From patchwork Mon May 31 13:13:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 451261 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F950C47083 for ; Mon, 31 May 2021 13:30:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E937961420 for ; Mon, 31 May 2021 13:30:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232182AbhEaNca (ORCPT ); Mon, 31 May 2021 09:32:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:34112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232200AbhEaNa2 (ORCPT ); Mon, 31 May 2021 09:30:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5FA9A61424; Mon, 31 May 2021 13:23:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1622467385; bh=5M2+Vo6Jk3Y+bh6eAHj6OVt2po33/88yIIcYy70EeYE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cImlv3+g5dI0Lzsak1hNl70GO6zz2wVv8qy/Dv+PVELL0XlhzRXAY84CLah+mDstN 6elSJXcVt9pfijuCIAVE40D/NWx0Xdj8Hvltw9/NpYL69kKVGMn/DqWHz9a+m92xVG teisEHgjYDbNILNlipkfl4Vf0x6yQXivMPuH7fdU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Daniel Borkmann , Alexei Starovoitov , John Fastabend , Ovidiu Panait Subject: [PATCH 4.19 046/116] bpf, test_verifier: switch bpf_get_stacks 0 s> r8 test Date: Mon, 31 May 2021 15:13:42 +0200 Message-Id: <20210531130641.741241614@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210531130640.131924542@linuxfoundation.org> References: <20210531130640.131924542@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Daniel Borkmann [ no upstream commit ] Switch the comparison, so that is_branch_taken() will recognize that below branch is never taken: [...] 17: [...] R1_w=inv0 [...] R8_w=inv(id=0,smin_value=-2147483648,smax_value=-1,umin_value=18446744071562067968,var_off=(0xffffffff80000000; 0x7fffffff)) [...] 17: (67) r8 <<= 32 18: [...] R8_w=inv(id=0,smax_value=-4294967296,umin_value=9223372036854775808,umax_value=18446744069414584320,var_off=(0x8000000000000000; 0x7fffffff00000000)) [...] 18: (c7) r8 s>>= 32 19: [...] R8_w=inv(id=0,smin_value=-2147483648,smax_value=-1,umin_value=18446744071562067968,var_off=(0xffffffff80000000; 0x7fffffff)) [...] 19: (6d) if r1 s> r8 goto pc+16 [...] R1_w=inv0 [...] R8_w=inv(id=0,smin_value=-2147483648,smax_value=-1,umin_value=18446744071562067968,var_off=(0xffffffff80000000; 0x7fffffff)) [...] [...] Currently we check for is_branch_taken() only if either K is source, or source is a scalar value that is const. For upstream it would be good to extend this properly to check whether dst is const and src not. For the sake of the test_verifier, it is probably not needed here: # ./test_verifier 101 #101/p bpf_get_stack return R0 within range OK Summary: 1 PASSED, 0 SKIPPED, 0 FAILED I haven't seen this issue in test_progs* though, they are passing fine: # ./test_progs-no_alu32 -t get_stack Switching to flavor 'no_alu32' subdirectory... #20 get_stack_raw_tp:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED # ./test_progs -t get_stack #20 get_stack_raw_tp:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: John Fastabend Signed-off-by: Greg Kroah-Hartman [OP: backport to 4.19] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/bpf/test_verifier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -12263,7 +12263,7 @@ static struct bpf_test tests[] = { BPF_MOV64_REG(BPF_REG_8, BPF_REG_0), BPF_ALU64_IMM(BPF_LSH, BPF_REG_8, 32), BPF_ALU64_IMM(BPF_ARSH, BPF_REG_8, 32), - BPF_JMP_REG(BPF_JSGT, BPF_REG_1, BPF_REG_8, 16), + BPF_JMP_REG(BPF_JSLT, BPF_REG_8, BPF_REG_1, 16), BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8), BPF_MOV64_REG(BPF_REG_2, BPF_REG_7), BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_8),