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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 84732C4360C for ; Tue, 8 Oct 2019 18:01:19 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5E5BC21721 for ; Tue, 8 Oct 2019 18:01:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OQ6JhQvz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5E5BC21721 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=REJU1e4mzIh4YnhosTv52GnWA6MMRxQYZYSJuAO+PPI=; b=OQ6JhQvzC9CFT1 7nzcG4pd1Ie7IeTDTQvH1dvb6hCNZxHGevlbtAolJQtpckdgeuLFwWWkOhJv2/d1rMjkdOkyZ4VVq dDyhNP8sW+3iCsAeooq5QTxpQJufxHC1tuaDVW+SdtfNvGR0c6edRtw8TlzqtwJTpJskLAc4B12bP uZ2Q4P7WoaVxY64xgKItc9iWc+gOWqaLbcQpdVQx6cZt41py4ybEVRZeof99i+ukC4nKRHZBY28vP olLXWov9y8IyfYtYYQT1xBFk6y+n/ai0huWVLRTh2BgrytR4pHtulVdNcKgxCB73QCgYO/+RmwP7I 22B6r+wqaoShQivxgXEw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iHtnK-0005Iq-4d; Tue, 08 Oct 2019 18:01:10 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iHtnG-0005IP-EJ for linux-arm-kernel@lists.infradead.org; Tue, 08 Oct 2019 18:01:08 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 626BF15BE; Tue, 8 Oct 2019 11:01:05 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 78E073F6C4; Tue, 8 Oct 2019 11:01:04 -0700 (PDT) Date: Tue, 8 Oct 2019 19:01:02 +0100 From: Dave Martin To: Cristian Marussi Subject: Re: [PATCH v7 06/11] kselftest: arm64: fake_sigreturn_bad_magic Message-ID: <20191008180102.GX27757@arm.com> References: <20191007182954.25730-1-cristian.marussi@arm.com> <20191007182954.25730-7-cristian.marussi@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191007182954.25730-7-cristian.marussi@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191008_110106_572547_FB3A6B05 X-CRM114-Status: GOOD ( 29.26 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: amit.kachhap@arm.com, andreyknvl@google.com, shuah@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 07, 2019 at 07:29:49pm +0100, Cristian Marussi wrote: > Add a simple fake_sigreturn testcase which builds a ucontext_t with a bad > magic header and place it onto the stack. Expects a SIGSEGV on test PASS. > > Introduce a common utility assembly trampoline function to invoke a > sigreturn while placing the provided sigframe at wanted alignment and > also an helper to make space when needed inside the sigframe reserved > area. > > Signed-off-by: Cristian Marussi Looks good to me now: Reviewed-by: Dave Martin Cheers ---Dave > --- > v6 --> v7 > - fix fake_sigreturn alignment routines (+15) > v5 --> v6 > - fake_sigreturn: cleaned up, avoiding excessive SP misalignments > - fake_sigreturn: better formatting and prologue > - get_starting_header: cleand up and commented > - avoid timeout on failure > v3 --> v4 > - fix commit > - fix signal.S, handle misalign requests too > - remove unneeded comments > - add signal.h include > - added get_starting_head() helper > - added test description > --- > tools/testing/selftests/arm64/signal/Makefile | 2 +- > .../testing/selftests/arm64/signal/signals.S | 64 +++++++++++++++++++ > .../arm64/signal/test_signals_utils.h | 2 + > .../testcases/fake_sigreturn_bad_magic.c | 52 +++++++++++++++ > .../arm64/signal/testcases/testcases.c | 46 +++++++++++++ > .../arm64/signal/testcases/testcases.h | 4 ++ > 6 files changed, 169 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/arm64/signal/signals.S > create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c > > diff --git a/tools/testing/selftests/arm64/signal/Makefile b/tools/testing/selftests/arm64/signal/Makefile > index f78f5190e3d4..b497cfea4643 100644 > --- a/tools/testing/selftests/arm64/signal/Makefile > +++ b/tools/testing/selftests/arm64/signal/Makefile > @@ -28,5 +28,5 @@ clean: > # Common test-unit targets to build common-layout test-cases executables > # Needs secondary expansion to properly include the testcase c-file in pre-reqs > .SECONDEXPANSION: > -$(PROGS): test_signals.c test_signals_utils.c testcases/testcases.c $$@.c test_signals.h test_signals_utils.h testcases/testcases.h > +$(PROGS): test_signals.c test_signals_utils.c testcases/testcases.c signals.S $$@.c test_signals.h test_signals_utils.h testcases/testcases.h > $(CC) $(CFLAGS) $^ -o $@ > diff --git a/tools/testing/selftests/arm64/signal/signals.S b/tools/testing/selftests/arm64/signal/signals.S > new file mode 100644 > index 000000000000..9f8c1aefc3b9 > --- /dev/null > +++ b/tools/testing/selftests/arm64/signal/signals.S > @@ -0,0 +1,64 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* Copyright (C) 2019 ARM Limited */ > + > +#include > + > +.section .rodata, "a" > +call_fmt: > + .asciz "Calling sigreturn with fake sigframe sized:%zd at SP @%08lX\n" > + > +.text > + > +.globl fake_sigreturn > + > +/* fake_sigreturn x0:&sigframe, x1:sigframe_size, x2:misalign_bytes */ > +fake_sigreturn: > + stp x29, x30, [sp, #-16]! > + mov x29, sp > + > + mov x20, x0 > + mov x21, x1 > + mov x22, x2 > + > + /* create space on the stack for fake sigframe 16 bytes-aligned */ > + add x0, x21, x22 > + add x0, x0, #15 > + bic x0, x0, #15 /* round_up(sigframe_size + misalign_bytes, 16) */ > + sub sp, sp, x0 > + add x23, sp, x22 /* new sigframe base with misaligment if any */ > + > + ldr x0, =call_fmt > + mov x1, x21 > + mov x2, x23 > + bl printf > + > + /* memcpy the provided content, while still keeping SP aligned */ > + mov x0, x23 > + mov x1, x20 > + mov x2, x21 > + bl memcpy > + > + /* > + * Here saving a last minute SP to current->token acts as a marker: > + * if we got here, we are successfully faking a sigreturn; in other > + * words we are sure no bad fatal signal has been raised till now > + * for unrelated reasons, so we should consider the possibly observed > + * fatal signal like SEGV coming from Kernel restore_sigframe() and > + * triggered as expected from our test-case. > + * For simplicity this assumes that current field 'token' is laid out > + * as first in struct tdescr > + */ > + ldr x0, current > + str x23, [x0] > + /* finally move SP to misaligned address...if any requested */ > + mov sp, x23 > + > + mov x8, #__NR_rt_sigreturn > + svc #0 > + > + /* > + * Above sigreturn should not return...looping here leads to a timeout > + * and ensure proper and clean test failure, instead of jumping around > + * on a potentially corrupted stack. > + */ > + b . > diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.h b/tools/testing/selftests/arm64/signal/test_signals_utils.h > index fd67b1f23c41..6772b5c8d274 100644 > --- a/tools/testing/selftests/arm64/signal/test_signals_utils.h > +++ b/tools/testing/selftests/arm64/signal/test_signals_utils.h > @@ -115,4 +115,6 @@ static __always_inline bool get_current_context(struct tdescr *td, > > return td->live_uc_valid; > } > + > +int fake_sigreturn(void *sigframe, size_t sz, int misalign_bytes); > #endif > diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c > new file mode 100644 > index 000000000000..8dc600a7d4fd > --- /dev/null > +++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c > @@ -0,0 +1,52 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2019 ARM Limited > + * > + * Place a fake sigframe on the stack including a BAD Unknown magic > + * record: on sigreturn Kernel must spot this attempt and the test > + * case is expected to be terminated via SEGV. > + */ > + > +#include > +#include > + > +#include "test_signals_utils.h" > +#include "testcases.h" > + > +struct