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 D1B91C7EE2D for ; Sun, 26 Feb 2023 03:43:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229799AbjBZDnx (ORCPT ); Sat, 25 Feb 2023 22:43:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229696AbjBZDnk (ORCPT ); Sat, 25 Feb 2023 22:43:40 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2AA0B17142; Sat, 25 Feb 2023 19:43:13 -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 ams.source.kernel.org (Postfix) with ESMTPS id 8E075B80B7C; Sun, 26 Feb 2023 03:42:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EB44C433EF; Sun, 26 Feb 2023 03:42:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1677382960; bh=8LArL/D/C43b6ahsO111oIP2+gkAMUgL+RZElVxmw4c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I3xlytzgDlnfUmlRykDJEsjvGEKJZiNROoMEx/yIpG/vZbwLr67iCjk95C7aKC/wD sXySC0prFaFjQEkcgU+HQHTCoxIB1dy/RGmVEkK7d5SLO8aoZe3UK7RkAU71nxqbMl qPO47gIJS5r7e141nlLB7VGLBHZ64LbFg+G6w7lUU/O7WhKM9OHrwG4xNQN6U0v/8c LnyGzdWSvGN1jAz1eDQx3j7PBLSCht6NhwOXevJ1mPBp2VzsMR2PIezn0Ctj0fxwuA lkSaSngTiwGdgXsZM7Uuid074oaV5q0GUTpo2LZamJ0x4ngLifiZ4GeWdCHt6L8FkR WvMlSYvjQyrpQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Tony Lindgren , Ulf Hansson , "Rafael J . Wysocki" , Frederic Weisbecker , Sasha Levin , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, ryabinin.a.a@gmail.com, jpoimboe@kernel.org, keescook@chromium.org, samitolvanen@google.com, kasan-dev@googlegroups.com, linux-mm@kvack.org Subject: [PATCH AUTOSEL 6.2 17/21] entry, kasan, x86: Disallow overriding mem*() functions Date: Sat, 25 Feb 2023 22:41:46 -0500 Message-Id: <20230226034150.771411-17-sashal@kernel.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230226034150.771411-1-sashal@kernel.org> References: <20230226034150.771411-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra [ Upstream commit 69d4c0d3218692ffa56b0e1b9c76c50c699d7044 ] KASAN cannot just hijack the mem*() functions, it needs to emit __asan_mem*() variants if it wants instrumentation (other sanitizers already do this). vmlinux.o: warning: objtool: sync_regs+0x24: call to memcpy() leaves .noinstr.text section vmlinux.o: warning: objtool: vc_switch_off_ist+0xbe: call to memcpy() leaves .noinstr.text section vmlinux.o: warning: objtool: fixup_bad_iret+0x36: call to memset() leaves .noinstr.text section vmlinux.o: warning: objtool: __sev_get_ghcb+0xa0: call to memcpy() leaves .noinstr.text section vmlinux.o: warning: objtool: __sev_put_ghcb+0x35: call to memcpy() leaves .noinstr.text section Remove the weak aliases to ensure nobody hijacks these functions and add them to the noinstr section. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Tested-by: Tony Lindgren Tested-by: Ulf Hansson Acked-by: Rafael J. Wysocki Acked-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20230112195542.028523143@infradead.org Signed-off-by: Sasha Levin --- arch/x86/lib/memcpy_64.S | 5 ++--- arch/x86/lib/memmove_64.S | 4 +++- arch/x86/lib/memset_64.S | 4 +++- mm/kasan/kasan.h | 4 ++++ mm/kasan/shadow.c | 38 ++++++++++++++++++++++++++++++++++++++ tools/objtool/check.c | 3 +++ 6 files changed, 53 insertions(+), 5 deletions(-) diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S index dd8cd8831251f..a64017602010e 100644 --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -8,7 +8,7 @@ #include #include -.pushsection .noinstr.text, "ax" +.section .noinstr.text, "ax" /* * We build a jump to memcpy_orig by default which gets NOPped out on @@ -43,7 +43,7 @@ SYM_TYPED_FUNC_START(__memcpy) SYM_FUNC_END(__memcpy) EXPORT_SYMBOL(__memcpy) -SYM_FUNC_ALIAS_WEAK(memcpy, __memcpy) +SYM_FUNC_ALIAS(memcpy, __memcpy) EXPORT_SYMBOL(memcpy) /* @@ -184,4 +184,3 @@ SYM_FUNC_START_LOCAL(memcpy_orig) RET