From patchwork Tue Jul 27 20:58:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 487326 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=-19.5 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=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 82FC0C4338F for ; Tue, 27 Jul 2021 21:00:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BDB060FA0 for ; Tue, 27 Jul 2021 21:00:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232670AbhG0VAx (ORCPT ); Tue, 27 Jul 2021 17:00:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231417AbhG0U7p (ORCPT ); Tue, 27 Jul 2021 16:59:45 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D311C0619D9 for ; Tue, 27 Jul 2021 13:59:13 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id m1so1827911pjv.2 for ; Tue, 27 Jul 2021 13:59:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=TnnuakIxzSbl2ekndF+mmNRk5JCUFYLmPq03TYEYi4k=; b=OPMH+TFnUyOTEkoxkT8a9j8pnksdmlN0EHCCksrBIkm8aOJzAl0mk/zWD1RoSGSmQz C/L9X9iBcobG1ib0rKCDjZAQKbHAE6R5gTbj2TCfQ0bFmmQczYMDgL/RRiTpYgFsbrW8 HIkh5bpT1o12e3mnPAk9NbkSBT/Fxenz2D3aM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=TnnuakIxzSbl2ekndF+mmNRk5JCUFYLmPq03TYEYi4k=; b=fL0GxZrVeNQPHKmhhAmAROa0MgBBkMVrx92FoeWlcHi5b/TpZACEltHPDAMrmc5zOx hE9osgnUFvTsP0D6+75HR8uN035Xs46o9eqoU0S7ito5easWNUjCzwZk9xqHeAek0A8z Rph4kb+PPq8wwueATQBOQrBN1l/97VRBD1F2xtfcZS8KEmHf7oSy7NefJLL0jcNnkn8S Ca8fpwMIrWZgtKLsGUboq7r4ONuQlmCJm9jTPCodajWUlGFpzp8ASfbhGFzquxkAQJq8 xV0RdtTOpZKtuFewZOkM9jKA1auAuH8VoUBl51rdse7/P2oXHtSC675XDfMSVguBntwX shOA== X-Gm-Message-State: AOAM533gE04UH2PUw6Dq7DQb3x3+nO/pXdB641w3RyyWMPsgds2H/Hmg 0O6M5rrP+ZcbewA2iWLMJD8n9g== X-Google-Smtp-Source: ABdhPJxkBBzEoey05rWVspZzYMQI1JMDw2PU6mtY9bM/U5F8n9XWIHWcdKK6WHSgq+klclYhE6H0uQ== X-Received: by 2002:a63:b1b:: with SMTP id 27mr25335957pgl.318.1627419553151; Tue, 27 Jul 2021 13:59:13 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id lt15sm3666524pjb.1.2021.07.27.13.59.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jul 2021 13:59:12 -0700 (PDT) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , "Gustavo A. R. Silva" , Keith Packard , Greg Kroah-Hartman , Andrew Morton , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-staging@lists.linux.dev, linux-block@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com Subject: [PATCH 32/64] fortify: Add compile-time FORTIFY_SOURCE tests Date: Tue, 27 Jul 2021 13:58:23 -0700 Message-Id: <20210727205855.411487-33-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210727205855.411487-1-keescook@chromium.org> References: <20210727205855.411487-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=12511; h=from:subject; bh=Q4J+PNNQ0x2FrnExd2GwHSl8ygCKro8mVNuGZaaMvEE=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBhAHOHi5BjqcFBl+fVaoddPaT/CE3HLMX7Qazay1gP NE/qbu+JAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYQBzhwAKCRCJcvTf3G3AJiyCD/ 9585sT5/jANaceXo2dTbZNeExRTl60qzKyEptgQLDcqJQ/pFIiRSjR2+0L80/dIxqvN5/+ihCjDW7J lCJ6ZsCZXv68CLtTcWBldSTv3eUDI8StzDBDmDQRIWL/5FDUdyvXJWtPZdHNPE10asiv2l1CioXDoa NfhxbbrcVflJPgsM9GpqDGrQHMGANihgjnDGVmBgneVTW68KFFA9dc+ODfnE6zUPCMKiNjug/NMt+j 2GDoP40kDMm6VjUIA6Etvh0hcwV/L/hTOviNjwpvg9b3BibQqis1vPgggUETTlXn2EJQG2/D1SrJ30 5bAqoZ8n8T0ks/jqZXvHezrwBiCeNNoFoBARqEoPfErTigvKiUHaTT4wBMahrHizIRM155dGK/CHA6 h8aUk8QrQSwuaCcsl3nEpQLXQyW61FmXan4g40zpFcplT9dGLj4VGnSlyf13yXSnpxRcSVeSxTBSpq wUXKjf5LXgnkdMI6ru9eQ5DJ7By6AUd9RV69Pvvlym3hu7RafAgWQ0qqse7fG4DGRpBy3pLQI1oOsg Ju7VWB2w35RPMmODBa0sm1rh+eCuJcTk9nRvubxdoneCtG/2x1UVD4TYGBmVA80FM2ncZBrZJH9dWw V+iaOomJvPwMsKIPgbG0fjB3jlcHySCUo55X9f/zVnXGuGS6BPqDRnpXWYGQ== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org While the run-time testing of FORTIFY_SOURCE is already present in LKDTM, there is no testing of the expected compile-time