From patchwork Fri Jul 22 17:58:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 12926702 X-Patchwork-Delegate: bpf@iogearbox.net 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 DD69BC433EF for ; Fri, 22 Jul 2022 18:00:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233965AbiGVSAE (ORCPT ); Fri, 22 Jul 2022 14:00:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235960AbiGVSAD (ORCPT ); Fri, 22 Jul 2022 14:00:03 -0400 Received: from 69-171-232-181.mail-mxout.facebook.com (69-171-232-181.mail-mxout.facebook.com [69.171.232.181]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90BD47436E for ; Fri, 22 Jul 2022 11:00:02 -0700 (PDT) Received: by devbig010.atn6.facebook.com (Postfix, from userid 115148) id CC09CF52A4C1; Fri, 22 Jul 2022 10:59:47 -0700 (PDT) From: Joanne Koong To: bpf@vger.kernel.org Cc: kafai@fb.com, jolsa@kernel.org, haoluo@google.com, andrii@kernel.org, daniel@iogearbox.net, ast@kernel.org, Joanne Koong Subject: [PATCH bpf-next v2 2/2] selftests/bpf: add extra test for using dynptr data slice after release Date: Fri, 22 Jul 2022 10:58:07 -0700 Message-Id: <20220722175807.4038317-2-joannelkoong@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220722175807.4038317-1-joannelkoong@gmail.com> References: <20220722175807.4038317-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add an additional test, "data_slice_use_after_release2", for ensuring that data slices are correctly invalidated by the verifier after the dynptr whose ref obj id they track is released. In particular, this tests data slice invalidation for dynptrs located at a non-zero offset from the frame pointer. Signed-off-by: Joanne Koong Acked-by: Martin KaFai Lau --- .../testing/selftests/bpf/prog_tests/dynptr.c | 3 +- .../testing/selftests/bpf/progs/dynptr_fail.c | 38 ++++++++++++++++++- 2 files changed, 39 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c index 3c7aa82b98e2..bcf80b9f7c27 100644 --- a/tools/testing/selftests/bpf/prog_tests/dynptr.c +++ b/tools/testing/selftests/bpf/prog_tests/dynptr.c @@ -22,7 +22,8 @@ static struct { {"add_dynptr_to_map2", "invalid indirect read from stack"}, {"data_slice_out_of_bounds_ringbuf", "value is outside of the allowed memory range"}, {"data_slice_out_of_bounds_map_value", "value is outside of the allowed memory range"}, - {"data_slice_use_after_release", "invalid mem access 'scalar'"}, + {"data_slice_use_after_release1", "invalid mem access 'scalar'"}, + {"data_slice_use_after_release2", "invalid mem access 'scalar'"}, {"data_slice_missing_null_check1", "invalid mem access 'mem_or_null'"}, {"data_slice_missing_null_check2", "invalid mem access 'mem_or_null'"}, {"invalid_helper1", "invalid indirect read from stack"}, diff --git a/tools/testing/selftests/bpf/progs/dynptr_fail.c b/tools/testing/selftests/bpf/progs/dynptr_fail.c index d811cff73597..a8ee58ba3a84 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_fail.c +++ b/tools/testing/selftests/bpf/progs/dynptr_fail.c @@ -248,7 +248,7 @@ int data_slice_out_of_bounds_map_value(void *ctx) /* A data slice can't be used after it has been released */ SEC("?raw_tp/sys_nanosleep") -int data_slice_use_after_release(void *ctx) +int data_slice_use_after_release1(void *ctx) { struct bpf_dynptr ptr; struct sample *sample; @@ -272,6 +272,42 @@ int data_slice_use_after_release(void *ctx) return 0; } +/* A data slice can't be used after it has been released. + * + * This tests the case where the data slice tracks a dynptr (ptr2) + * that is at a non-zero offset from the frame pointer (ptr1 is at fp, + * ptr2 is at fp - 16). + */ +SEC("?raw_tp/sys_nanosleep") +int data_slice_use_after_release2(void *ctx) +{ + struct bpf_dynptr ptr1, ptr2; + struct sample *sample; + + bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &ptr1); + bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(*sample), 0, &ptr2); + + sample = bpf_dynptr_data(&ptr2, 0, sizeof(*sample)); + if (!sample) + goto done; + + sample->pid = 23; + + bpf_ringbuf_submit_dynptr(&ptr2, 0); + + /* this should fail */ + sample->pid = 23; + + bpf_ringbuf_submit_dynptr(&ptr1, 0); + + return 0; + +done: + bpf_ringbuf_discard_dynptr(&ptr2, 0); + bpf_ringbuf_discard_dynptr(&ptr1, 0); + return 0; +} + /* A data slice must be first checked for NULL */ SEC("?raw_tp/sys_nanosleep") int data_slice_missing_null_check1(void *ctx)