From patchwork Tue May 19 13:44:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11557739 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BD4A81391 for ; Tue, 19 May 2020 13:46:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9EF4F20709 for ; Tue, 19 May 2020 13:46:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Da5pMktf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729184AbgESNp3 (ORCPT ); Tue, 19 May 2020 09:45:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729176AbgESNpZ (ORCPT ); Tue, 19 May 2020 09:45:25 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8EBD9C08C5C0; Tue, 19 May 2020 06:45:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=KIuEtIuVTTaP7PWLUSqSXwErp3yBeo2bpzocb9q+81M=; b=Da5pMktffnqSAofQntRtgZWd9j Xzs3vBLJi0BjUMp0iIyR/nav6JRaYJvi2eJFOQ4wsC1d+znjHUDgeeP2I9B46nk4UXBSYDsMf26bR g5Yq2p4vUwZyt6rr0igkwvRl7p9RsOSDiMv0SgPIcDSCpDpy81TIRo8tHWu6wTzg1V/xWxEIfpJqh Nl1kbOPoEV3R7m7RJwbXVViTMxN4YWMkZVxvInXMH60yBkpTXCpzarxRU9JcBX4KQWEdLOgITVrOD Ed1HjAF5EhWbmt6l9JTaPVPEItiChS+hugW7GY9hzFi0mfdLNSOdKgXphNnI7Aht1IM3dugt4OcTy bzb5x+rA==; Received: from [2001:4bb8:188:1506:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jb2Yd-0003fl-Hs; Tue, 19 May 2020 13:45:24 +0000 From: Christoph Hellwig To: x86@kernel.org, Alexei Starovoitov , Daniel Borkmann , Masami Hiramatsu , Linus Torvalds , Andrew Morton Cc: linux-parisc@vger.kernel.org, linux-um@lists.infradead.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 10/20] maccess: unify the probe kernel arch hooks Date: Tue, 19 May 2020 15:44:39 +0200 Message-Id: <20200519134449.1466624-11-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200519134449.1466624-1-hch@lst.de> References: <20200519134449.1466624-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org Currently architectures have to override every routine that probes kernel memory, which includes a pure read and strcpy, both in strict and not strict variants. Just provide a single arch hooks instead to make sure all architectures cover all the cases. Signed-off-by: Christoph Hellwig --- arch/parisc/lib/memcpy.c | 13 ++++------- arch/um/kernel/maccess.c | 11 ++++----- arch/x86/mm/maccess.c | 18 ++++----------- include/linux/uaccess.h | 6 +++-- mm/maccess.c | 49 ++++++++++++++++++++++++++++++---------- 5 files changed, 56 insertions(+), 41 deletions(-) diff --git a/arch/parisc/lib/memcpy.c b/arch/parisc/lib/memcpy.c index beceaab34ecb7..5ef648bd33119 100644 --- a/arch/parisc/lib/memcpy.c +++ b/arch/parisc/lib/memcpy.c @@ -57,14 +57,11 @@ void * memcpy(void * dst,const void *src, size_t count) EXPORT_SYMBOL(raw_copy_in_user); EXPORT_SYMBOL(memcpy); -long probe_kernel_read(void *dst, const void *src, size_t size) +bool probe_kernel_read_allowed(void *dst, const void *unsafe_src, size_t size, + bool strict) { - unsigned long addr = (unsigned long)src; - - if (addr < PAGE_SIZE) - return -EFAULT; - + if ((unsigned long)unsafe_src < PAGE_SIZE) + return false; /* check for I/O space F_EXTEND(0xfff00000) access as well? */ - - return __probe_kernel_read(dst, src, size); + return true; } diff --git a/arch/um/kernel/maccess.c b/arch/um/kernel/maccess.c index 67b2e0fa92bba..90a1bec923158 100644 --- a/arch/um/kernel/maccess.c +++ b/arch/um/kernel/maccess.c @@ -7,15 +7,14 @@ #include #include -long probe_kernel_read(void *dst, const void *src, size_t size) +bool probe_kernel_read_allowed(void *dst, const void *src, size_t size, + bool strict) { void *psrc = (void *)rounddown((unsigned long)src, PAGE_SIZE); if ((unsigned long)src < PAGE_SIZE || size <= 0) - return -EFAULT; - + return false; if (os_mincore(psrc, size + src - psrc) <= 0) - return -EFAULT; - - return __probe_kernel_read(dst, src, size); + return false; + return true; } diff --git a/arch/x86/mm/maccess.c b/arch/x86/mm/maccess.c index 62c4017a2473d..5c323ab187b27 100644 --- a/arch/x86/mm/maccess.c +++ b/arch/x86/mm/maccess.c @@ -26,18 +26,10 @@ static __always_inline bool invalid_probe_range(u64 vaddr) } #endif -long probe_kernel_read_strict(void *dst, const void *src, size_t size) +bool probe_kernel_read_allowed(void *dst, const void *unsafe_src, size_t size, + bool strict) { - if (unlikely(invalid_probe_range((unsigned long)src))) - return -EFAULT; - - return __probe_kernel_read(dst, src, size); -} - -long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count) -{ - if (unlikely(invalid_probe_range((unsigned long)unsafe_addr))) - return -EFAULT; - - return __strncpy_from_unsafe(dst, unsafe_addr, count); + if (!strict) + return true; + return !invalid_probe_range((unsigned long)unsafe_src); } diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index d8366f8468664..7cfc10eb09c60 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -301,9 +301,11 @@ copy_struct_from_user(void *dst, size_t ksize, const void __user *src, return 0; } +bool probe_kernel_read_allowed(void *dst, const void *unsafe_src, + size_t size, bool strict); + extern long probe_kernel_read(void *dst, const void *src, size_t size); extern long probe_kernel_read_strict(void *dst, const void *src, size_t size); -extern long __probe_kernel_read(void *dst, const void *src, size_t size); extern long probe_user_read(void *dst, const void __user *src, size_t size); extern long notrace probe_kernel_write(void *dst, const void *src, size_t size); @@ -312,7 +314,7 @@ extern long notrace probe_user_write(void __user *dst, const void *src, size_t s extern long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count); long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count); -extern long __strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count); + long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr, long count); long strnlen_user_nofault(const void __user *unsafe_addr, long count); diff --git a/mm/maccess.c b/mm/maccess.c index 31cf6604e7fff..483a933b7d241 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -6,6 +6,17 @@ #include #include +static long __probe_kernel_read(void *dst, const void *src, size_t size, + bool strict); +static long __strncpy_from_unsafe(char *dst, const void *unsafe_addr, + long count, bool strict); + +bool __weak probe_kernel_read_allowed(void *dst, const void *unsafe_src, + size_t size, bool strict) +{ + return true; +} + /** * probe_kernel_read(): safely attempt to read from any location * @dst: pointer to the buffer that shall take the data @@ -19,8 +30,11 @@ * DO NOT USE THIS FUNCTION - it is broken on architectures with entirely * separate kernel and user address spaces, and also a bad idea otherwise. */ -long __weak probe_kernel_read(void *dst, const void *src, size_t size) - __attribute__((alias("__probe_kernel_read"))); +long probe_kernel_read(void *dst, const void *src, size_t size) +{ + return __probe_kernel_read(dst, src, size, false); +} +EXPORT_SYMBOL_GPL(probe_kernel_read); /** * probe_kernel_read_strict(): safely attempt to read from kernel-space @@ -36,14 +50,20 @@ long __weak probe_kernel_read(void *dst, const void *src, size_t size) * probe_kernel_read() suitable for use within regions where the caller * already holds mmap_sem, or other locks which nest inside mmap_sem. */ -long __weak probe_kernel_read_strict(void *dst, const void *src, size_t size) - __attribute__((alias("__probe_kernel_read"))); +long probe_kernel_read_strict(void *dst, const void *src, size_t size) +{ + return __probe_kernel_read(dst, src, size, true); +} -long __probe_kernel_read(void *dst, const void *src, size_t size) +static long __probe_kernel_read(void *dst, const void *src, size_t size, + bool strict) { long ret; mm_segment_t old_fs = get_fs(); + if (!probe_kernel_read_allowed(dst, src, size, strict)) + return -EFAULT; + set_fs(KERNEL_DS); pagefault_disable(); ret = __copy_from_user_inatomic(dst, (__force const void __user *)src, @@ -55,7 +75,6 @@ long __probe_kernel_read(void *dst, const void *src, size_t size) return -EFAULT; return 0; } -EXPORT_SYMBOL_GPL(probe_kernel_read); /** * probe_user_read(): safely attempt to read from a user-space location @@ -161,8 +180,10 @@ long probe_user_write(void __user *dst, const void *src, size_t size) * DO NOT USE THIS FUNCTION - it is broken on architectures with entirely * separate kernel and user address spaces, and also a bad idea otherwise. */ -long __weak strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count) - __attribute__((alias("__strncpy_from_unsafe"))); +long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count) +{ + return __strncpy_from_unsafe(dst, unsafe_addr, count, false); +} /** * strncpy_from_kernel_nofault: - Copy a NUL terminated string from unsafe @@ -182,11 +203,13 @@ long __weak strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count) * If @count is smaller than the length of the string, copies @count-1 bytes, * sets the last byte of @dst buffer to NUL and returns @count. */ -long __weak strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, - long count) - __attribute__((alias("__strncpy_from_unsafe"))); +long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count) +{ + return __strncpy_from_unsafe(dst, unsafe_addr, count, true); +} -long __strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count) +static long __strncpy_from_unsafe(char *dst, const void *unsafe_addr, + long count, bool strict) { mm_segment_t old_fs = get_fs(); const void *src = unsafe_addr; @@ -194,6 +217,8 @@ long __strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count) if (unlikely(count <= 0)) return 0; + if (!probe_kernel_read_allowed(dst, unsafe_addr, count, strict)) + return -EFAULT; set_fs(KERNEL_DS); pagefault_disable();