detections. In preparation for correctly supporting FORTIFY_SOURCE under Clang, adding additional FORTIFY_SOURCE defenses, and making sure FORTIFY_SOURCE doesn't silently regress with GCC, introduce a build-time test suite that checks each expected compile-time failure condition. As this is relatively backwards from standard build rules in the sense that a successful test is actually a compile _failure_, create a wrapper script to check for the correct errors, and wire it up as a dummy dependency to lib/string.o, collecting the results into a log file artifact. Signed-off-by: Kees Cook --- lib/.gitignore | 2 + lib/Makefile | 30 ++++++++++ lib/test_fortify/read_overflow-memchr.c | 5 ++ lib/test_fortify/read_overflow-memchr_inv.c | 5 ++ lib/test_fortify/read_overflow-memcmp.c | 5 ++ lib/test_fortify/read_overflow-memscan.c | 5 ++ lib/test_fortify/read_overflow2-memcmp.c | 5 ++ lib/test_fortify/read_overflow2-memcpy.c | 5 ++ lib/test_fortify/read_overflow2-memmove.c | 5 ++ lib/test_fortify/test_fortify.h | 31 ++++++++++ lib/test_fortify/write_overflow-memcpy.c | 5 ++ lib/test_fortify/write_overflow-memmove.c | 5 ++ lib/test_fortify/write_overflow-memset.c | 5 ++ lib/test_fortify/write_overflow-strlcpy.c | 5 ++ lib/test_fortify/write_overflow-strncpy.c | 5 ++ lib/test_fortify/write_overflow-strscpy.c | 5 ++ scripts/test_fortify.sh | 64 +++++++++++++++++++++ 17 files changed, 192 insertions(+) create mode 100644 lib/test_fortify/read_overflow-memchr.c create mode 100644 lib/test_fortify/read_overflow-memchr_inv.c create mode 100644 lib/test_fortify/read_overflow-memcmp.c create mode 100644 lib/test_fortify/read_overflow-memscan.c create mode 100644 lib/test_fortify/read_overflow2-memcmp.c create mode 100644 lib/test_fortify/read_overflow2-memcpy.c create mode 100644 lib/test_fortify/read_overflow2-memmove.c create mode 100644 lib/test_fortify/test_fortify.h create mode 100644 lib/test_fortify/write_overflow-memcpy.c create mode 100644 lib/test_fortify/write_overflow-memmove.c create mode 100644 lib/test_fortify/write_overflow-memset.c create mode 100644 lib/test_fortify/write_overflow-strlcpy.c create mode 100644 lib/test_fortify/write_overflow-strncpy.c create mode 100644 lib/test_fortify/write_overflow-strscpy.c create mode 100644 scripts/test_fortify.sh diff --git a/lib/.gitignore b/lib/.gitignore index 5e7fa54c4536..e5e217b8307b 100644 --- a/lib/.gitignore +++ b/lib/.gitignore @@ -4,3 +4,5 @@ /gen_crc32table /gen_crc64table /oid_registry_data.c +/test_fortify.log +/test_fortify/*.log diff --git a/lib/Makefile b/lib/Makefile index 5efd1b435a37..40b4bf0bc847 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -360,3 +360,33 @@ obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o + +# FORTIFY_SOURCE compile-time behavior tests +TEST_FORTIFY_SRCS = $(wildcard $(srctree)/$(src)/test_fortify/*-*.c) +TEST_FORTIFY_LOGS = $(patsubst $(srctree)/$(src)/%.c, %.log, $(TEST_FORTIFY_SRCS)) +TEST_FORTIFY_LOG = test_fortify.log + +quiet_cmd_test_fortify = TEST $@ + cmd_test_fortify = $(CONFIG_SHELL) $(srctree)/scripts/test_fortify.sh \ + $< $@ "$(NM)" $(CC) $(c_flags) \ + $(call cc-disable-warning,fortify-source) + +targets += $(TEST_FORTIFY_LOGS) +clean-files += $(TEST_FORTIFY_LOGS) +clean-files += $(addsuffix .o, $(TEST_FORTIFY_LOGS)) +$(obj)/test_fortify/%.log: $(src)/test_fortify/%.c $(srctree)/scripts/test_fortify.sh \ + $(srctree)/include/linux/fortify-string.h FORCE + $(call if_changed,test_fortify) + +quiet_cmd_gen_fortify_log = GEN $@ + cmd_gen_fortify_log = cat /dev/null > $@ || true + +targets += $(TEST_FORTIFY_LOG) +clean-files += $(TEST_FORTIFY_LOG) +$(obj)/$(TEST_FORTIFY_LOG): $(addprefix $(obj)/, $(TEST_FORTIFY_LOGS)) FORCE + $(call if_changed,gen_fortify_log) + +# Fake dependency to trigger the fortify tests. +ifeq ($(CONFIG_FORTIFY_SOURCE),y) +$(obj)/string.o: $(obj)/$(TEST_FORTIFY_LOG) +endif diff --git a/lib/test_fortify/read_overflow-memchr.c b/lib/test_fortify/read_overflow-memchr.c new file mode 100644 index 000000000000..2743084b32af --- /dev/null +++ b/lib/test_fortify/read_overflow-memchr.