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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 7F031C43331 for ; Fri, 27 Mar 2020 02:33:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EAF32082D for ; Fri, 27 Mar 2020 02:33:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728035AbgC0CdE (ORCPT ); Thu, 26 Mar 2020 22:33:04 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:48038 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727848AbgC0CcK (ORCPT ); Thu, 26 Mar 2020 22:32:10 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHen0-003hRy-Rw; Fri, 27 Mar 2020 02:32:06 +0000 From: Al Viro To: Linus Torvalds Cc: Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [RFC][PATCH v2 13/22] x86: ia32_setup_sigcontext(): lift user_access_{begin,end}() into the callers Date: Fri, 27 Mar 2020 02:31:56 +0000 Message-Id: <20200327023205.881896-13-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200327023205.881896-1-viro@ZenIV.linux.org.uk> References: <20200327023007.GS23230@ZenIV.linux.org.uk> <20200327023205.881896-1-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 What's left is just a sequence of stores to userland addresses, with all error handling, etc. done out of line. Calling that from user_access block is safe, but rather than teaching objtool to recognize it as such we can just make it always_inline - it is small enough and has few enough callers, for the space savings not to be an issue. Rename the sucker to __unsafe_setup_sigcontext32() and provide unsafe_put_sigcontext32() with usual kind of semantics. Signed-off-by: Al Viro --- arch/x86/ia32/ia32_signal.c | 44 ++++++++++++++++++++++++++++---------------- 1 file changed, 28 insertions(+), 16 deletions(-) diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c index a96995aa23da..799ca5b31b87 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/ia32/ia32_signal.c @@ -154,13 +154,11 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn) #define get_user_seg(seg) ({ unsigned int v; savesegment(seg, v); v; }) -static int ia32_setup_sigcontext(struct sigcontext_32 __user *sc, - void __user *fpstate, - struct pt_regs *regs, unsigned int mask) +static __always_inline int +__unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc, + void __user *fpstate, + struct pt_regs *regs, unsigned int mask) { - if (!user_access_begin(sc, sizeof(struct sigcontext_32))) - return -EFAULT; - unsafe_put_user(get_user_seg(gs), (unsigned int __user *)&sc->gs, Efault); unsafe_put_user(get_user_seg(fs), (unsigned int __user *)&sc->fs, Efault); unsafe_put_user(get_user_seg(ds), (unsigned int __user *)&sc->ds, Efault); @@ -187,13 +185,18 @@ static int ia32_setup_sigcontext(struct sigcontext_32 __user *sc, /* non-iBCS2 extensions.. */ unsafe_put_user(mask, &sc->oldmask, Efault); unsafe_put_user(current->thread.cr2, &sc->cr2, Efault); - user_access_end(); return 0; + Efault: - user_access_end(); return -EFAULT; } +#define unsafe_put_sigcontext32(sc, fp, regs, set, label) \ +do { \ + if (__unsafe_setup_sigcontext32(sc, fp, regs, set->sig[0])) \ + goto label; \ +} while(0) + /* * Determine which stack to use.. */ @@ -234,7 +237,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, struct sigframe_ia32 __user *frame; void __user *restorer; int err = 0; - void __user *fpstate = NULL; + void __user *fp = NULL; /* copy_to_user optimizes that into a single 8 byte store */ static const struct { @@ -247,7 +250,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, 0x80cd, /* int $0x80 */ }; - frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate); + frame = get_sigframe(ksig, regs, sizeof(*frame), &fp); if (!access_ok(frame, sizeof(*frame))) return -EFAULT; @@ -255,9 +258,12 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, if (__put_user(sig, &frame->sig)) return -EFAULT; - if (ia32_setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0])) + if (!user_access_begin(&frame->sc, sizeof(struct sigcontext_32))) return -EFAULT; + unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault); + user_access_end(); + if (__put_user(set->sig[1], &frame->extramask[0])) return -EFAULT; @@ -301,6 +307,9 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, regs->ss = __USER32_DS; return 0; +Efault: + user_access_end(); + return -EFAULT; } int ia32_setup_rt_frame(int sig, struct ksignal *ksig, @@ -309,7 +318,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, struct rt_sigframe_ia32 __user *frame; void __user *restorer; int err = 0; - void __user *fpstate = NULL; + void __user *fp = NULL; /* __copy_to_user optimizes that into a single 8 byte store */ static const struct { @@ -324,7 +333,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, 0, }; - frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate); + frame = get_sigframe(ksig, regs, sizeof(*frame), &fp); if (!user_access_begin(frame, sizeof(*frame))) return -EFAULT; @@ -355,9 +364,12 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault); user_access_end(); - err |= __copy_siginfo_to_user32(&frame->info, &ksig->info, false); - err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate, - regs, set->sig[0]); + if (__copy_siginfo_to_user32(&frame->info, &ksig->info, false)) + return -EFAULT; + if (!user_access_begin(&frame->uc.uc_mcontext, sizeof(struct sigcontext_32))) + return -EFAULT; + unsafe_put_sigcontext32(&frame->uc.uc_mcontext, fp, regs, set, Efault); + user_access_end(); err |= __put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask); if (err) -- 2.11.0