SYM_FUNC_END(memcpy_orig) -.popsection diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S index 724bbf83eb5b0..02661861e5dd9 100644 --- a/arch/x86/lib/memmove_64.S +++ b/arch/x86/lib/memmove_64.S @@ -13,6 +13,8 @@ #undef memmove +.section .noinstr.text, "ax" + /* * Implement memmove(). This can handle overlap between src and dst. * @@ -213,5 +215,5 @@ SYM_FUNC_START(__memmove) SYM_FUNC_END(__memmove) EXPORT_SYMBOL(__memmove) -SYM_FUNC_ALIAS_WEAK(memmove, __memmove) +SYM_FUNC_ALIAS(memmove, __memmove) EXPORT_SYMBOL(memmove) diff --git a/arch/x86/lib/memset_64.S b/arch/x86/lib/memset_64.S index fc9ffd3ff3b21..6143b1a6fa2ca 100644 --- a/arch/x86/lib/memset_64.S +++ b/arch/x86/lib/memset_64.S @@ -6,6 +6,8 @@ #include #include +.section .noinstr.text, "ax" + /* * ISO C memset - set a memory block to a byte value. This function uses fast * string to get better performance than the original function. The code is @@ -43,7 +45,7 @@ SYM_FUNC_START(__memset) SYM_FUNC_END(__memset) EXPORT_SYMBOL(__memset) -SYM_FUNC_ALIAS_WEAK(memset, __memset) +SYM_FUNC_ALIAS(memset, __memset) EXPORT_SYMBOL(memset) /* diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index ea8cf1310b1e8..71c15438afcfc 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -618,6 +618,10 @@ void __asan_set_shadow_f3(const void *addr, size_t size); void __asan_set_shadow_f5(const void *addr, size_t size); void __asan_set_shadow_f8(const void *addr, size_t size); +void *__asan_memset(void *addr, int c, size_t len); +void *__asan_memmove(void *dest, const void *src, size_t len); +void *__asan_memcpy(void *dest, const void *src, size_t len); + void __hwasan_load1_noabort(unsigned long addr); void __hwasan_store1_noabort(unsigned long addr); void __hwasan_load2_noabort(unsigned long addr); diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c index 15cfb34d16a13..3703983a8e556 100644 --- a/mm/kasan/shadow.c +++ b/mm/kasan/shadow.c @@ -38,6 +38,12 @@ bool __kasan_check_write(const volatile void *p, unsigned int size) } EXPORT_SYMBOL(__kasan_check_write); +#ifndef CONFIG_GENERIC_ENTRY +/* + * CONFIG_GENERIC_ENTRY relies on compiler emitted mem*() calls to not be + * instrumented. KASAN enabled toolchains should emit __asan_mem*() functions + * for the sites they want to instrument. + */ #undef memset void *memset(void *addr, int c, size_t len) { @@ -68,6 +74,38 @@ void *memcpy(void *dest, const void *src, size_t len) return __memcpy(dest, src, len); } +#endif + +void *__asan_memset(void *addr, int c, size_t len) +{ + if (!kasan_check_range((unsigned long)addr, len, true, _RET_IP_)) + return NULL; + + return __memset(addr, c, len); +} +EXPORT_SYMBOL(__asan_memset); + +#ifdef __HAVE_ARCH_MEMMOVE +void *__asan_memmove(void *dest, const void *src, size_t len) +{ + if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) || + !kasan_check_range((unsigned long)dest, len, true, _RET_IP_)) + return NULL; + + return __memmove(dest, src, len); +} +EXPORT_SYMBOL(__asan_memmove); +#endif + +void *__asan_memcpy(void *dest, const void *src, size_t len) +{ + if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) || + !kasan_check_range((unsigned long)dest, len, true, _RET_IP_)) + return NULL; + + return __memcpy(dest, src, len); +} +EXPORT_SYMBOL(__asan_memcpy); void kasan_poison(const void *addr, size_t size, u8 value, bool init) { diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 4b7c8b33069e5..3bd5bbfb4dee0 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1082,6 +1082,9 @@ static const char *uaccess_safe_builtin[] = { "__asan_store16_noabort", "__kasan_check_read", "__kasan_check_write", + "__asan_memset", + "__asan_memmove", + "__asan_memcpy", /* KASAN in-line */ "__asan_report_load_n_noabort", "__asan_report_load1_noabort", -- 2.39.0