From patchwork Wed Feb 16 13:13:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 12748546 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6AE24C433F5 for ; Wed, 16 Feb 2022 13:17:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7E7F76B0083; Wed, 16 Feb 2022 08:17:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 793956B0085; Wed, 16 Feb 2022 08:17:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 596906B0087; Wed, 16 Feb 2022 08:17:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0034.hostedemail.com [216.40.44.34]) by kanga.kvack.org (Postfix) with ESMTP id 445236B0083 for ; Wed, 16 Feb 2022 08:17:56 -0500 (EST) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 03E918249980 for ; Wed, 16 Feb 2022 13:17:56 +0000 (UTC) X-FDA: 79148695752.31.4F4CE56 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf16.hostedemail.com (Postfix) with ESMTP id 6702F180008 for ; Wed, 16 Feb 2022 13:17:55 +0000 (UTC) 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 dfw.source.kernel.org (Postfix) with ESMTPS id BFC62616BD; Wed, 16 Feb 2022 13:17:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3CAEC340F1; Wed, 16 Feb 2022 13:17:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645017474; bh=wEfERj9e8OL/clMCBLXhYlz15Fn6hf3HNftjzVqJD4k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VpXwFdxtIILT0+XPLY+lduLRYuwPqnmC2ynzuDLVFCHjri8xgwCmuVp74WnvIYg+j g8V3zhnC0Zx8cLhfIYomZSb6FlYME/GzEKPVdM1l+QP5ORLR+jeqJxlZAO3BsGBEEb ReiRWWvO8G2nQC5cxE4jgHeBxxTRVMzIx4wmActYFZjJDeaPzJzZY3uNyElEyNTNzW 9M3XRhEDlGZ+cYtfBrNbspvjMaNB8CW9U4Wxd8H2Z1ekinHHymKnJx6CsAxv9dAFlh 5ERdIHNif6ws9hw+oS1Apq2XEN/qAcLDkuJLw+UreQQ4SENteKjPxnvSIdUwAOlScA ODR950gtL1USw== 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, viro@zeniv.linux.org.uk 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-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 v2 13/18] uaccess: generalize access_ok() Date: Wed, 16 Feb 2022 14:13:27 +0100 Message-Id: <20220216131332.1489939-14-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20220216131332.1489939-1-arnd@kernel.org> References: <20220216131332.1489939-1-arnd@kernel.org> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 6702F180008 X-Stat-Signature: 8dnhdpxu56hq79dj3yeqgxqoxr91szpm Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=VpXwFdxt; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf16.hostedemail.com: domain of arnd@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=arnd@kernel.org X-HE-Tag: 1645017475-699631 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: From: Arnd Bergmann There are many different ways that access_ok() is defined across architectures, but in the end, they all just compare against the user_addr_max() value or they accept anything. Provide one definition that works for most architectures, checking against TASK_SIZE_MAX for user processes or skipping the check inside of uaccess_kernel() sections. For architectures without CONFIG_SET_FS(), this should be the fastest check, as it comes down to a single comparison of a pointer against a compile-time constant, while the architecture specific versions tend to do something more complex for historic reasons or get something wrong. Type checking for __user annotations is handled inconsistently across architectures, but this is easily simplified as well by using an inline function that takes a 'const void __user *' argument. A handful of callers need an extra __user annotation for this. Some architectures had trick to use 33-bit or 65-bit arithmetic on the addresses to calculate the overflow, however this simpler version uses fewer registers, which means it can produce better object code in the end despite needing a second (statically predicted) branch. Reviewed-by: Christoph Hellwig Acked-by: Mark Rutland [arm64, asm-generic] Signed-off-by: Arnd Bergmann Acked-by: Geert Uytterhoeven Acked-by: Stafford Horne [openrisc, asm-generic] Acked-by: Dinh Nguyen --- arch/Kconfig | 7 ++++ arch/alpha/include/asm/uaccess.h | 34 +++------------ arch/arc/include/asm/uaccess.h | 29 ------------- arch/arm/include/asm/uaccess.h | 20 +-------- arch/arm64/include/asm/uaccess.h | 11 ++--- arch/csky/include/asm/uaccess.h | 8 ---- arch/hexagon/include/asm/uaccess.h | 25 ------------ arch/ia64/include/asm/uaccess.h | 5 +-- arch/m68k/Kconfig.cpu | 1 + arch/m68k/include/asm/uaccess.h | 19 +-------- arch/microblaze/include/asm/uaccess.h | 8 +--- arch/mips/include/asm/uaccess.h | 29 +------------ arch/nds32/include/asm/uaccess.h | 7 +--- arch/nios2/include/asm/uaccess.h | 11 +---- arch/openrisc/include/asm/uaccess.h | 19 +-------- arch/parisc/Kconfig | 1 + arch/parisc/include/asm/uaccess.h | 12 ++---- arch/powerpc/include/asm/uaccess.h | 11 +---- arch/riscv/include/asm/uaccess.h | 31 +------------- arch/s390/Kconfig | 1 + arch/s390/include/asm/uaccess.h | 14 +------ arch/sh/include/asm/uaccess.h | 22 +--------- arch/sparc/Kconfig | 1 + arch/sparc/include/asm/uaccess.h | 3 -- arch/sparc/include/asm/uaccess_32.h | 18 ++------ arch/sparc/include/asm/uaccess_64.h | 12 +----- arch/um/include/asm/uaccess.h | 5 ++- arch/x86/include/asm/uaccess.h | 14 +------ arch/xtensa/include/asm/uaccess.h | 10 +---- include/asm-generic/access_ok.h | 59 +++++++++++++++++++++++++++ include/asm-generic/uaccess.h | 21 +--------- include/linux/uaccess.h | 7 ---- 32 files changed, 109 insertions(+), 366 deletions(-) create mode 100644 include/asm-generic/access_ok.h diff --git a/arch/Kconfig b/arch/Kconfig index 678a80713b21..fa5db36bda67 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -898,6 +898,13 @@ config HAVE_SOFTIRQ_ON_OWN_STACK Architecture provides a function to run __do_softirq() on a separate stack. +config ALTERNATE_USER_ADDRESS_SPACE + bool + help + Architectures set this when the CPU uses separate address + spaces for kernel and user space pointers. In this case, the + access_ok() check on a __user pointer is skipped. + config PGTABLE_LEVELS int default 2 diff --git a/arch/alpha/include/asm/uaccess.h b/arch/alpha/include/asm/uaccess.h index 1b6f25efa247..82c5743fc9cd 100644 --- a/arch/alpha/include/asm/uaccess.h +++ b/arch/alpha/include/asm/uaccess.h @@ -20,28 +20,7 @@ #define get_fs() (current_thread_info()->addr_limit) #define set_fs(x) (current_thread_info()->addr_limit = (x)) -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) - -/* - * Is a address valid? This does a straightforward calculation rather - * than tests. - * - * Address valid if: - * - "addr" doesn't have any high-bits set - * - AND "size" doesn't have any high-bits set - * - AND "addr+size-(size != 0)" doesn't have any high-bits set - * - OR we are in kernel mode. - */ -#define __access_ok(addr, size) ({ \ - unsigned long __ao_a = (addr), __ao_b = (size); \ - unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b; \ - (get_fs().seg & (__ao_a | __ao_b | __ao_end)) == 0; }) - -#define access_ok(addr, size) \ -({ \ - __chk_user_ptr(addr); \ - __access_ok(((unsigned long)(addr)), (size)); \ -}) +#include /* * These are the main single-value transfer routines. They automatically @@ -105,7 +84,7 @@ extern void __get_user_unknown(void); long __gu_err = -EFAULT; \ unsigned long __gu_val = 0; \ const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ - if (__access_ok((unsigned long)__gu_addr, size)) { \ + if (__access_ok(__gu_addr, size)) { \ __gu_err = 0; \ switch (size) { \ case 1: __get_user_8(__gu_addr); break; \ @@ -200,7 +179,7 @@ extern void __put_user_unknown(void); ({ \ long __pu_err = -EFAULT; \ __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ - if (__access_ok((unsigned long)__pu_addr, size)) { \ + if (__access_ok(__pu_addr, size)) { \ __pu_err = 0; \ switch (size) { \ case 1: __put_user_8(x, __pu_addr); break; \ @@ -316,17 +295,14 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long len) extern long __clear_user(void __user *to, long len); -extern inline long +static inline long clear_user(void __user *to, long len) { - if (__access_ok((unsigned long)to, len)) + if (__access_ok(to, len)) len = __clear_user(to, len); return len; } -#define user_addr_max() \ - (uaccess_kernel() ? ~0UL : TASK_SIZE) - extern long strncpy_from_user(char *dest, const char __user *src, long count); extern __must_check long strnlen_user(const char __user *str, long n); diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h index 783bfdb3bfa3..30f80b4be2ab 100644 --- a/arch/arc/include/asm/uaccess.h +++ b/arch/arc/include/asm/uaccess.h @@ -23,35 +23,6 @@ #include /* for generic string functions */ - -#define __kernel_ok (uaccess_kernel()) - -/* - * Algorithmically, for __user_ok() we want do: - * (start < TASK_SIZE) && (start+len < TASK_SIZE) - * where TASK_SIZE could either be retrieved from thread_info->addr_limit or - * emitted directly in code. - * - * This can however be rewritten as follows: - * (len <= TASK_SIZE) && (start+len < TASK_SIZE) - * - * Because it essentially checks if buffer end is within limit and @len is - * non-ngeative, which implies that buffer start will be within limit too. - * - * The reason for rewriting being, for majority of cases, @len is generally - * compile time constant, causing first sub-expression to be compile time - * subsumed. - * - * The second part would generate weird large LIMMs e.g. (0x6000_0000 - 0x10), - * so we check for TASK_SIZE using get_fs() since the addr_limit load from mem - * would already have been done at this call site for __kernel_ok() - * - */ -#define __user_ok(addr, sz) (((sz) <= TASK_SIZE) && \ - ((addr) <= (get_fs() - (sz)))) -#define __access_ok(addr, sz) (unlikely(__kernel_ok) || \ - likely(__user_ok((addr), (sz)))) - /*********** Single byte/hword/word copies ******************/ #define __get_user_fn(sz, u, k) \ diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index d20d78c34b94..2fcbec9c306c 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -55,21 +55,6 @@ extern int __put_user_bad(void); #ifdef CONFIG_MMU -/* - * We use 33-bit arithmetic here. Success returns zero, failure returns - * addr_limit. We take advantage that addr_limit will be zero for KERNEL_DS, - * so this will always return success in that case. - */ -#define __range_ok(addr, size) ({ \ - unsigned long flag, roksum; \ - __chk_user_ptr(addr); \ - __asm__(".syntax unified\n" \ - "adds %1, %2, %3; sbcscc %1, %1, %0; movcc %0, #0" \ - : "=&r" (flag), "=&r" (roksum) \ - : "r" (addr), "Ir" (size), "0" (TASK_SIZE) \ - : "cc"); \ - flag; }) - /* * This is a type: either unsigned long, if the argument fits into * that type, or otherwise unsigned long long. @@ -241,15 +226,12 @@ extern int __put_user_8(void *, unsigned long long); #else /* CONFIG_MMU */ -#define __addr_ok(addr) ((void)(addr), 1) -#define __range_ok(addr, size) ((void)(addr), 0) - #define get_user(x, p) __get_user(x, p) #define __put_user_check __put_user_nocheck #endif /* CONFIG_MMU */ -#define access_ok(addr, size) (__range_ok(addr, size) == 0) +#include #ifdef CONFIG_CPU_SPECTRE /* diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 199c553b740a..e8dce0cc5eaa 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -26,13 +26,7 @@ #include #include -static inline int __access_ok(const void __user *ptr, unsigned long size) -{ - unsigned long limit = TASK_SIZE_MAX; - unsigned long addr = (unsigned long)ptr; - - return (size <= limit) && (addr <= (limit - size)); -} +static inline int __access_ok(const void __user *ptr, unsigned long size); /* * Test whether a block of memory is a valid user space address. @@ -54,6 +48,9 @@ static inline int access_ok(const void __user *addr, unsigned long size) return likely(__access_ok(addr, size)); } +#define access_ok access_ok + +#include /* * User access enabling/disabling. diff --git a/arch/csky/include/asm/uaccess.h b/arch/csky/include/asm/uaccess.h index ac5a54f57d40..fec8f77ffc99 100644 --- a/arch/csky/include/asm/uaccess.h +++ b/arch/csky/include/asm/uaccess.h @@ -5,14 +5,6 @@ #define user_addr_max() (current_thread_info()->addr_limit.seg) -static inline int __access_ok(unsigned long addr, unsigned long size) -{ - unsigned long limit = user_addr_max(); - - return (size <= limit) && (addr <= (limit - size)); -} -#define __access_ok __access_ok - /* * __put_user_fn */ diff --git a/arch/hexagon/include/asm/uaccess.h b/arch/hexagon/include/asm/uaccess.h index 719ba3f3c45c..bff77efc0d9a 100644 --- a/arch/hexagon/include/asm/uaccess.h +++ b/arch/hexagon/include/asm/uaccess.h @@ -12,31 +12,6 @@ */ #include -/* - * access_ok: - Checks if a user space pointer is valid - * @addr: User space pointer to start of block to check - * @size: Size of block to check - * - * Context: User context only. This function may sleep if pagefaults are - * enabled. - * - * Checks if a pointer to a block of memory in user space is valid. - * - * Returns true (nonzero) if the memory block *may* be valid, false (zero) - * if it is definitely invalid. - * - */ -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) -#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) - -static inline int __access_ok(unsigned long addr, unsigned long size) -{ - unsigned long limit = TASK_SIZE; - - return (size <= limit) && (addr <= (limit - size)); -} -#define __access_ok __access_ok - /* * When a kernel-mode page fault is taken, the faulting instruction * address is checked against a table of exception_table_entries. diff --git a/arch/ia64/include/asm/uaccess.h b/arch/ia64/include/asm/uaccess.h index e19d2dcc0ced..e242a3cc1330 100644 --- a/arch/ia64/include/asm/uaccess.h +++ b/arch/ia64/include/asm/uaccess.h @@ -50,8 +50,6 @@ #define get_fs() (current_thread_info()->addr_limit) #define set_fs(x) (current_thread_info()->addr_limit = (x)) -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) - /* * When accessing user memory, we need to make sure the entire area really is in * user-level space. In order to do this efficiently, we make sure that the page at @@ -65,7 +63,8 @@ static inline int __access_ok(const void __user *p, unsigned long size) return likely(addr <= seg) && (seg == KERNEL_DS.seg || likely(REGION_OFFSET(addr) < RGN_MAP_LIMIT)); } -#define access_ok(addr, size) __access_ok((addr), (size)) +#define __access_ok __access_ok +#include /* * These are the main single-value transfer routines. They automatically diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu index 0d00ef5117dc..16ea9a67723c 100644 --- a/arch/m68k/Kconfig.cpu +++ b/arch/m68k/Kconfig.cpu @@ -453,6 +453,7 @@ config CPU_HAS_NO_UNALIGNED config CPU_HAS_ADDRESS_SPACES bool + select ALTERNATE_USER_ADDRESS_SPACE config FPU bool diff --git a/arch/m68k/include/asm/uaccess.h b/arch/m68k/include/asm/uaccess.h index 8eb625e75452..64914872a5c9 100644 --- a/arch/m68k/include/asm/uaccess.h +++ b/arch/m68k/include/asm/uaccess.h @@ -10,24 +10,7 @@ #include #include #include - -/* We let the MMU do all checking */ -static inline int access_ok(const void __user *ptr, - unsigned long size) -{ - unsigned long limit = TASK_SIZE; - unsigned long addr = (unsigned long)ptr; - - /* - * XXX: for !CONFIG_CPU_HAS_ADDRESS_SPACES this really needs to check - * for TASK_SIZE! - * Removing this helper is probably sufficient. - */ - if (IS_ENABLED(CONFIG_CPU_HAS_ADDRESS_SPACES)) - return 1; - - return (size <= limit) && (addr <= (limit - size)); -} +#include /* * Not all varients of the 68k family support the notion of address spaces. diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h index 3fe96979d2c6..bf9b7657a65a 100644 --- a/arch/microblaze/include/asm/uaccess.h +++ b/arch/microblaze/include/asm/uaccess.h @@ -39,13 +39,7 @@ # define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) -static inline int __access_ok(unsigned long addr, unsigned long size) -{ - unsigned long limit = user_addr_max(); - - return (size <= limit) && (addr <= (limit - size)); -} -#define access_ok(addr, size) __access_ok((unsigned long)addr, size) +#include # define __FIXUP_SECTION ".section .fixup,\"ax\"\n" # define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n" diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h index d7c89dc3426c..436248652b28 100644 --- a/arch/mips/include/asm/uaccess.h +++ b/arch/mips/include/asm/uaccess.h @@ -44,34 +44,7 @@ extern u64 __ua_limit; #endif /* CONFIG_64BIT */ -/* - * access_ok: - Checks if a user space pointer is valid - * @addr: User space pointer to start of block to check - * @size: Size of block to check - * - * Context: User context only. This function may sleep if pagefaults are - * enabled. - * - * Checks if a pointer to a block of memory in user space is valid. - * - * Returns true (nonzero) if the memory block may be valid, false (zero) - * if it is definitely invalid. - * - * Note that, depending on architecture, this function probably just - * checks that the pointer is in the user space range - after calling - * this function, memory access functions may still return -EFAULT. - */ - -static inline int __access_ok(const void __user *p, unsigned long size) -{ - unsigned long addr = (unsigned long)p; - unsigned long limit = TASK_SIZE_MAX; - - return (size <= limit) && (addr <= (limit - size)); -} - -#define