tell > > fuse client to not apply umask and fuse server will take care of > > it as needed. > > > > With posix acls enabled, requirement will be that we want umask > > to determine final file mode if parent directory does not have > > default acl. > > > > So if posix acls are enabled, opt in for FUSE_DONT_MASK. virtiofsd > > will set umask of the thread doing file creation. And host kernel > > should use that umask if parent directory does not have default > > acls, otherwise umask does not take affect. > > > > Miklos mentioned that we already call unshare(CLONE_FS) for > > every thread. That means umask has now become property of per > > thread and it should be ok to manipulate it in file creation path. > > > > This patch only adds capability to change umask and restore it. It > > does not enable it yet. Next few patches will add capability to enable it > > based on if user enabled posix_acl or not. > > > > This should fix fstest generic/099. > > > > Reported-by: Luis Henriques > > Signed-off-by: Vivek Goyal > > Reviewed-by: Stefan Hajnoczi > > --- > > tools/virtiofsd/passthrough_ll.c | 22 ++++++++++++++++------ > > 1 file changed, 16 insertions(+), 6 deletions(-) > > > > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c > > index 9f5cd98fb5..0c9084ea15 100644 > > --- a/tools/virtiofsd/passthrough_ll.c > > +++ b/tools/virtiofsd/passthrough_ll.c > > @@ -122,6 +122,7 @@ struct lo_inode { > > struct lo_cred { > > uid_t euid; > > gid_t egid; > > + mode_t umask; > > }; > > > > enum { > > @@ -172,6 +173,8 @@ struct lo_data { > > /* An O_PATH file descriptor to /proc/self/fd/ */ > > int proc_self_fd; > > int user_killpriv_v2, killpriv_v2; > > + /* If set, virtiofsd is responsible for setting umask during creation */ > > + bool change_umask; > > }; > > > > static const struct fuse_opt lo_opts[] = { > > @@ -1134,7 +1137,8 @@ static void lo_lookup(fuse_req_t req, fuse_ino_t parent, const char *name) > > * ownership of caller. > > * TODO: What about selinux context? > > */ > > -static int lo_change_cred(fuse_req_t req, struct lo_cred *old) > > +static int lo_change_cred(fuse_req_t req, struct lo_cred *old, > > + bool change_umask) > > { > > int res; > > > > @@ -1154,11 +1158,14 @@ static int lo_change_cred(fuse_req_t req, struct lo_cred *old) > > return errno_save; > > } > > > > + if (change_umask) { > > + old->umask = umask(req->ctx.umask); > > + } > > return 0; > > } > > > > /* Regain Privileges */ > > -static void lo_restore_cred(struct lo_cred *old) > > +static void lo_restore_cred(struct lo_cred *old, bool restore_umask) > > { > > int res; > > > > @@ -1173,6 +1180,9 @@ static void lo_restore_cred(struct lo_cred *old) > > fuse_log(FUSE_LOG_ERR, "setegid(%u): %m\n", old->egid); > > exit(1); > > } > > + > > + if (restore_umask) > > + umask(old->umask); > > } > > > > static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent, > > @@ -1202,7 +1212,7 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent, > > return; > > } > > > > - saverr = lo_change_cred(req, &old); > > + saverr = lo_change_cred(req, &old, lo->change_umask && !S_ISLNK(mode)); > > Can you explain what these ISLNK checks are for (insid mknod_symlink, so > is that always true or irrelevant?) I think I put this check in because if we are creating symlink then we don't have to change umask as symlink will always get a some fix mode (usually 777) and umask will not have an affect. So this is just an optimization to avoid switching umask in some cases. I can't think of any other reason. thanks Vivek From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 28 Jun 2021 14:12:18 -0400 From: Vivek Goyal Message-ID: <20210628181218.GF1803896@redhat.com> References: <20210622150852.1507204-1-vgoyal@redhat.com> <20210622150852.1507204-6-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Virtio-fs] [PATCH v7 5/7] virtiofsd: Add capability to change/restore umask List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: virtio-fs@redhat.com, miklos@szeredi.hu, qemu-devel@nongnu.org