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 9EC56C433EF for ; Tue, 19 Jul 2022 13:05:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242974AbiGSNFv (ORCPT ); Tue, 19 Jul 2022 09:05:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243160AbiGSNEr (ORCPT ); Tue, 19 Jul 2022 09:04:47 -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 AE2FC9DEF9; Tue, 19 Jul 2022 05:26:39 -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 22EACB81B10; Tue, 19 Jul 2022 12:26:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58133C341C6; Tue, 19 Jul 2022 12:26:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658233595; bh=eiHQRO2eTKAg/yVdtMzvxSG5jzk8ywMUzDNQLp/ZplQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A0Mw8JjApDAF4JXTvTg4D+aju8NLYWrXNHpipyJluGLeFMTr5dEaS6ZHuTZzPwB2i DTjaDfFCWoEUjTgAJEesx5y4rTTE60hQNApU1fCFVuwnV6pMh/LwZhVg6OeJfZT2Om 4c/4uZPqexYChDuDdtM4zIm3xLv6Tci8t5SIxUV0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Borislav Petkov , Josh Poimboeuf , Sasha Levin Subject: [PATCH 5.18 148/231] objtool: Update Retpoline validation Date: Tue, 19 Jul 2022 13:53:53 +0200 Message-Id: <20220719114726.776451398@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220719114714.247441733@linuxfoundation.org> References: <20220719114714.247441733@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 da251a5645b0..f1a7ecd0a7c7 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 13af6fe453e3..ffaa62167f6e 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 f66e4ac0af94..fbe41203fc9b 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2030,8 +2030,9 @@ 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; } @@ -3561,7 +3562,8 @@ 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) @@ -3576,9 +3578,14 @@ 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