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 E5C2FC7EE21 for ; Wed, 3 May 2023 00:29:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229478AbjECA31 (ORCPT ); Tue, 2 May 2023 20:29:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229475AbjECA30 (ORCPT ); Tue, 2 May 2023 20:29:26 -0400 Received: from out-44.mta0.migadu.com (out-44.mta0.migadu.com [91.218.175.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66E6E1FFB for ; Tue, 2 May 2023 17:29:25 -0700 (PDT) Message-ID: <9cc9a5f6-35cd-cfa3-8034-18dac9f20d6f@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1683073763; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7iRyZUBjp4T9gxPWsguSElMXmMNkIz9bGnF8tC9851U=; b=DN+J/mOl9Mv3OE8ka3YRhNUKlaXZC4h4ItXVr9o4kVK3Y44M6YLWivlpTF6ySTUGEQ9M+/ 7L6OIP2CsNEBPdYtQY2GJ9BeflfHovLru0YBdYI3MlVjim6QW13qOTxU7OgGe7GD2FkFs1 Z9Kzs8NCcdntWHIufHi3vacGxT5ZoHo= Date: Tue, 2 May 2023 17:29:19 -0700 MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v3 2/4] selftests/bpf: Update EFAULT {g,s}etsockopt selftests Content-Language: en-US To: Stanislav Fomichev Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, haoluo@google.com, jolsa@kernel.org, bpf@vger.kernel.org References: <20230501194825.2864150-1-sdf@google.com> <20230501194825.2864150-3-sdf@google.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20230501194825.2864150-3-sdf@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 5/1/23 12:48 PM, Stanislav Fomichev wrote: > Instead of assuming EFAULT, let's assume the BPF program's > output is ignored. > > Remove "getsockopt: deny arbitrary ctx->retval" because it > was actually testing optlen. We have separate set of tests > for retval. > > Signed-off-by: Stanislav Fomichev > --- > .../selftests/bpf/prog_tests/sockopt.c | 98 +++++++++++++++++-- > 1 file changed, 92 insertions(+), 6 deletions(-) > > diff --git a/tools/testing/selftests/bpf/prog_tests/sockopt.c b/tools/testing/selftests/bpf/prog_tests/sockopt.c > index aa4debf62fc6..a7bc9dc93ce0 100644 > --- a/tools/testing/selftests/bpf/prog_tests/sockopt.c > +++ b/tools/testing/selftests/bpf/prog_tests/sockopt.c > @@ -5,6 +5,10 @@ > static char bpf_log_buf[4096]; > static bool verbose; > > +#ifndef PAGE_SIZE > +#define PAGE_SIZE 4096 > +#endif > + > enum sockopt_test_error { > OK = 0, > DENY_LOAD, > @@ -273,10 +277,30 @@ static struct sockopt_test { > .error = EFAULT_GETSOCKOPT, > }, > { > - .descr = "getsockopt: deny arbitrary ctx->retval", > + .descr = "getsockopt: ignore >PAGE_SIZE optlen", > .insns = { > - /* ctx->retval = 123 */ > - BPF_MOV64_IMM(BPF_REG_0, 123), > + /* write 0xFF to the first optval byte */ > + > + /* r6 = ctx->optval */ > + BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, > + offsetof(struct bpf_sockopt, optval)), > + /* r2 = ctx->optval */ > + BPF_MOV64_REG(BPF_REG_2, BPF_REG_6), > + /* r6 = ctx->optval + 1 */ > + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 1), > + > + /* r7 = ctx->optval_end */ > + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_1, > + offsetof(struct bpf_sockopt, optval_end)), > + > + /* if (ctx->optval + 1 <= ctx->optval_end) { */ > + BPF_JMP_REG(BPF_JGT, BPF_REG_6, BPF_REG_7, 1), > + /* ctx->optval[0] = 0xF0 */ > + BPF_ST_MEM(BPF_B, BPF_REG_2, 0, 0xFF), > + /* } */ > + > + /* ctx->retval = 0 */ > + BPF_MOV64_IMM(BPF_REG_0, 0), This is an interesting test case. One more question just came to my mind, does it make sense to also ignore the bpf-prog's 'ctx->retval = 0' in getsockopt considering its optval change has already been ignored. Something like: if (optval && (ctx.optlen > max_optlen || ctx.optlen < 0)) { if (orig_optlen > PAGE_SIZE && ctx.optlen >= 0) { pr_info_once("bpf getsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n", ctx.optlen, max_optlen); ret = retval; goto out; } ret = -EFAULT; goto out; } > BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, > offsetof(struct bpf_sockopt, retval)), > > @@ -287,9 +311,10 @@ static struct sockopt_test { > .attach_type = BPF_CGROUP_GETSOCKOPT, > .expected_attach_type = BPF_CGROUP_GETSOCKOPT, > > - .get_optlen = 64, > - > - .error = EFAULT_GETSOCKOPT, > + .get_level = 1234, > + .get_optname = 5678, > + .get_optval = {}, /* the changes are ignored */ > + .get_optlen = PAGE_SIZE + 1, > } > > + if (optlen > sizeof(test->get_optval)) > + optlen = sizeof(test->get_optval); > + > if (memcmp(optval, test->get_optval, optlen) != 0) { > errno = 0; > log_err("getsockopt returned unexpected optval");