On Mon, Jun 28, 2021 at 05:12:13PM +0100, Dr. David Alan Gilbert wrote: > * Vivek Goyal (vgoyal@redhat.com) wrote: > > When parent directory has default acl and a file is created in that > > directory, then umask is ignored and final file permissions are > > determined using default acl instead. (man 2 umask). > > > > Currently, fuse applies the umask and sends modified mode in create > > request accordingly. fuse server can set FUSE_DONT_MASK and tell > > fuse client to not apply umask and fuse server will take care of > > it as needed. > > > > With posix acls enabled, requirement will be that we want umask > > to determine final file mode if parent directory does not have > > default acl. > > > > So if posix acls are enabled, opt in for FUSE_DONT_MASK. virtiofsd > > will set umask of the thread doing file creation. And host kernel > > should use that umask if parent directory does not have default > > acls, otherwise umask does not take affect. > > > > Miklos mentioned that we already call unshare(CLONE_FS) for > > every thread. That means umask has now become property of per > > thread and it should be ok to manipulate it in file creation path. > > > > This patch only adds capability to change umask and restore it. It > > does not enable it yet. Next few patches will add capability to enable it > > based on if user enabled posix_acl or not. > > > > This should fix fstest generic/099. > > > > Reported-by: Luis Henriques > > Signed-off-by: Vivek Goyal > > Reviewed-by: Stefan Hajnoczi > > --- > > tools/virtiofsd/passthrough_ll.c | 22 ++++++++++++++++------ > > 1 file changed, 16 insertions(+), 6 deletions(-) > > > > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c > > index 9f5cd98fb5..0c9084ea15 100644 > > --- a/tools/virtiofsd/passthrough_ll.c > > +++ b/tools/virtiofsd/passthrough_ll.c > > @@ -122,6 +122,7 @@ struct lo_inode { > > struct lo_cred { > > uid_t euid; > > gid_t egid; > > + mode_t umask; > > }; > > > > enum { > > @@ -172,6 +173,8 @@ struct lo_data { > > /* An O_PATH file descriptor to /proc/self/fd/ */ > > int proc_self_fd; > > int user_killpriv_v2, killpriv_v2; > > + /* If set, virtiofsd is responsible for setting umask during creation */ > > + bool change_umask; > > }; > > > > static const struct fuse_opt lo_opts[] = { > > @@ -1134,7 +1137,8 @@ static void lo_lookup(fuse_req_t req, fuse_ino_t parent, const char *name) > > * ownership of caller. > > * TODO: What about selinux context? > > */ > > -static int lo_change_cred(fuse_req_t req, struct lo_cred *old) > > +static int lo_change_cred(fuse_req_t req, struct lo_cred *old, > > + bool change_umask) > > { > > int res; > > > > @@ -1154,11 +1158,14 @@ static int lo_change_cred(fuse_req_t req, struct lo_cred *old) > > return errno_save; > > } > > > > + if (change_umask) { > > + old->umask = umask(req->ctx.umask); > > + } > > return 0; > > } > > > > /* Regain Privileges */ > > -static void lo_restore_cred(struct lo_cred *old) > > +static void lo_restore_cred(struct lo_cred *old, bool restore_umask) > > { > > int res; > > > > @@ -1173,6 +1180,9 @@ static void lo_restore_cred(struct lo_cred *old) > > fuse_log(FUSE_LOG_ERR, "setegid(%u): %m\n", old->egid); > > exit(1); > > } > > + > > + if (restore_umask) > > + umask(old->umask); > > } > > > > static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent, > > @@ -1202,7 +1212,7 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent, > > return; > > } > > > > - saverr = lo_change_cred(req, &old); > > + saverr = lo_change_cred(req, &old, lo->change_umask && !S_ISLNK(mode)); > > Can you explain what these ISLNK checks are for (insid mknod_symlink, so > is that always true or irrelevant?) I think I put this check in because if we are creating symlink then we don't have to change umask as symlink will always get a some fix mode (usually 777) and umask will not have an affect. So this is just an optimization to avoid switching umask in some cases. I can't think of any other reason. thanks Vivek