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 485E8C433EF for ; Wed, 20 Jul 2022 01:13:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239190AbiGTBNJ (ORCPT ); Tue, 19 Jul 2022 21:13:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240782AbiGTBM3 (ORCPT ); Tue, 19 Jul 2022 21:12:29 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B39356556B; Tue, 19 Jul 2022 18:12:05 -0700 (PDT) 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 5F571B81DE6; Wed, 20 Jul 2022 01:12:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98CD9C341C6; Wed, 20 Jul 2022 01:12:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1658279523; bh=VoMl3IiXADXOrzYUU30d8G4boCKSZdvtXjRJJHHaY44=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TDcie2KO3OBwvTT5O2M6l0j6f99DtbItqm2N3h8YB/Me2Xcsc4j83RP1GoDGwj2+6 996/g2aEZyU/RDVPXWHAqY/bE1z+B9P7/vTCiL+rBlMw75lgevexKtO9bav68aAxPs uZNh/k32ik3JWvRKKpinpUbo7MYP9Xgp7bvW3pOtqPxOOcFneLyo6ZKsGp7BxM4oGA M7g094X8ECOWxiyfjKXNBtoPwk7dY6j13mbIVBAjBMuGgiy8p37HE9AQnnX36IQhKD oiChHPykcF/xJToKcZxD6+lxZNtJ+h+FQaVg+AIAfAC7Y1cfXLN/RBT/WlYVYrm7WF 9dOlq8GtfsnEw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Peter Zijlstra , Borislav Petkov , Josh Poimboeuf , Sasha Levin , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, luto@kernel.org, jgross@suse.com, pawan.kumar.gupta@linux.intel.com, xen-devel@lists.xenproject.org Subject: [PATCH AUTOSEL 5.18 20/54] objtool: Update Retpoline validation Date: Tue, 19 Jul 2022 21:09:57 -0400 Message-Id: <20220720011031.1023305-20-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220720011031.1023305-1-sashal@kernel.org> References: <20220720011031.1023305-1-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 9bb2ec608a209018080ca262f771e6a9ff203b6f ] Update retpoline validation with the new CONFIG_RETPOLINE requirement of not having bare naked RET instructions. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Signed-off-by: Sasha Levin --- arch/x86/include/asm/nospec-branch.h | 6 ++++++ arch/x86/mm/mem_encrypt_boot.S | 2 ++ arch/x86/xen/xen-head.S | 1 + tools/objtool/check.c | 19 +++++++++++++------ 4 files changed, 22 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 92290b4f1c96..a790109f9337 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -75,6 +75,12 @@ .popsection .endm +/* + * (ab)use RETPOLINE_SAFE on RET to annotate away 'bare' RET instructions + * vs RETBleed validation. + */ +#define ANNOTATE_UNRET_SAFE ANNOTATE_RETPOLINE_SAFE + /* * JMP_NOSPEC and CALL_NOSPEC macros can be used instead of a simple * indirect jmp/call which may be susceptible to the Spectre variant 2 diff --git a/arch/x86/mm/mem_encrypt_boot.S b/arch/x86/mm/mem_encrypt_boot.S index d94dea450fa6..9de3d900bc92 100644 --- a/arch/x86/mm/mem_encrypt_boot.S +++ b/arch/x86/mm/mem_encrypt_boot.S @@ -66,6 +66,7 @@ SYM_FUNC_START(sme_encrypt_execute) pop %rbp /* Offset to __x86_return_thunk would be wrong here */ + ANNOTATE_UNRET_SAFE ret int3 SYM_FUNC_END(sme_encrypt_execute) @@ -154,6 +155,7 @@ SYM_FUNC_START(__enc_copy) pop %r15 /* Offset to __x86_return_thunk would be wrong here */ + ANNOTATE_UNRET_SAFE ret int3 .L__enc_copy_end: diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index 3a2cd93bf059..fa884fc73e07 100644 --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -26,6 +26,7 @@ SYM_CODE_START(hypercall_page) .rept (PAGE_SIZE / 32) UNWIND_HINT_FUNC ANNOTATE_NOENDBR + ANNOTATE_UNRET_SAFE ret /* * Xen will write the hypercall page, and sort out ENDBR. diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 204519704f3b..2daa0dce199b 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2097,8 +2097,9 @@ static int read_retpoline_hints(struct objtool_file *file) } if (insn->type != INSN_JUMP_DYNAMIC && - insn->type != INSN_CALL_DYNAMIC) { - WARN_FUNC("retpoline_safe hint not an indirect jump/call", + insn->type != INSN_CALL_DYNAMIC && + insn->type != INSN_RETURN) { + WARN_FUNC("retpoline_safe hint not an indirect jump/call/ret", insn->sec, insn->offset); return -1; } @@ -3631,7 +3632,8 @@ static int validate_retpoline(struct objtool_file *file) for_each_insn(file, insn) { if (insn->type != INSN_JUMP_DYNAMIC && - insn->type != INSN_CALL_DYNAMIC) + insn->type != INSN_CALL_DYNAMIC && + insn->type != INSN_RETURN) continue; if (insn->retpoline_safe) @@ -3646,9 +3648,14 @@ static int validate_retpoline(struct objtool_file *file) if (!strcmp(insn->sec->name, ".init.text") && !module) continue; - WARN_FUNC("indirect %s found in RETPOLINE build", - insn->sec, insn->offset, - insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call"); + if (insn->type == INSN_RETURN) { + WARN_FUNC("'naked' return found in RETPOLINE build", + insn->sec, insn->offset); + } else { + WARN_FUNC("indirect %s found in RETPOLINE build", + insn->sec, insn->offset, + insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call"); + } warnings++; } -- 2.35.1