fake_sigframe sf; > + > +static int fake_sigreturn_bad_magic_run(struct tdescr *td, > + siginfo_t *si, ucontext_t *uc) > +{ > + struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head; > + > + /* just to fill the ucontext_t with something real */ > + if (!get_current_context(td, &sf.uc)) > + return 1; > + > + /* need at least 2*HDR_SZ space: KSFT_BAD_MAGIC + terminator. */ > + head = get_starting_head(shead, HDR_SZ * 2, GET_SF_RESV_SIZE(sf), NULL); > + if (!head) > + return 0; > + > + /* > + * use a well known NON existent bad magic...something > + * we should pretty sure won't be ever defined in Kernel > + */ > + head->magic = KSFT_BAD_MAGIC; > + head->size = HDR_SZ; > + write_terminator_record(GET_RESV_NEXT_HEAD(head)); > + > + ASSERT_BAD_CONTEXT(&sf.uc); > + fake_sigreturn(&sf, sizeof(sf), 0); > + > + return 1; > +} > + > +struct tdescr tde = { > + .name = "FAKE_SIGRETURN_BAD_MAGIC", > + .descr = "Trigger a sigreturn with a sigframe with a bad magic", > + .sig_ok = SIGSEGV, > + .timeout = 3, > + .run = fake_sigreturn_bad_magic_run, > +}; > diff --git a/tools/testing/selftests/arm64/signal/testcases/testcases.c b/tools/testing/selftests/arm64/signal/testcases/testcases.c > index 1914a01222a1..e3521949b800 100644 > --- a/tools/testing/selftests/arm64/signal/testcases/testcases.c > +++ b/tools/testing/selftests/arm64/signal/testcases/testcases.c > @@ -148,3 +148,49 @@ bool validate_reserved(ucontext_t *uc, size_t resv_sz, char **err) > > return true; > } > + > +/* > + * This function walks through the records inside the provided reserved area > + * trying to find enough space to fit @need_sz bytes: if not enough space is > + * available and an extra_context record is present, it throws away the > + * extra_context record. > + * > + * It returns a pointer to a new header where it is possible to start storing > + * our need_sz bytes. > + * > + * @shead: points to the start of reserved area > + * @need_sz: needed bytes > + * @resv_sz: reserved area size in bytes > + * @offset: if not null, this will be filled with the offset of the return > + * head pointer from @shead > + * > + * @return: pointer to a new head where to start storing need_sz bytes, or > + * NULL if space could not be made available. > + */ > +struct _aarch64_ctx *get_starting_head(struct _aarch64_ctx *shead, > + size_t need_sz, size_t resv_sz, > + size_t *offset) > +{ > + size_t offs = 0; > + struct _aarch64_ctx *head; > + > + head = get_terminator(shead, resv_sz, &offs); > + /* not found a terminator...no need to update offset if any */ > + if (!head) > + return head; > + if (resv_sz - offs < need_sz) { > + fprintf(stderr, "Low on space:%zd. Discarding extra_context.\n", > + resv_sz - offs); > + head = get_header(shead, EXTRA_MAGIC, resv_sz, &offs); > + if (!head || resv_sz - offs < need_sz) { > + fprintf(stderr, > + "Failed to reclaim space on sigframe.\n"); > + return NULL; > + } > + } > + > + fprintf(stderr, "Available space:%zd\n", resv_sz - offs); > + if (offset) > + *offset = offs; > + return head; > +} > diff --git a/tools/testing/selftests/arm64/signal/testcases/testcases.h b/tools/testing/selftests/arm64/signal/testcases/testcases.h > index 04987f7870bc..ad884c135314 100644 > --- a/tools/testing/selftests/arm64/signal/testcases/testcases.h > +++ b/tools/testing/selftests/arm64/signal/testcases/testcases.h > @@ -97,4 +97,8 @@ static inline void write_terminator_record(struct _aarch64_ctx *tail) > tail->size = 0; > } > } > + > +struct _aarch64_ctx *get_starting_head(struct _aarch64_ctx *shead, > + size_t need_sz, size_t resv_sz, > + size_t *offset); > #endif > -- > 2.17.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel