From patchwork Mon Feb 14 16:34:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 12745819 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48930C4332F for ; Mon, 14 Feb 2022 16:37:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356607AbiBNQhe (ORCPT ); Mon, 14 Feb 2022 11:37:34 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:43748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356433AbiBNQhG (ORCPT ); Mon, 14 Feb 2022 11:37:06 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 84E11B85D; Mon, 14 Feb 2022 08:36:45 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id C24B6CE19D9; Mon, 14 Feb 2022 16:36:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6BC36C340EF; Mon, 14 Feb 2022 16:36:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644856602; bh=reX3vVg+fu1kjAfrF+7GPz/swHfDQzZQ+k3OND5IY/w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uHdbggh11BS3osb40rsaIx+cXAkHVb2R0IuywaHPk8G/3hyIBrFrNboxJqken5wPd tuy1saO+tDqDe2v8W9Kr1/Y65+KLtFoiEO1CIQJH7HqQSTRqwZDHIUU87Df0TDMYAh fmpJGSxKQW2ffoxbQW5MEi6rF5DLBeke/TtNycsBXDRAAeIYwg6XaCmWRuaMiY+xCg EkVms+SYJhAhI0w8CnMZNsH4zhsm9cvQ6wjLyFiHRdEvM6xrye5arI+O8NM+hfceJA 1KW7cdAANdnxQ+1Ff9Mi1pkGeTrHHSTQTPe0iKq5znH+H6pJJcAzmWw1/TDhlgeSrb eikdMJEUKLknA== From: Arnd Bergmann To: Linus Torvalds , Christoph Hellwig , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, arnd@arndb.de, linux-kernel@vger.kernel.org Cc: linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, geert@linux-m68k.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, green.hu@gmail.com, dinguyen@kernel.org, shorne@gmail.com, deller@gmx.de, mpe@ellerman.id.au, peterz@infradead.org, mingo@redhat.com, mark.rutland@arm.com, hca@linux.ibm.com, dalias@libc.org, davem@davemloft.net, richard@nod.at, x86@kernel.org, jcmvbkbc@gmail.com, ebiederm@xmission.com, akpm@linux-foundation.org, ardb@kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org Subject: [PATCH 05/14] uaccess: add generic __{get,put}_kernel_nofault Date: Mon, 14 Feb 2022 17:34:43 +0100 Message-Id: <20220214163452.1568807-6-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20220214163452.1568807-1-arnd@kernel.org> References: <20220214163452.1568807-1-arnd@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org From: Arnd Bergmann All architectures that don't provide __{get,put}_kernel_nofault() yet can implement this on top of __{get,put}_user. Add a generic version that lets everything use the normal copy_{from,to}_kernel_nofault() code based on these, removing the last use of get_fs()/set_fs() from architecture-independent code. Signed-off-by: Arnd Bergmann Reviewed-by: Christoph Hellwig --- arch/arm/include/asm/uaccess.h | 2 - arch/arm64/include/asm/uaccess.h | 2 - arch/m68k/include/asm/uaccess.h | 2 - arch/mips/include/asm/uaccess.h | 2 - arch/parisc/include/asm/uaccess.h | 1 - arch/powerpc/include/asm/uaccess.h | 2 - arch/riscv/include/asm/uaccess.h | 2 - arch/s390/include/asm/uaccess.h | 2 - arch/sparc/include/asm/uaccess_64.h | 2 - arch/um/include/asm/uaccess.h | 2 - arch/x86/include/asm/uaccess.h | 2 - include/asm-generic/uaccess.h | 2 - include/linux/uaccess.h | 19 +++++ mm/maccess.c | 108 ---------------------------- 14 files changed, 19 insertions(+), 131 deletions(-) diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 32dbfd81f42a..d20d78c34b94 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -476,8 +476,6 @@ do { \ : "r" (x), "i" (-EFAULT) \ : "cc") -#define HAVE_GET_KERNEL_NOFAULT - #define __get_kernel_nofault(dst, src, type, err_label) \ do { \ const type *__pk_ptr = (src); \ diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 3a5ff5e20586..2e20879fe3cf 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -26,8 +26,6 @@ #include #include -#define HAVE_GET_KERNEL_NOFAULT - /* * Test whether a block of memory is a valid user space address. * Returns 1 if the range is valid, 0 otherwise. diff --git a/arch/m68k/include/asm/uaccess.h b/arch/m68k/include/asm/uaccess.h index ba670523885c..79617c0b2f91 100644 --- a/arch/m68k/include/asm/uaccess.h +++ b/arch/m68k/include/asm/uaccess.h @@ -390,8 +390,6 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n) #define INLINE_COPY_FROM_USER #define INLINE_COPY_TO_USER -#define HAVE_GET_KERNEL_NOFAULT - #define __get_kernel_nofault(dst, src, type, err_label) \ do { \ type *__gk_dst = (type *)(dst); \ diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h index f8f74f9f5883..db9a8e002b62 100644 --- a/arch/mips/include/asm/uaccess.h +++ b/arch/mips/include/asm/uaccess.h @@ -296,8 +296,6 @@ struct __large_struct { unsigned long buf[100]; }; (val) = __gu_tmp.t; \ } -#define HAVE_GET_KERNEL_NOFAULT - #define __get_kernel_nofault(dst, src, type, err_label) \ do { \ int __gu_err; \ diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h index ebf8a845b017..0925bbd6db67 100644 --- a/arch/parisc/include/asm/uaccess.h +++ b/arch/parisc/include/asm/uaccess.h @@ -95,7 +95,6 @@ struct exception_table_entry { (val) = (__force __typeof__(*(ptr))) __gu_val; \ } -#define HAVE_GET_KERNEL_NOFAULT #define __get_kernel_nofault(dst, src, type, err_label) \ { \ type __z; \ diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index 63316100080c..a0032c2e7550 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -467,8 +467,6 @@ do { \ unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \ } while (0) -#define HAVE_GET_KERNEL_NOFAULT - #define __get_kernel_nofault(dst, src, type, err_label) \ __get_user_size_goto(*((type *)(dst)), \ (__force type __user *)(src), sizeof(type), err_label) diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h index c701a5e57a2b..4407b9e48d2c 100644 --- a/arch/riscv/include/asm/uaccess.h +++ b/arch/riscv/include/asm/uaccess.h @@ -346,8 +346,6 @@ unsigned long __must_check clear_user(void __user *to, unsigned long n) __clear_user(to, n) : n; } -#define HAVE_GET_KERNEL_NOFAULT - #define __get_kernel_nofault(dst, src, type, err_label) \ do { \ long __kr_err; \ diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h index d74e26b48604..29332edf46f0 100644 --- a/arch/s390/include/asm/uaccess.h +++ b/arch/s390/include/asm/uaccess.h @@ -282,8 +282,6 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo int copy_to_user_real(void __user *dest, void *src, unsigned long count); void *s390_kernel_write(void *dst, const void *src, size_t size); -#define HAVE_GET_KERNEL_NOFAULT - int __noreturn __put_kernel_bad(void); #define __put_kernel_asm(val, to, insn) \ diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h index b283798315b1..5c12fb46bc61 100644 --- a/arch/sparc/include/asm/uaccess_64.h +++ b/arch/sparc/include/asm/uaccess_64.h @@ -210,8 +210,6 @@ __asm__ __volatile__( \ : "=r" (ret), "=r" (x) : "r" (__m(addr)), \ "i" (-EFAULT)) -#define HAVE_GET_KERNEL_NOFAULT - #define __get_user_nocheck(data, addr, size, type) ({ \ register int __gu_ret; \ register unsigned long __gu_val; \ diff --git a/arch/um/include/asm/uaccess.h b/arch/um/include/asm/uaccess.h index 17d18cfd82a5..1ecfc96bcc50 100644 --- a/arch/um/include/asm/uaccess.h +++ b/arch/um/include/asm/uaccess.h @@ -44,8 +44,6 @@ static inline int __access_ok(unsigned long addr, unsigned long size) } /* no pagefaults for kernel addresses in um */ -#define HAVE_GET_KERNEL_NOFAULT 1 - #define __get_kernel_nofault(dst, src, type, err_label) \ do { \ *((type *)dst) = get_unaligned((type *)(src)); \ diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 6956a63291b6..c6d9dc42724d 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -510,8 +510,6 @@ do { \ unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \ } while (0) -#define HAVE_GET_KERNEL_NOFAULT - #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT #define __get_kernel_nofault(dst, src, type, err_label) \ __get_user_size(*((type *)(dst)), (__force type __user *)(src), \ diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index 10ffa8b5c117..0870fa11a7c5 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -77,8 +77,6 @@ do { \ goto err_label; \ } while (0) -#define HAVE_GET_KERNEL_NOFAULT 1 - static inline __must_check unsigned long raw_copy_from_user(void *to, const void __user * from, unsigned long n) { diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index ac0394087f7d..67e9bc94dc40 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -368,6 +368,25 @@ 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); +#ifndef __get_kernel_nofault +#define __get_kernel_nofault(dst, src, type, label) \ +do { \ + type __user *p = (type __force __user *)(src); \ + type data; \ + if (__get_user(data, p)) \ + goto label; \ + *(type *)dst = data; \ +} while (0) + +#define __put_kernel_nofault(dst, src, type, label) \ +do { \ + type __user *p = (type __force __user *)(dst); \ + type data = *(type *)src; \ + if (__put_user(data, p)) \ + goto label; \ +} while (0) +#endif + /** * get_kernel_nofault(): safely attempt to read from a location * @val: read into this variable diff --git a/mm/maccess.c b/mm/maccess.c index d3f1a1f0b1c1..cbd1b3959af2 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -12,8 +12,6 @@ bool __weak copy_from_kernel_nofault_allowed(const void *unsafe_src, return true; } -#ifdef HAVE_GET_KERNEL_NOFAULT - #define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \ while (len >= sizeof(type)) { \ __get_kernel_nofault(dst, src, type, err_label); \ @@ -102,112 +100,6 @@ long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count) dst[-1] = '\0'; return -EFAULT; } -#else /* HAVE_GET_KERNEL_NOFAULT */ -/** - * copy_from_kernel_nofault(): safely attempt to read from kernel-space - * @dst: pointer to the buffer that shall take the data - * @src: address to read from - * @size: size of the data chunk - * - * Safely read from kernel address @src to the buffer at @dst. If a kernel - * fault happens, handle that and return -EFAULT. If @src is not a valid kernel - * address, return -ERANGE. - * - * We ensure that the copy_from_user is executed in atomic context so that - * do_page_fault() doesn't attempt to take mmap_lock. This makes - * copy_from_kernel_nofault() suitable for use within regions where the caller - * already holds mmap_lock, or other locks which nest inside mmap_lock. - */ -long copy_from_kernel_nofault(void *dst, const void *src, size_t size) -{ - long ret; - mm_segment_t old_fs = get_fs(); - - if (!copy_from_kernel_nofault_allowed(src, size)) - return -ERANGE; - - set_fs(KERNEL_DS); - pagefault_disable(); - ret = __copy_from_user_inatomic(dst, (__force const void __user *)src, - size); - pagefault_enable(); - set_fs(old_fs); - - if (ret) - return -EFAULT; - return 0; -} -EXPORT_SYMBOL_GPL(copy_from_kernel_nofault); - -/** - * copy_to_kernel_nofault(): safely attempt to write to a location - * @dst: address to write to - * @src: pointer to the data that shall be written - * @size: size of the data chunk - * - * Safely write to address @dst from the buffer at @src. If a kernel fault - * happens, handle that and return -EFAULT. - */ -long copy_to_kernel_nofault(void *dst, const void *src, size_t size) -{ - long ret; - mm_segment_t old_fs = get_fs(); - - set_fs(KERNEL_DS); - pagefault_disable(); - ret = __copy_to_user_inatomic((__force void __user *)dst, src, size); - pagefault_enable(); - set_fs(old_fs); - - if (ret) - return -EFAULT; - return 0; -} - -/** - * strncpy_from_kernel_nofault: - Copy a NUL terminated string from unsafe - * address. - * @dst: Destination address, in kernel space. This buffer must be at - * least @count bytes long. - * @unsafe_addr: Unsafe address. - * @count: Maximum number of bytes to copy, including the trailing NUL. - * - * Copies a NUL-terminated string from unsafe address to kernel buffer. - * - * On success, returns the length of the string INCLUDING the trailing NUL. - * - * If access fails, returns -EFAULT (some data may have been copied and the - * trailing NUL added). If @unsafe_addr is not a valid kernel address, return - * -ERANGE. - * - * 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 strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count) -{ - mm_segment_t old_fs = get_fs(); - const void *src = unsafe_addr; - long ret; - - if (unlikely(count <= 0)) - return 0; - if (!copy_from_kernel_nofault_allowed(unsafe_addr, count)) - return -ERANGE; - - set_fs(KERNEL_DS); - pagefault_disable(); - - do { - ret = __get_user(*dst++, (const char __user __force *)src++); - } while (dst[-1] && ret == 0 && src - unsafe_addr < count); - - dst[-1] = '\0'; - pagefault_enable(); - set_fs(old_fs); - - return ret ? -EFAULT : src - unsafe_addr; -} -#endif /* HAVE_GET_KERNEL_NOFAULT */ /** * copy_from_user_nofault(): safely attempt to read from a user-space location