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 4F123C64EC4 for ; Mon, 20 Feb 2023 13:58:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232638AbjBTN60 (ORCPT ); Mon, 20 Feb 2023 08:58:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232644AbjBTN60 (ORCPT ); Mon, 20 Feb 2023 08:58:26 -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 16248A24B for ; Mon, 20 Feb 2023 05:57:55 -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 95F9060EB0 for ; Mon, 20 Feb 2023 13:57:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A549EC433EF; Mon, 20 Feb 2023 13:57:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1676901429; bh=AaIeNztZETm3XHMGdo+mMQ5+5jHu/pRFxpqdKXj9vvY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l9Pp00M+VoReSHgJd+7Q4dlt7a1iwiCkutw+CaXtwWmhul61u9858H/qllS45smJU 0SNkFE0Dq1aDbJUML5J+x2GqFM1yVbC6KH/04JumHsbpQ1TuRmjjqthvztrRZV/QSE 8+DuYNI8xkFisiv5ok/zr+WjYEgVGHbIazu5nXNs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eduard Zingerman , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.1 014/118] selftests/bpf: Verify copy_register_state() preserves parent/live fields Date: Mon, 20 Feb 2023 14:35:30 +0100 Message-Id: <20230220133600.977627419@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230220133600.368809650@linuxfoundation.org> References: <20230220133600.368809650@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: Eduard Zingerman [ Upstream commit b9fa9bc839291020b362ab5392e5f18ba79657ac ] A testcase to check that verifier.c:copy_register_state() preserves register parentage chain and livness information. Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20230106142214.1040390-3-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- .../selftests/bpf/verifier/search_pruning.c | 36 +++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/tools/testing/selftests/bpf/verifier/search_pruning.c b/tools/testing/selftests/bpf/verifier/search_pruning.c index 68b14fdfebdb1..d63fd8991b03a 100644 --- a/tools/testing/selftests/bpf/verifier/search_pruning.c +++ b/tools/testing/selftests/bpf/verifier/search_pruning.c @@ -225,3 +225,39 @@ .result_unpriv = ACCEPT, .insn_processed = 15, }, +/* The test performs a conditional 64-bit write to a stack location + * fp[-8], this is followed by an unconditional 8-bit write to fp[-8], + * then data is read from fp[-8]. This sequence is unsafe. + * + * The test would be mistakenly marked as safe w/o dst register parent + * preservation in verifier.c:copy_register_state() function. + * + * Note the usage of BPF_F_TEST_STATE_FREQ to force creation of the + * checkpoint state after conditional 64-bit assignment. + */ +{ + "write tracking and register parent chain bug", + .insns = { + /* r6 = ktime_get_ns() */ + BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns), + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), + /* r0 = ktime_get_ns() */ + BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns), + /* if r0 > r6 goto +1 */ + BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_6, 1), + /* *(u64 *)(r10 - 8) = 0xdeadbeef */ + BPF_ST_MEM(BPF_DW, BPF_REG_FP, -8, 0xdeadbeef), + /* r1 = 42 */ + BPF_MOV64_IMM(BPF_REG_1, 42), + /* *(u8 *)(r10 - 8) = r1 */ + BPF_STX_MEM(BPF_B, BPF_REG_FP, BPF_REG_1, -8), + /* r2 = *(u64 *)(r10 - 8) */ + BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_FP, -8), + /* exit(0) */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .flags = BPF_F_TEST_STATE_FREQ, + .errstr = "invalid read from stack off -8+1 size 8", + .result = REJECT, +}, -- 2.39.0