access_ok(addr, size) \ - likely(__access_ok((addr), (size))) +#include /* * put_user: - Write a simple value into user space. diff --git a/arch/nds32/include/asm/uaccess.h b/arch/nds32/include/asm/uaccess.h index 37a40981deb3..832d642a4068 100644 --- a/arch/nds32/include/asm/uaccess.h +++ b/arch/nds32/include/asm/uaccess.h @@ -38,18 +38,15 @@ extern int fixup_exception(struct pt_regs *regs); #define get_fs() (current_thread_info()->addr_limit) #define user_addr_max get_fs +#define uaccess_kernel() (get_fs() == KERNEL_DS) static inline void set_fs(mm_segment_t fs) { current_thread_info()->addr_limit = fs; } -#define uaccess_kernel() (get_fs() == KERNEL_DS) +#include -#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs() -size)) - -#define access_ok(addr, size) \ - __range_ok((unsigned long)addr, (unsigned long)size) /* * Single-value transfer routines. They automatically use the right * size if we just have the right pointer type. Note that the functions diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h index a5cbe07cf0da..6664ddc0e8e5 100644 --- a/arch/nios2/include/asm/uaccess.h +++ b/arch/nios2/include/asm/uaccess.h @@ -30,19 +30,10 @@ #define get_fs() (current_thread_info()->addr_limit) #define set_fs(seg) (current_thread_info()->addr_limit = (seg)) -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) - -#define __access_ok(addr, len) \ - (((signed long)(((long)get_fs().seg) & \ - ((long)(addr) | (((long)(addr)) + (len)) | (len)))) == 0) - -#define access_ok(addr, len) \ - likely(__access_ok((unsigned long)(addr), (unsigned long)(len))) +#include # define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n" -#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) - /* * Zero Userspace */ diff --git a/arch/openrisc/include/asm/uaccess.h b/arch/openrisc/include/asm/uaccess.h index 120f5005461b..8f049ec99b3e 100644 --- a/arch/openrisc/include/asm/uaccess.h +++ b/arch/openrisc/include/asm/uaccess.h @@ -45,21 +45,7 @@ #define uaccess_kernel() (get_fs() == KERNEL_DS) -/* Ensure that the range from addr to addr+size is all within the process' - * address space - */ -static inline int __range_ok(unsigned long addr, unsigned long size) -{ - const mm_segment_t fs = get_fs(); - - return size <= fs && addr <= (fs - size); -} - -#define access_ok(addr, size) \ -({ \ - __chk_user_ptr(addr); \ - __range_ok((unsigned long)(addr), (size)); \ -}) +#include /* * These are the main single-value transfer routines. They automatically @@ -268,9 +254,6 @@ clear_user(void __user *addr, unsigned long size) return size; } -#define user_addr_max() \ - (uaccess_kernel() ? ~0UL : TASK_SIZE) - extern long strncpy_from_user(char *dest, const char __user *src, long count); extern __must_check long strnlen_user(const char __user *str, long n); diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 43c1c880def6..15039fdd5413 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 config PARISC def_bool y + select ALTERNATE_USER_ADDRESS_SPACE select ARCH_32BIT_OFF_T if !64BIT select ARCH_MIGHT_HAVE_PC_PARPORT select HAVE_FUNCTION_TRACER diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h index 0925bbd6db67..187f4bdff13e 100644 --- a/arch/parisc/include/asm/uaccess.h +++ b/arch/parisc/include/asm/uaccess.h @@ -11,15 +11,9 @@ #include #include -/* - * Note that since kernel addresses are in a separate address space on - * parisc, we don't need to do anything for access_ok(). - * We just let the page fault handler do the right thing. This also means - * that put_user is the same as __put_user, etc. - */ - -#define access_ok(uaddr, size) \ - ( (uaddr) == (uaddr) ) +#define TASK_SIZE_MAX DEFAULT_TASK_SIZE +#include +#include #define put_user __put_user #define get_user __get_user diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index a0032c2e7550..2e83217f52de 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -11,18 +11,9 @@ #ifdef __powerpc64__ /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */ #define TASK_SIZE_MAX TASK_SIZE_USER64 -#else -#define TASK_SIZE_MAX TASK_SIZE #endif -static inline bool __access_ok(unsigned long addr, unsigned long size) -{ - return addr < TASK_SIZE_MAX && size <= TASK_SIZE_MAX - addr; -} - -#define access_ok(addr, size) \ - (__chk_user_ptr(addr), \ - __access_ok((unsigned