From patchwork Mon Apr 19 13:07:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 425128 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=-18.8 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=ham 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 59769C43462 for ; Mon, 19 Apr 2021 13:26:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3AE0960FE8 for ; Mon, 19 Apr 2021 13:26:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241913AbhDSN1M (ORCPT ); Mon, 19 Apr 2021 09:27:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:34806 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240998AbhDSN0F (ORCPT ); Mon, 19 Apr 2021 09:26:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 26D38613E2; Mon, 19 Apr 2021 13:21:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618838469; bh=Byr+fhg5Lf5vgurkOuCBRAGK4/82Kv6/CDnJUn53+ek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sKH4XM1u2yJrovzQ+dVybK1PaBT7Rb/++OwLhlp2hfp4+1cvOA3wi9l6Zq7uPaP9s fAiohNU6xI/PzKISzq76tuv3bxjTti4uAPzUQI1cu0SJjIOQdo5MeNNQJw0e176K4R gvaNvMJ86TjWX9FwNHjRNwqCx2klYmSrUOVdV4S8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Fredrik Strupe , Russell King Subject: [PATCH 5.4 72/73] ARM: 9071/1: uprobes: Dont hook on thumb instructions Date: Mon, 19 Apr 2021 15:07:03 +0200 Message-Id: <20210419130526.166823795@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210419130523.802169214@linuxfoundation.org> References: <20210419130523.802169214@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Fredrik Strupe commit d2f7eca60b29006285d57c7035539e33300e89e5 upstream. Since uprobes is not supported for thumb, check that the thumb bit is not set when matching the uprobes instruction hooks. The Arm UDF instructions used for uprobes triggering (UPROBE_SWBP_ARM_INSN and UPROBE_SS_ARM_INSN) coincidentally share the same encoding as a pair of unallocated 32-bit thumb instructions (not UDF) when the condition code is 0b1111 (0xf). This in effect makes it possible to trigger the uprobes functionality from thumb, and at that using two unallocated instructions which are not permanently undefined. Signed-off-by: Fredrik Strupe Cc: stable@vger.kernel.org Fixes: c7edc9e326d5 ("ARM: add uprobes support") Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- arch/arm/probes/uprobes/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/arm/probes/uprobes/core.c +++ b/arch/arm/probes/uprobes/core.c @@ -204,7 +204,7 @@ unsigned long uprobe_get_swbp_addr(struc static struct undef_hook uprobes_arm_break_hook = { .instr_mask = 0x0fffffff, .instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff), - .cpsr_mask = MODE_MASK, + .cpsr_mask = (PSR_T_BIT | MODE_MASK), .cpsr_val = USR_MODE, .fn = uprobe_trap_handler, }; @@ -212,7 +212,7 @@ static struct undef_hook uprobes_arm_bre static struct undef_hook uprobes_arm_ss_hook = { .instr_mask = 0x0fffffff, .instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff), - .cpsr_mask = MODE_MASK, + .cpsr_mask = (PSR_T_BIT | MODE_MASK), .cpsr_val = USR_MODE, .fn = uprobe_trap_handler, };