From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 1162F3A7839 for ; Mon, 22 Jun 2026 09:10:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782119428; cv=none; b=qA1I/T37lxzKf+BEsQejOcCo8PWCc/T/O7VCo2/36sQyGLx0uch0Hro2qspsfkwzvwShL9ed9tlRNGqZAEoWTvLP0PRoR6qV7tnaDGZkmxJup+eK5CXB3hFRFPVe5tSM9Mdznu/dJYXLIbJwmMbynSx5t1ZQICLp2lgaTVQefKs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782119428; c=relaxed/simple; bh=svxPEDSaFUJW1uCJX3VJjP5uyQ25iA0A76oqVEXg0hQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MfuA4q/maApmj/O/Jys9lpOsPKf8meVREiMDBMeOZyf/9dEret6hJnD95wBsgaMhnmRtNG73hGX8LJ0893OMrcdA7z64HJ60tr84aJ/Ukub3Ncu7x2NuBSPT45PZW0NuE7ccO7x9DMtxkKDxf5XHjuUz9iHHTwVJFObVcDx1qlE= 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=O4wuqN/d; arc=none smtp.client-ip=170.10.129.124 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="O4wuqN/d" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782119426; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qc3AUaJBiNCkiBRvrTGrdtukzI4PlxpQ5/Yzj4K7t9M=; b=O4wuqN/dCw9atOJVPd7XGAj0cI3KwqFFM7ZqtLfaKfsdy6daBw6/gXjKAz3P6YtEvocv1m 2T8jg+/syT6wIRyrs3pIXeb5ux68unBTHpy/rZ2kXvCt6RomskLXfZ4gQq7QHGSGROAOL0 D8SB1nErdhwO2h7i0g3zkEctxBe4+Nk= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-663-xO3PVpK8NES8cNOpfXoSwg-1; Mon, 22 Jun 2026 05:10:23 -0400 X-MC-Unique: xO3PVpK8NES8cNOpfXoSwg-1 X-Mimecast-MFC-AGG-ID: xO3PVpK8NES8cNOpfXoSwg_1782119422 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E37711805C30; Mon, 22 Jun 2026 09:10:21 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.44.48.242]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 0983D1953946; Mon, 22 Jun 2026 09:10:19 +0000 (UTC) From: David Howells To: Christian Brauner Cc: David Howells , Marc Dionne , linux-afs@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 19/21] afs: Fix premature cell exposure through /afs Date: Mon, 22 Jun 2026 10:08:53 +0100 Message-ID: <20260622090856.2746629-20-dhowells@redhat.com> In-Reply-To: <20260622090856.2746629-1-dhowells@redhat.com> References: <20260622090856.2746629-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 AFS cell records are prematurely exposured through the /afs dynamic root by virtue of adding them immediately to the net->cells_dyn_ino IDR when the cell is allocated rather than when it is added to the lookup tree. This allows a candidate record to be accessed, even if it's actually a duplicate or not published yet. Fix this by not adding the cell to cells_dyn_ino until it's confirmed non-duplicate and is being published. A flag is then used to record whether it is added to the IDR to make removal from the IDR conditional. Closes: https://sashiko.dev/#/patchset/20260618155141.2513212-1-dhowells%40redhat.com Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org --- fs/afs/cell.c | 27 +++++++++++++++++---------- fs/afs/internal.h | 1 + 2 files changed, 18 insertions(+), 10 deletions(-) diff --git a/fs/afs/cell.c b/fs/afs/cell.c index 9d8937ae24e2..47a2645768d7 100644 --- a/fs/afs/cell.c +++ b/fs/afs/cell.c @@ -205,14 +205,7 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net, cell->dns_source = vllist->source; cell->dns_status = vllist->status; smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */ - down_write(&net->cells_lock); - ret = idr_alloc_cyclic(&net->cells_dyn_ino, cell, - 2, INT_MAX / 2, GFP_KERNEL); - up_write(&net->cells_lock); - if (ret < 0) - goto error; atomic_inc(&net->cells_outstanding); - cell->dynroot_ino = ret; cell->debug_id = atomic_inc_return(&cell_debug_id); trace_afs_cell(cell->debug_id, 1, 0, afs_cell_trace_alloc); @@ -306,6 +299,13 @@ struct afs_cell *afs_lookup_cell(struct afs_net *net, goto cell_already_exists; } + ret = idr_alloc_cyclic(&net->cells_dyn_ino, candidate, + 2, INT_MAX / 2, GFP_KERNEL); + if (ret < 0) + goto cant_alloc_ino; + candidate->dynroot_ino = ret; + set_bit(AFS_CELL_FL_HAVE_INO, &candidate->flags); + cell = candidate; candidate = NULL; afs_use_cell(cell, trace); @@ -380,6 +380,11 @@ struct afs_cell *afs_lookup_cell(struct afs_net *net, _leave(" = %p [cell]", cell); return cell; +cant_alloc_ino: + up_write(&net->cells_lock); + afs_put_cell(candidate, afs_cell_trace_put_candidate); + goto error_noput; + cell_already_exists: _debug("cell exists"); cell = cursor; @@ -596,9 +601,11 @@ static void afs_destroy_cell_work(struct work_struct *work) timer_delete_sync(&cell->management_timer); cancel_work_sync(&cell->manager); - down_write(&cell->net->cells_lock); - idr_remove(&cell->net->cells_dyn_ino, cell->dynroot_ino); - up_write(&cell->net->cells_lock); + if (test_bit(AFS_CELL_FL_HAVE_INO, &cell->flags)) { + down_write(&cell->net->cells_lock); + idr_remove(&cell->net->cells_dyn_ino, cell->dynroot_ino); + up_write(&cell->net->cells_lock); + } call_rcu(&cell->rcu, afs_cell_destroy); } diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 785c646856d7..601f01e5c15f 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -388,6 +388,7 @@ struct afs_cell { #define AFS_CELL_FL_NO_GC 0 /* The cell was added manually, don't auto-gc */ #define AFS_CELL_FL_DO_LOOKUP 1 /* DNS lookup requested */ #define AFS_CELL_FL_CHECK_ALIAS 2 /* Need to check for aliases */ +#define AFS_CELL_FL_HAVE_INO 3 /* Have dynroot_ino */ enum afs_cell_state state; short error; enum dns_record_source dns_source:8; /* Latest source of data from lookup */