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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 B6A61C433DF for ; Thu, 21 May 2020 15:23:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5A23520829 for ; Thu, 21 May 2020 15:23:49 +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="FSf07PuC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A23520829 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9F12080016; Thu, 21 May 2020 11:23:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 957C48000A; Thu, 21 May 2020 11:23:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7591680016; Thu, 21 May 2020 11:23:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0205.hostedemail.com [216.40.44.205]) by kanga.kvack.org (Postfix) with ESMTP id 524638000A for ; Thu, 21 May 2020 11:23:39 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 1D4504995E7 for ; Thu, 21 May 2020 15:23:39 +0000 (UTC) X-FDA: 76841095758.02.suit35_59f04c8866318 X-HE-Tag: suit35_59f04c8866318 X-Filterd-Recvd-Size: 11259 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Thu, 21 May 2020 15:23:37 +0000 (UTC) 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=ykCHuBjC2MF372WlT5wtfAQHluMa1Im+hWMsa6YO20s=; b=FSf07PuCiBCVvkDyZ2IzN7mjbl 0QvlZG+rOglkCeaghiQ4LHngERt8wdpRQYxRz0h9t9xWKjcg51ZmbBdC2kAj/xkfm/3w3uia2rYlk UK20utLotEH4+rH3l+eNp/14pRNiU/xXbJOWKh9KoEGCY/wxhvRKFyUHL3NbvyAtFfkg/dd+bmEr3 xtSobCTDsFaoCDTIGZe5bUEny9oEKmaujx/py6py5KJcFvSuPT4izUkT/H6ECs3mi4lPIoXZcSE9p WmWRL3UNJokZh4bJ9VEg0W6JcnzpcgmhH2ytZar9uQNXoenSioF7PaKuh/Vwu5UZ7VvMiKWoO5Icb mAS+FR0Q==; Received: from [2001:4bb8:18c:5da7:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jbn2j-0004PA-Ma; Thu, 21 May 2020 15:23:34 +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 10/23] maccess: unify the probe kernel arch hooks Date: Thu, 21 May 2020 17:22:48 +0200 Message-Id: <20200521152301.2587579-11-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200521152301.2587579-1-hch@lst.de> References: <20200521152301.2587579-1-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 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 | 12 ++++------ arch/um/kernel/maccess.c | 10 ++++---- arch/x86/mm/maccess.c | 33 ++++++++++----------------- include/linux/uaccess.h | 6 +++-- mm/maccess.c | 49 ++++++++++++++++++++++++++++++---------- 5 files changed, 61 insertions(+), 49 deletions(-) diff --git a/arch/parisc/lib/memcpy.c b/arch/parisc/lib/memcpy.c index beceaab34ecb7..5b75c35d1da0d 100644 --- a/arch/parisc/lib/memcpy.c +++ b/arch/parisc/lib/memcpy.c @@ -57,14 +57,10 @@ void * memcpy(void * dst,const void *src, size_t coun= t) EXPORT_SYMBOL(raw_copy_in_user); EXPORT_SYMBOL(memcpy); =20 -long probe_kernel_read(void *dst, const void *src, size_t size) +bool probe_kernel_read_allowed(const void *unsafe_src, size_t size, bool= strict) { - unsigned long addr =3D (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..ad2c538ce497c 100644 --- a/arch/um/kernel/maccess.c +++ b/arch/um/kernel/maccess.c @@ -7,15 +7,13 @@ #include #include =20 -long probe_kernel_read(void *dst, const void *src, size_t size) +bool probe_kernel_read_allowed(const void *src, size_t size, bool strict= ) { void *psrc =3D (void *)rounddown((unsigned long)src, PAGE_SIZE); =20 if ((unsigned long)src < PAGE_SIZE || size <=3D 0) - return -EFAULT; - + return false; if (os_mincore(psrc, size + src - psrc) <=3D 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..a96a56ff16109 100644 --- a/arch/x86/mm/maccess.c +++ b/arch/x86/mm/maccess.c @@ -9,35 +9,26 @@ static __always_inline u64 canonical_address(u64 vaddr,= u8 vaddr_bits) return ((s64)vaddr << (64 - vaddr_bits)) >> (64 - vaddr_bits); } =20 -static __always_inline bool invalid_probe_range(u64 vaddr) +bool probe_kernel_read_allowed(const void *unsafe_src, size_t size, bool= strict) { + unsigned long vaddr =3D (unsigned long)unsafe_src; + + if (!strict) + return true; + /* * Range covering the highest possible canonical userspace address * as well as non-canonical address range. For the canonical range * we also need to include the userspace guard page. */ - return vaddr < TASK_SIZE_MAX + PAGE_SIZE || - canonical_address(vaddr, boot_cpu_data.x86_virt_bits) !=3D vaddr= ; + return vaddr >=3D TASK_SIZE_MAX + PAGE_SIZE && + canonical_address(vaddr, boot_cpu_data.x86_virt_bits) =3D=3D vad= dr; } #else -static __always_inline bool invalid_probe_range(u64 vaddr) +bool probe_kernel_read_allowed(const void *unsafe_src, size_t size, bool= strict) { - return vaddr < TASK_SIZE_MAX; + if (!strict) + return true; + return (unsigned long)vaddr >=3D TASK_SIZE_MAX; } #endif - -long probe_kernel_read_strict(void *dst, const void *src, size_t size) -{ - 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, lon= g count) -{ - if (unlikely(invalid_probe_range((unsigned long)unsafe_addr))) - return -EFAULT; - - return __strncpy_from_unsafe(dst, unsafe_addr, count); -} diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index d8366f8468664..65a37ae3b8871 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; } =20 +bool probe_kernel_read_allowed(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 si= ze); =20 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, lo= ng 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..6116742608217 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -6,6 +6,17 @@ #include #include =20 +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(const void *unsafe_src, size_t siz= e, + 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 entirel= y * separate kernel and user address spaces, and also a bad idea otherwis= e. */ -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); =20 /** * 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); +} =20 -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 =3D get_fs(); =20 + if (!probe_kernel_read_allowed(src, size, strict)) + return -EFAULT; + set_fs(KERNEL_DS); pagefault_disable(); ret =3D __copy_from_user_inatomic(dst, (__force const void __user *)src= , @@ -55,7 +75,6 @@ long __probe_kernel_read(void *dst, const void *src, si= ze_t size) return -EFAULT; return 0; } -EXPORT_SYMBOL_GPL(probe_kernel_read); =20 /** * 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 entirel= y * separate kernel and user address spaces, and also a bad idea otherwis= e. */ -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); +} =20 /** * strncpy_from_kernel_nofault: - Copy a NUL terminated string from unsa= fe @@ -182,11 +203,13 @@ long __weak strncpy_from_unsafe(char *dst, const vo= id *unsafe_addr, long count) * If @count is smaller than the length of the string, copies @count-1 b= ytes, * sets the last byte of @dst buffer to NUL and returns @count. */ -long __weak strncpy_from_kernel_nofault(char *dst, const void *unsafe_ad= dr, - long count) - __attribute__((alias("__strncpy_from_unsafe"))); +long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, lon= g count) +{ + return __strncpy_from_unsafe(dst, unsafe_addr, count, true); +} =20 -long __strncpy_from_unsafe(char *dst, const void *unsafe_addr, long coun= t) +static long __strncpy_from_unsafe(char *dst, const void *unsafe_addr, + long count, bool strict) { mm_segment_t old_fs =3D get_fs(); const void *src =3D unsafe_addr; @@ -194,6 +217,8 @@ long __strncpy_from_unsafe(char *dst, const void *uns= afe_addr, long count) =20 if (unlikely(count <=3D 0)) return 0; + if (!probe_kernel_read_allowed(unsafe_addr, count, strict)) + return -EFAULT; =20 set_fs(KERNEL_DS); pagefault_disable(); --=20 2.26.2