From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 571CC26B95D for ; Tue, 6 May 2025 10:26:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746527209; cv=none; b=UoYrQmy6arKyKgvPPZQ7xdTfcfokInMS0UkX9YZtMNG5SPtgDfs7EvxurSMdDGTSiGftd51ilFr9ya++rnJOH83232dTAm81Ww06e8ECEsHgRyKcADJ5eVwt29W0Ih5pzRe/XwdYdvevknNZDwrfcZulA7aRY9+bFD0Y8YFX+yQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746527209; c=relaxed/simple; bh=1Ivtt5aDW1FFmaK6JlMxYyI8tpl1f+b9vgZYtmbilvE=; h=From:In-Reply-To:References:To:Cc:Subject:MIME-Version: Content-Type:Date:Message-ID; b=Nd2jlHiqiRhBCJYQr+Yr25v6mpKE1qaXPuAgVIUb0PBgfy2zC+ayOiw5K2bMetg/9Wh75cajZ6IvtHguwNOlfgDBM0Cu0y9e9Z3YUbrfZyCywVYmPZ6NvEkL3ushqW8SN7myxQBrtTmHBvvNsGRgi+0TvzL/8LTaeb2qTiDwZeM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Q4IahJjG; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Q4IahJjG" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1746527207; 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=ldh2ZjQIYGdGGzK49enEKH+FzA5Hf8dgiRrydZ2YEkY=; b=Q4IahJjGpQ7aVNpC3p2vdx7NBsw5bZ01ri2yl5Y3I0phL30hOAWQjnaDLfgyj6YDbiYXUA 0yOuI1J3RuxCuvdVANha0+DVRoFA5J0fE7VL47jGpKf51vizcayBbHSTOsoKZABys8dTT5 EsRUTZjW2rdHfWlfyOY5mW/eZQJS9gE= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-402-Owsc9BgwOOK2xVtAbikYmA-1; Tue, 06 May 2025 06:26:44 -0400 X-MC-Unique: Owsc9BgwOOK2xVtAbikYmA-1 X-Mimecast-MFC-AGG-ID: Owsc9BgwOOK2xVtAbikYmA_1746527202 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AF1EB1955D52; Tue, 6 May 2025 10:26:41 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.188]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 15C0519560AF; Tue, 6 May 2025 10:26:36 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20250505-erproben-zeltlager-4c16f07b96ae@brauner> References: <20250505-erproben-zeltlager-4c16f07b96ae@brauner> <433928.1745944651@warthog.procyon.org.uk> To: Christian Brauner Cc: dhowells@redhat.com, Alexander Viro , Etienne Champetier , Marc Dionne , Jeffrey Altman , Chet Ramey , Steve French , linux-afs@lists.infradead.org, openafs-devel@openafs.org, linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] afs, bash: Fix open(O_CREAT) on an extant AFS file in a sticky dir Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1209710.1746527190.1@warthog.procyon.org.uk> Date: Tue, 06 May 2025 11:26:30 +0100 Message-ID: <1209711.1746527190@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Christian Brauner wrote: > > However, the bash work around is going to be removed: > > Why is it removed? That's a very strange comment: Because it makes bash output redirection work differently to other programs, I would guess. It's actually a simple security check to work around (just retry the open() with O_CREAT dropped) - however, it does expose an... error, I suppose, in the Linux kernel: namely that the VFS itself is treating foreign files as if they had local system ownership. We have the ->permission() inode op for this reason (I presume) - but that only applies to certain checks. The VFS must not assume that it can interpret i_uid and i_gid on an inode and must not assume that it can compare them to current->fsuid and current->fs_gid. Now, in my patch, I added two inode ops because they VFS code involved makes two distinct evaluations and so I made an op for each and, as such, those evaluations may be applicable elsewhere, but I could make a combined op that handles that specific situation instead. David