From nobody Tue Feb 10 18:36:34 2026 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 05E6BC7EE2D for ; Thu, 11 May 2023 17:34:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238978AbjEKRey (ORCPT ); Thu, 11 May 2023 13:34:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238964AbjEKRes (ORCPT ); Thu, 11 May 2023 13:34:48 -0400 Received: from mail-lf1-x132.google.com (mail-lf1-x132.google.com [IPv6:2a00:1450:4864:20::132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 896FE59E1 for ; Thu, 11 May 2023 10:34:15 -0700 (PDT) Received: by mail-lf1-x132.google.com with SMTP id 2adb3069b0e04-4f14468ef54so10163355e87.0 for ; Thu, 11 May 2023 10:34:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683826453; x=1686418453; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=3/ujT6jnA5oRzJ9JskN5r6uCjmFXgOFd2DIRefml7o8=; b=LAVNsqv1Aze3d/dQSl9R9cYk9Bbvtr2rGzKHOyJO3d0/M4I5vUi2SMgmXw34JRFjYl AdlAUY1KxPuvHg0vF5szhY3kMSuPgZfSKCe0wsnR7DIKXuYNhDrbQBAlzjAriSa1gFfe 0jrNPA3LPzf/J/WJi/cor3rMn/j2T9b7UhcZI6jhc6uYWskYRSB8o2OFVnbFUSzgAaXm 4n++YCZcveM/k0yWa8YsSvtRzPjFDwUarXs810THzteneZEsQHUz19tRauOr0iUjKpW3 VNwFw7rhMxcMjWongu5AUAkj+H6aX3QazVQZmE4P7+NWeaVl+bza9HflSEplaVi8k40s TZMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683826453; x=1686418453; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=3/ujT6jnA5oRzJ9JskN5r6uCjmFXgOFd2DIRefml7o8=; b=RQ6UvZsNV+YaxE7d/OVOEwvKg/hrbtp57zmKYzDEqBA5QeQ2Wojpzt8dkn/5tuEFTG ajoai9/pfHp3BAfAlOnjZJ+T2U+JdtOqiZPFkPcYQ4rYP7+Km3C6I5RkLvLuwxAVGrIy enoEWS/snGy4igfkcTBOO4e8mD0AG7mrs9LwrW02/xOoQRQlL/jsBR6xtrj/WGNoadWH pvsXreC9BPskwBbVY/QFSWhsd8iF4rpa9szkWr3Wezta16awWbGl/3BClUGDyxCQYmTj kf4Kh2xLbu6wpfdDpf4l2hSg5xJbAVkdnDb8kalJBjiWF+ZWUu3JDd6a43rCtGHbhU4t FeFg== X-Gm-Message-State: AC+VfDwMyxT7vRSsW13ttHnhlutjbRyMyCkF8KDT9ydkiTjzgkDj2bSd si/3dHS4o/ldNIMUyW7mzJOO92I6/XY= X-Google-Smtp-Source: ACHHUZ7/QmhMqp0+mUryx2vQHo4zKlh9dLXgT/+fIm732mC0GMsmc8pBdqVK/AqICLh9b4k04HbF3Q== X-Received: by 2002:a05:6512:963:b0:4f2:4bc2:fc35 with SMTP id v3-20020a056512096300b004f24bc2fc35mr3066181lft.53.1683826452941; Thu, 11 May 2023 10:34:12 -0700 (PDT) Received: from localhost.localdomain ([37.130.110.122]) by smtp.gmail.com with ESMTPSA id a15-20020a056512020f00b004ecad67a925sm1204613lfo.66.2023.05.11.10.34.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 May 2023 10:34:12 -0700 (PDT) From: Max Filippov To: linux-kernel@vger.kernel.org Cc: Chris Zankel , Max Filippov Subject: [PATCH] xtensa: fix signal delivery to FDPIC process Date: Thu, 11 May 2023 10:33:10 -0700 Message-Id: <20230511173310.1757206-1-jcmvbkbc@gmail.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Fetch function descriptor pointed to by the signal handler pointer from userspace on signal delivery and function pointer pointed to by the sa_restorer on return from the signal handler. Fixes: e3ddb8bbe0f8 ("xtensa: add FDPIC and static PIE support for noMMU") Signed-off-by: Max Filippov --- arch/xtensa/kernel/signal.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c index 876d5df157ed..5c01d7e70d90 100644 --- a/arch/xtensa/kernel/signal.c +++ b/arch/xtensa/kernel/signal.c @@ -343,7 +343,19 @@ static int setup_frame(struct ksignal *ksig, sigset_t = *set, struct rt_sigframe *frame; int err =3D 0, sig =3D ksig->sig; unsigned long sp, ra, tp, ps; + unsigned long handler =3D (unsigned long)ksig->ka.sa.sa_handler; + unsigned long handler_fdpic_GOT =3D 0; unsigned int base; + bool fdpic =3D IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) && + (current->personality & FDPIC_FUNCPTRS); + + if (fdpic) { + unsigned long __user *fdpic_func_desc =3D + (unsigned long __user *)handler; + if (__get_user(handler, &fdpic_func_desc[0]) || + __get_user(handler_fdpic_GOT, &fdpic_func_desc[1])) + return -EFAULT; + } =20 sp =3D regs->areg[1]; =20 @@ -373,20 +385,26 @@ static int setup_frame(struct ksignal *ksig, sigset_t= *set, err |=3D __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); =20 if (ksig->ka.sa.sa_flags & SA_RESTORER) { - ra =3D (unsigned long)ksig->ka.sa.sa_restorer; + if (fdpic) { + unsigned long __user *fdpic_func_desc =3D + (unsigned long __user *)ksig->ka.sa.sa_restorer; + + err |=3D __get_user(ra, fdpic_func_desc); + } else { + ra =3D (unsigned long)ksig->ka.sa.sa_restorer; + } } else { =20 /* Create sys_rt_sigreturn syscall in stack frame */ =20 err |=3D gen_return_code(frame->retcode); - - if (err) { - return -EFAULT; - } ra =3D (unsigned long) frame->retcode; } =20 - /*=20 + if (err) + return -EFAULT; + + /* * Create signal handler execution context. * Return context not modified until this point. */ @@ -394,8 +412,7 @@ static int setup_frame(struct ksignal *ksig, sigset_t *= set, /* Set up registers for signal handler; preserve the threadptr */ tp =3D regs->threadptr; ps =3D regs->ps; - start_thread(regs, (unsigned long) ksig->ka.sa.sa_handler, - (unsigned long) frame); + start_thread(regs, handler, (unsigned long)frame); =20 /* Set up a stack frame for a call4 if userspace uses windowed ABI */ if (ps & PS_WOE_MASK) { @@ -413,6 +430,8 @@ static int setup_frame(struct ksignal *ksig, sigset_t *= set, regs->areg[base + 4] =3D (unsigned long) &frame->uc; regs->threadptr =3D tp; regs->ps =3D ps; + if (fdpic) + regs->areg[base + 11] =3D handler_fdpic_GOT; =20 pr_debug("SIG rt deliver (%s:%d): signal=3D%d sp=3D%p pc=3D%08lx\n", current->comm, current->pid, sig, frame, regs->pc); --=20 2.30.2