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memchr(small, 0x7A, sizeof(small) + 1) + +#include "test_fortify.h" diff --git a/lib/test_fortify/read_overflow-memchr_inv.c b/lib/test_fortify/read_overflow-memchr_inv.c new file mode 100644 index 000000000000..b26e1f1bc217 --- /dev/null +++ b/lib/test_fortify/read_overflow-memchr_inv.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memchr_inv(small, 0x7A, sizeof(small) + 1) + +#include "test_fortify.h" diff --git a/lib/test_fortify/read_overflow-memcmp.c b/lib/test_fortify/read_overflow-memcmp.c new file mode 100644 index 000000000000..d5d301ff64ef --- /dev/null +++ b/lib/test_fortify/read_overflow-memcmp.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memcmp(small, large, sizeof(small) + 1) + +#include "test_fortify.h" diff --git a/lib/test_fortify/read_overflow-memscan.c b/lib/test_fortify/read_overflow-memscan.c new file mode 100644 index 000000000000..c1a97f2df0f0 --- /dev/null +++ b/lib/test_fortify/read_overflow-memscan.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memscan(small, 0x7A, sizeof(small) + 1) + +#include "test_fortify.h" diff --git a/lib/test_fortify/read_overflow2-memcmp.c b/lib/test_fortify/read_overflow2-memcmp.c new file mode 100644 index 000000000000..c6091e640f76 --- /dev/null +++ b/lib/test_fortify/read_overflow2-memcmp.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memcmp(large, small, sizeof(small) + 1) + +#include "test_fortify.h" diff --git a/lib/test_fortify/read_overflow2-memcpy.c b/lib/test_fortify/read_overflow2-memcpy.c new file mode 100644 index 000000000000..07b62e56cf16 --- /dev/null +++ b/lib/test_fortify/read_overflow2-memcpy.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memcpy(large, instance.buf, sizeof(large)) + +#include "test_fortify.h" diff --git a/lib/test_fortify/read_overflow2-memmove.c b/lib/test_fortify/read_overflow2-memmove.c new file mode 100644 index 000000000000..34edfab040a3 --- /dev/null +++ b/lib/test_fortify/read_overflow2-memmove.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memmove(large, instance.buf, sizeof(large)) + +#include "test_fortify.h" diff --git a/lib/test_fortify/test_fortify.h b/lib/test_fortify/test_fortify.h new file mode 100644 index 000000000000..125f5c585e4f --- /dev/null +++ b/lib/test_fortify/test_fortify.h @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include + +void do_fortify_tests(void); + +# define __BUF_SMALL 16 +# define __BUF_LARGE 32 +struct fortify_object { + int a; + char buf[__BUF_SMALL]; + int c; +}; +const char small_src[__BUF_SMALL] = "AAAAAAAAAAAAAAA"; +const char large_src[__BUF_LARGE] = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"; + +char small[__BUF_SMALL]; +char large[__BUF_LARGE]; +struct fortify_object instance; + +void do_fortify_tests(void) +{ + /* Normal initializations. */ + memset(&instance, 0x32, sizeof(instance)); + memset(small, 0xA5, sizeof(small)); + memset(large, 0x5A, sizeof(large)); + + TEST; +} diff --git a/lib/test_fortify/write_overflow-memcpy.c b/lib/test_fortify/write_overflow-memcpy.c new file mode 100644 index 000000000000..3b3984e428fb --- /dev/null +++ b/lib/test_fortify/write_overflow-memcpy.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memcpy(instance.buf, large_src, sizeof(large_src)) + +#include "test_fortify.h" diff --git a/lib/test_fortify/write_overflow-memmove.c b/lib/test_fortify/write_overflow-memmove.c new file mode 100644 index 000000000000..640437c3b3e0 --- /dev/null +++ b/lib/test_fortify/write_overflow-memmove.