From patchwork Mon Jul 11 20:53:49 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Lutomirski X-Patchwork-Id: 9224177 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5C90860572 for ; Mon, 11 Jul 2016 20:57:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4DE7C27D76 for ; Mon, 11 Jul 2016 20:57:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4296F27E5A; Mon, 11 Jul 2016 20:57:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 6299027D76 for ; Mon, 11 Jul 2016 20:57:09 +0000 (UTC) Received: (qmail 25843 invoked by uid 550); 11 Jul 2016 20:54:51 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: kernel-hardening@lists.openwall.com Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 25662 invoked from network); 11 Jul 2016 20:54:46 -0000 From: Andy Lutomirski To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, Borislav Petkov , Nadav Amit , Kees Cook , Brian Gerst , "kernel-hardening@lists.openwall.com" , Linus Torvalds , Josh Poimboeuf , Jann Horn , Heiko Carstens , Andy Lutomirski Date: Mon, 11 Jul 2016 13:53:49 -0700 Message-Id: <5ceb9aa1bf1ab75af8f9bbde73e93d6d4ce7475f.1468270393.git.luto@kernel.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: X-Virus-Scanned: ClamAV using ClamSMTP Subject: [kernel-hardening] [PATCH v5 16/32] x86: Move uaccess_err and sig_on_uaccess_err to thread_struct X-Virus-Scanned: ClamAV using ClamSMTP thread_info is a legacy mess. To prepare for its partial removal, move the uaccess control fields out -- they're straightforward. Signed-off-by: Andy Lutomirski --- arch/x86/entry/vsyscall/vsyscall_64.c | 6 +++--- arch/x86/include/asm/processor.h | 3 +++ arch/x86/include/asm/thread_info.h | 2 -- arch/x86/include/asm/uaccess.h | 4 ++-- arch/x86/mm/extable.c | 2 +- arch/x86/mm/fault.c | 2 +- 6 files changed, 10 insertions(+), 9 deletions(-) diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c index 174c2549939d..3aba2b043050 100644 --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -221,8 +221,8 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) * With a real vsyscall, page faults cause SIGSEGV. We want to * preserve that behavior to make writing exploits harder. */ - prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error; - current_thread_info()->sig_on_uaccess_error = 1; + prev_sig_on_uaccess_error = current->thread.sig_on_uaccess_error; + current->thread.sig_on_uaccess_error = 1; ret = -EFAULT; switch (vsyscall_nr) { @@ -243,7 +243,7 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) break; } - current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error; + current->thread.sig_on_uaccess_error = prev_sig_on_uaccess_error; check_fault: if (ret == -EFAULT) { diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 62c6cc3cc5d3..f53ae57bd985 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -419,6 +419,9 @@ struct thread_struct { /* Max allowed port in the bitmap, in bytes: */ unsigned io_bitmap_max; + unsigned int sig_on_uaccess_error:1; + unsigned int uaccess_err:1; /* uaccess failed */ + /* Floating point and extended processor state */ struct fpu fpu; /* diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 30c133ac05cd..7c47bb659ecd 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -58,8 +58,6 @@ struct thread_info { __u32 status; /* thread synchronous flags */ __u32 cpu; /* current CPU */ mm_segment_t addr_limit; - unsigned int sig_on_uaccess_error:1; - unsigned int uaccess_err:1; /* uaccess failed */ }; #define INIT_THREAD_INFO(tsk) \ diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 2982387ba817..4d2a726e8e6d 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -468,13 +468,13 @@ struct __large_struct { unsigned long buf[100]; }; * uaccess_try and catch */ #define uaccess_try do { \ - current_thread_info()->uaccess_err = 0; \ + current->thread.uaccess_err = 0; \ __uaccess_begin(); \ barrier(); #define uaccess_catch(err) \ __uaccess_end(); \ - (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0); \ + (err) |= (current->thread.uaccess_err ? -EFAULT : 0); \ } while (0) /** diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 4bb53b89f3c5..0f90cc218d04 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -37,7 +37,7 @@ bool ex_handler_ext(const struct exception_table_entry *fixup, struct pt_regs *regs, int trapnr) { /* Special hack for uaccess_err */ - current_thread_info()->uaccess_err = 1; + current->thread.uaccess_err = 1; regs->ip = ex_fixup_addr(fixup); return true; } diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 76c58fdcfb29..c4c8b4938e93 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -737,7 +737,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, * In this case we need to make sure we're not recursively * faulting through the emulate_vsyscall() logic. */ - if (current_thread_info()->sig_on_uaccess_error && signal) { + if (current->thread.sig_on_uaccess_error && signal) { tsk->thread.trap_nr = X86_TRAP_PF; tsk->thread.error_code = error_code | PF_USER; tsk->thread.cr2 = address;