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 A5145C43217 for ; Mon, 14 Nov 2022 12:53:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237474AbiKNMxl (ORCPT ); Mon, 14 Nov 2022 07:53:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237477AbiKNMxk (ORCPT ); Mon, 14 Nov 2022 07:53:40 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAFE4B4BA for ; Mon, 14 Nov 2022 04:53:39 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 684C16117B for ; Mon, 14 Nov 2022 12:53:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70590C433D6; Mon, 14 Nov 2022 12:53:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1668430418; bh=vqoqU349YzzvV+0xXowfbLnhc9WiZJE4c2kSoVGoJmA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Uxq/lBYYufRAAnpBg03wZoIiwEe6zNkW6ZL3SO5ACfWRa7fz+ZjouO5hiwH12Si8V f3r2dsFntChbimC4jWfOloEzVvRNwisdM2AIe6Frs20Ib+3DsM2cEnaYezL/f7bWoY YB2b5xMkCdw2G16UfCAwrmalCuWlQf+MjuG8+9IY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Youlin Li , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.15 022/131] bpf: Fix wrong reg type conversion in release_reference() Date: Mon, 14 Nov 2022 13:44:51 +0100 Message-Id: <20221114124449.645454889@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221114124448.729235104@linuxfoundation.org> References: <20221114124448.729235104@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Youlin Li [ Upstream commit f1db20814af532f85e091231223e5e4818e8464b ] Some helper functions will allocate memory. To avoid memory leaks, the verifier requires the eBPF program to release these memories by calling the corresponding helper functions. When a resource is released, all pointer registers corresponding to the resource should be invalidated. The verifier use release_references() to do this job, by apply __mark_reg_unknown() to each relevant register. It will give these registers the type of SCALAR_VALUE. A register that will contain a pointer value at runtime, but of type SCALAR_VALUE, which may allow the unprivileged user to get a kernel pointer by storing this register into a map. Using __mark_reg_not_init() while NOT allow_ptr_leaks can mitigate this problem. Fixes: fd978bf7fd31 ("bpf: Add reference tracking to verifier") Signed-off-by: Youlin Li Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20221103093440.3161-1-liulin063@gmail.com Signed-off-by: Sasha Levin --- kernel/bpf/verifier.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 96f317c494d9..8a73a165ac76 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5686,8 +5686,12 @@ static int release_reference(struct bpf_verifier_env *env, return err; bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({ - if (reg->ref_obj_id == ref_obj_id) - __mark_reg_unknown(env, reg); + if (reg->ref_obj_id == ref_obj_id) { + if (!env->allow_ptr_leaks) + __mark_reg_not_init(env, reg); + else + __mark_reg_unknown(env, reg); + } })); return 0; -- 2.35.1