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memmove(instance.buf, large_src, sizeof(large_src)) + +#include "test_fortify.h" diff --git a/lib/test_fortify/write_overflow-memset.c b/lib/test_fortify/write_overflow-memset.c new file mode 100644 index 000000000000..36e34908cfb3 --- /dev/null +++ b/lib/test_fortify/write_overflow-memset.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + memset(instance.buf, 0x5A, sizeof(large_src)) + +#include "test_fortify.h" diff --git a/lib/test_fortify/write_overflow-strlcpy.c b/lib/test_fortify/write_overflow-strlcpy.c new file mode 100644 index 000000000000..1883db7c0cd6 --- /dev/null +++ b/lib/test_fortify/write_overflow-strlcpy.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + strlcpy(instance.buf, large_src, sizeof(instance.buf) + 1) + +#include "test_fortify.h" diff --git a/lib/test_fortify/write_overflow-strncpy.c b/lib/test_fortify/write_overflow-strncpy.c new file mode 100644 index 000000000000..b85f079c815d --- /dev/null +++ b/lib/test_fortify/write_overflow-strncpy.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + strncpy(instance.buf, large_src, sizeof(instance.buf) + 1) + +#include "test_fortify.h" diff --git a/lib/test_fortify/write_overflow-strscpy.c b/lib/test_fortify/write_overflow-strscpy.c new file mode 100644 index 000000000000..38feddf377dc --- /dev/null +++ b/lib/test_fortify/write_overflow-strscpy.c @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define TEST \ + strscpy(instance.buf, large_src, sizeof(instance.buf) + 1) + +#include "test_fortify.h" diff --git a/scripts/test_fortify.sh b/scripts/test_fortify.sh new file mode 100644 index 000000000000..59b362eed2ac --- /dev/null +++ b/scripts/test_fortify.sh @@ -0,0 +1,64 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only +set -e + +# Argument 1: Source file to build. +IN="$1" +shift +# Extract just the filename for error messages below. +FILE="${IN##*/}" +# Extract the function name for error messages below. +FUNC="${FILE##*-}" +FUNC="${FUNC%%.*}" +# Extract the symbol to test for in build/symbol test below. +WANT="__${FILE%%-*}" + +# Argument 2: Where to write the build log. +OUT="$1" +shift +TMP="${OUT}.tmp" + +# Argument 3: Path to "nm" tool. +NM="$1" +shift + +# Remaining arguments are: $(CC) $(c_flags) + +# Skip this test, it is currently failing on all compilers. +if [ "$WANT $FUNC" = "__write_overflow strlcpy" ] ; then + echo "skip: unsafe ${FUNC}() usage not checked for '$WANT' in $IN" > "$OUT" + exit 0 +fi + +# Clean up temporary file at exit. +__cleanup() { + rm -f "$TMP" +} +trap __cleanup EXIT + +status= +# Attempt to build a source that is expected to fail with a specific warning. +if "$@" -Werror -c "$IN" -o "$OUT".o 2> "$TMP" ; then + # If the build succeeds, either the test has failed or the the + # warning may only happen at link time (Clang). In that case, + # make sure the expected symbol is unresolved in the symbol list. + # If so, FORTIFY is working for this case. + if ! $NM -A "$OUT".o | grep -m1 "\bU ${WANT}$" >>"$TMP" ; then + status="warning: unsafe ${FUNC}() usage lacked '$WANT' symbol in $IN" + fi +else + # If the build failed, check for the warning in the stderr (gcc). + if ! grep -q -m1 "error:.*\b${WANT}'" "$TMP" ; then + status="warning: unsafe ${FUNC}() usage lacked '$WANT' warning in $IN" + fi +fi + +if [ -n "$status" ]; then + # Report on failure results, including compilation warnings. + echo "$status" | tee "$OUT" >&2 + cat "$TMP" | tee -a "$OUT" >&2 +else + # Report on good results, and save any compilation output to log. + echo "ok: unsafe ${FUNC}() usage correctly detected with '$WANT' in $IN" >"$OUT" + cat "$TMP" >>"$OUT" +fi