long)(addr), (size))) +#include /* * These are the main single-value transfer routines. They automatically diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h index 4407b9e48d2c..855450bed9f5 100644 --- a/arch/riscv/include/asm/uaccess.h +++ b/arch/riscv/include/asm/uaccess.h @@ -21,42 +21,13 @@ #include #include #include +#include #define __enable_user_access() \ __asm__ __volatile__ ("csrs sstatus, %0" : : "r" (SR_SUM) : "memory") #define __disable_user_access() \ __asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory") -/** - * access_ok: - Checks if a user space pointer is valid - * @addr: User space pointer to start of block to check - * @size: Size of block to check - * - * Context: User context only. This function may sleep. - * - * Checks if a pointer to a block of memory in user space is valid. - * - * Returns true (nonzero) if the memory block may be valid, false (zero) - * if it is definitely invalid. - * - * Note that, depending on architecture, this function probably just - * checks that the pointer is in the user space range - after calling - * this function, memory access functions may still return -EFAULT. - */ -#define access_ok(addr, size) ({ \ - __chk_user_ptr(addr); \ - likely(__access_ok((unsigned long __force)(addr), (size))); \ -}) - -/* - * Ensure that the range [addr, addr+size) is within the process's - * address space - */ -static inline int __access_ok(unsigned long addr, unsigned long size) -{ - return size <= TASK_SIZE && addr <= TASK_SIZE - size; -} - /* * The exception table consists of pairs of addresses: the first is the * address of an instruction that is allowed to fault, and the second is diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index be9f39fd06df..fb48a62aa985 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -55,6 +55,7 @@ config S390 # Note: keep this list sorted alphabetically # imply IMA_SECURE_AND_OR_TRUSTED_BOOT + select ALTERNATE_USER_ADDRESS_SPACE select ARCH_32BIT_USTAT_F_TINODE select ARCH_BINFMT_ELF_STATE select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h index 29332edf46f0..5cb258cd9d29 100644 --- a/arch/s390/include/asm/uaccess.h +++ b/arch/s390/include/asm/uaccess.h @@ -17,22 +17,10 @@ #include #include #include +#include void debug_user_asce(int exit); -static inline int __range_ok(unsigned long addr, unsigned long size) -{ - return 1; -} - -#define __access_ok(addr, size) \ -({ \ - __chk_user_ptr(addr); \ - __range_ok((unsigned long)(addr), (size)); \ -}) - -#define access_ok(addr, size) __access_ok(addr, size) - unsigned long __must_check raw_copy_from_user(void *to, const void __user *from, unsigned long n); diff --git a/arch/sh/include/asm/uaccess.h b/arch/sh/include/asm/uaccess.h index 8867bb04b00e..ccd219d74851 100644 --- a/arch/sh/include/asm/uaccess.h +++ b/arch/sh/include/asm/uaccess.h @@ -5,28 +5,10 @@ #include #include -#define __addr_ok(addr) \ - ((unsigned long __force)(addr) < current_thread_info()->addr_limit.seg) - -/* - * __access_ok: Check if address with size is OK or not. - * - * Uhhuh, this needs 33-bit arithmetic. We have a carry.. - * - * sum := addr + size; carry? --> flag = true; - * if (sum >= addr_limit) flag = true; - */ -#define __access_ok(addr, size) ({ \ - unsigned long __ao_a = (addr), __ao_b = (size); \ - unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b; \ - __ao_end >= __ao_a && __addr_ok(__ao_end); }) - -#define access_ok(addr, size) \ - (__chk_user_ptr(addr), \ - __access_ok((unsigned long __force)(addr), (size))) - #define user_addr_max() (current_thread_info()->addr_limit.seg) +#include + /* * Uh, these should become the main single-value transfer routines ... * They automatically use the right size if we just have the right diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 1cab1b284f1a..9f6f9bce5292 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -62,6 +62,7 @@ config SPARC32 config SPARC64 def_bool 64BIT + select ALTERNATE_USER_ADDRESS_SPACE select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_GRAPH_TRACER select HAVE_KRETPROBES diff --git a/arch/sparc/include/asm/uaccess.h b/arch/sparc/include/asm/uaccess.h index 390094200fc4..ee75f69e3fcd 100644 --- a/arch/sparc/include/asm/uaccess.h +++ b/arch/sparc/include/asm/uaccess.h @@ -10,9 +10,6 @@ #include #endif -#define user_addr_max() \ - (uaccess_kernel() ? ~0UL : TASK_SIZE) - long strncpy_from_user(char *dest, const char __user *src, long count); #endif diff --git a/arch/sparc/include/asm/uaccess_32.h b/arch/sparc/include/asm/uaccess_32.h index 4a12346bb69c..367747116260 100644 --- a/arch/sparc/include/asm/uaccess_32.h +++ b/arch/sparc/include/asm/uaccess_32.h @@ -25,17 +25,7 @@ #define get_fs() (current->thread.current_ds) #define set_fs(val) ((current->thread.current_ds) = (val)) -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) - -/* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test - * can be fairly lightweight. - * No one can read/write anything from userland in the kernel space by setting - * large size and address near to PAGE_OFFSET - a fault will break his intentions. - */ -#define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; }) -#define __kernel_ok (uaccess_kernel()) -#define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size))) -#define access_ok(addr, size) __access_ok((unsigned long)(addr), size) +#include /* Uh, these should become the main single-value transfer routines.. * They automatically use the right size if we just have the right @@ -47,13 +37,13 @@ * and hide all the ugliness from the user. */ #define put_user(x, ptr) ({ \ - unsigned long __pu_addr = (unsigned long)(ptr); \ + void __user *__pu_addr = (ptr); \ __chk_user_ptr(ptr); \ __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \ }) #define get_user(x, ptr) ({ \ - unsigned long __gu_addr = (unsigned long)(ptr); \ + const void __user *__gu_addr = (ptr); \ __chk_user_ptr(ptr); \ __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \ }) @@ -232,7 +222,7 @@ static inline unsigned long __clear_user(void __user *addr, unsigned long size) static inline unsigned long clear_user(void __user *addr, unsigned long n) { - if (n && __access_ok((unsigned long) addr, n)) + if (n && __access_ok(addr, n)) return __clear_user(addr, n); else return n; diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h index 5c12fb46bc61..59b9a545df23 100644 --- a/arch/sparc/include/asm/uaccess_64.h +++ b/arch/sparc/include/asm/uaccess_64.h @@ -31,7 +31,7 @@ #define get_fs() ((mm_segment_t){(current_thread_info()->current_ds)}) -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) +#include #define set_fs(val) \ do { \ @@ -61,16 +61,6 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un __chk_range_not_ok((unsigned long __force)(addr), size, limit); \ }) -static inline int __access_ok(const void __user * addr, unsigned long size) -{ - return 1; -} - -static inline int access_ok(const void __user * addr, unsigned long size) -{ - return 1; -} - void __retl_efault(void); /* Uh, these should become the main single-value transfer routines.. diff --git a/arch/um/include/asm/uaccess.h b/arch/um/include/asm/uaccess.h index 1ecfc96bcc50..7d9d60e41e4e 100644 --- a/arch/um/include/asm/uaccess.h +++ b/arch/um/include/asm/uaccess.h @@ -25,7 +25,7 @@ extern unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n); extern unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n); extern unsigned long __clear_user(void __user *mem, unsigned long len); -static inline int __access_ok(unsigned long addr, unsigned long size); +static inline int __access_ok(const void __user *ptr, unsigned long size); /* Teach asm-generic/uaccess.h that we have C functions for these. */ #define __access_ok __access_ok @@ -36,8 +36,9 @@ static inline int __access_ok(unsigned long addr, unsigned long size); #include -static inline int __access_ok(unsigned long addr, unsigned long size) +static inline int __access_ok(const void __user *ptr, unsigned long size) { + unsigned long addr = (unsigned long)ptr; return __addr_range_nowrap(addr, size) && (__under_task_size(addr, size) || __access_ok_vsyscall(addr, size)); diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 201efcec66b7..f78e2b3501a1 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -12,18 +12,6 @@ #include #include -/* - * Test whether a block of memory is a valid user space address. - * Returns 0 if the range is valid, nonzero otherwise. - */ -static inline bool __access_ok(void __user *ptr, unsigned long size) -{ - unsigned long limit = TASK_SIZE_MAX; - unsigned long addr = ptr; - - return (size <= limit) && (addr <= (limit - size)); -} - #ifdef CONFIG_DEBUG_ATOMIC_SLEEP static inline bool pagefault_disabled(void); # define WARN_ON_IN_IRQ() \ @@ -55,6 +43,8 @@ static inline bool pagefault_disabled(void); likely(__access_ok(addr, size)); \ }) +#include + extern int __get_user_1(void); extern int __get_user_2(void); extern int __get_user_4(void); diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h index 75bd8fbf52ba..0edd9e4b23d0 100644 --- a/arch/xtensa/include/asm/uaccess.h +++ b/arch/xtensa/include/asm/uaccess.h @@ -35,15 +35,7 @@ #define get_fs() (current->thread.current_ds) #define set_fs(val) (current->thread.current_ds = (val)) -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) - -#define __kernel_ok (uaccess_kernel()) -#define __user_ok(addr, size) \ - (((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size))) -#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size))) -#define access_ok(addr, size) __access_ok((unsigned long)(addr), (size)) - -#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) +#include /* * These are the main single-value transfer routines. They diff --git a/include/asm-generic/access_ok.h b/include/asm-generic/access_ok.h new file mode 100644 index 000000000000..1aad8964d2ed --- /dev/null +++ b/include/asm-generic/access_ok.h @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_GENERIC_ACCESS_OK_H__ +#define __ASM_GENERIC_ACCESS_OK_H__ + +/* + * Checking whether a pointer is valid for user space access. + * These definitions work on most architectures, but overrides can + * be used where necessary. + */ + +/* + * architectures with compat tasks have a variable TASK_SIZE and should + * override this to a constant. + */ +#ifndef TASK_SIZE_MAX +#define TASK_SIZE_MAX TASK_SIZE +#endif + +#ifndef uaccess_kernel +#ifdef CONFIG_SET_FS +#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) +#else +#define uaccess_kernel() (0) +#endif +#endif + +#ifndef user_addr_max +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE_MAX) +#endif + +#ifndef __access_ok +/* + * 'size' is a compile-time constant for most callers, so optimize for + * this case to turn the check into a single comparison against a constant + * limit and catch all possible overflows. + * On architectures with separate user address space (m68k, s390, parisc, + * sparc64) or those without an MMU, this should always return true. + * + * This version was originally contributed by Jonas Bonn for the + * OpenRISC architecture, and was found to be the most efficient + * for constant 'size' and 'limit' values. + */ +static inline int __access_ok(const void __user *ptr, unsigned long size) +{ + unsigned long limit = user_addr_max(); + unsigned long addr = (unsigned long)ptr; + + if (IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE)) + return true; + + return (size <= limit) && (addr <= (limit - size)); +} +#endif + +#ifndef access_ok +#define access_ok(addr, size) likely(__access_ok(addr, size)) +#endif + +#endif diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index 0870fa11a7c5..ebc685dc8d74 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -114,28 +114,9 @@ static inline void set_fs(mm_segment_t fs) } #endif -#ifndef uaccess_kernel -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) -#endif - -#ifndef user_addr_max -#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) -#endif - #endif /* CONFIG_SET_FS */ -#define access_ok(addr, size) __access_ok((unsigned long)(addr),(size)) - -/* - * The architecture should really override this if possible, at least - * doing a check on the get_fs() - */ -#ifndef __access_ok -static inline int __access_ok(unsigned long addr, unsigned long size) -{ - return 1; -} -#endif +#include /* * These are the main single-value transfer routines. They automatically diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 67e9bc94dc40..2c31667e62e0 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -33,13 +33,6 @@ typedef struct { /* empty dummy */ } mm_segment_t; -#ifndef TASK_SIZE_MAX -#define TASK_SIZE_MAX TASK_SIZE -#endif - -#define uaccess_kernel() (false) -#define user_addr_max() (TASK_SIZE_MAX) - static inline mm_segment_t force_uaccess_begin(void) { return (mm_segment_t) { };