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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 56D4AC54FCE for ; Mon, 23 Mar 2020 18:39:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 397B220409 for ; Mon, 23 Mar 2020 18:39:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728073AbgCWSjW (ORCPT ); Mon, 23 Mar 2020 14:39:22 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:46704 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727581AbgCWSiX (ORCPT ); Mon, 23 Mar 2020 14:38:23 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jGRxt-00135W-0G; Mon, 23 Mar 2020 18:38:21 +0000 From: Al Viro To: Linus Torvalds Cc: Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [RFC][PATCH 07/22] x86: get rid of get_user_ex() in restore_sigcontext() Date: Mon, 23 Mar 2020 18:38:04 +0000 Message-Id: <20200323183819.250124-7-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200323183819.250124-1-viro@ZenIV.linux.org.uk> References: <20200323183620.GD23230@ZenIV.linux.org.uk> <20200323183819.250124-1-viro@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Al Viro Just do copyin into a local struct and be done with that - we are on a shallow stack here. [reworked by tglx, removing the macro horrors while we are touching that] Signed-off-by: Al Viro --- arch/x86/kernel/signal.c | 86 ++++++++++++++++++++---------------------------- 1 file changed, 36 insertions(+), 50 deletions(-) diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 53ac66b3fd9b..83563e98f0be 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -47,24 +47,6 @@ #include #include -#define COPY(x) do { \ - get_user_ex(regs->x, &sc->x); \ -} while (0) - -#define GET_SEG(seg) ({ \ - unsigned short tmp; \ - get_user_ex(tmp, &sc->seg); \ - tmp; \ -}) - -#define COPY_SEG(seg) do { \ - regs->seg = GET_SEG(seg); \ -} while (0) - -#define COPY_SEG_CPL3(seg) do { \ - regs->seg = GET_SEG(seg) | 3; \ -} while (0) - #ifdef CONFIG_X86_64 /* * If regs->ss will cause an IRET fault, change it. Otherwise leave it @@ -92,53 +74,58 @@ static void force_valid_ss(struct pt_regs *regs) ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN)) regs->ss = __USER_DS; } +# define CONTEXT_COPY_SIZE offsetof(struct sigcontext, reserved1) +#else +# define CONTEXT_COPY_SIZE sizeof(struct sigcontext) #endif static int restore_sigcontext(struct pt_regs *regs, - struct sigcontext __user *sc, + struct sigcontext __user *usc, unsigned long uc_flags) { - unsigned long buf_val; - void __user *buf; - unsigned int tmpflags; - unsigned int err = 0; + struct sigcontext sc; /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; - get_user_try { + if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE)) + return -EFAULT; #ifdef CONFIG_X86_32 - set_user_gs(regs, GET_SEG(gs)); - COPY_SEG(fs); - COPY_SEG(es); - COPY_SEG(ds); + set_user_gs(regs, sc.gs); + regs->fs = sc.fs; + regs->es = sc.es; + regs->ds = sc.ds; #endif /* CONFIG_X86_32 */ - COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx); - COPY(dx); COPY(cx); COPY(ip); COPY(ax); + regs->bx = sc.bx; + regs->cx = sc.cx; + regs->dx = sc.dx; + regs->si = sc.si; + regs->di = sc.di; + regs->bp = sc.bp; + regs->ax = sc.ax; + regs->sp = sc.sp; + regs->ip = sc.ip; #ifdef CONFIG_X86_64 - COPY(r8); - COPY(r9); - COPY(r10); - COPY(r11); - COPY(r12); - COPY(r13); - COPY(r14); - COPY(r15); + regs->r8 = sc.r8; + regs->r9 = sc.r9; + regs->r10 = sc.r10; + regs->r11 = sc.r11; + regs->r12 = sc.r12; + regs->r13 = sc.r13; + regs->r14 = sc.r14; + regs->r15 = sc.r15; #endif /* CONFIG_X86_64 */ - COPY_SEG_CPL3(cs); - COPY_SEG_CPL3(ss); - - get_user_ex(tmpflags, &sc->flags); - regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS); - regs->orig_ax = -1; /* disable syscall checks */ + /* Get CS/SS and force CPL3 */ + regs->cs = sc.cs | 0x03; + regs->ss = sc.ss | 0x03; - get_user_ex(buf_val, &sc->fpstate); - buf = (void __user *)buf_val; - } get_user_catch(err); + regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS); + /* disable syscall checks */ + regs->orig_ax = -1; #ifdef CONFIG_X86_64 /* @@ -149,9 +136,8 @@ static int restore_sigcontext(struct pt_regs *regs, force_valid_ss(regs); #endif - err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32)); - - return err; + return fpu__restore_sig((void __user *)sc.fpstate, + IS_ENABLED(CONFIG_X86_32)); } int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, -- 2.11.0