From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f199.google.com (mail-wr0-f199.google.com [209.85.128.199]) by kanga.kvack.org (Postfix) with ESMTP id 7DE0D6B0007 for ; Fri, 9 Mar 2018 09:02:18 -0500 (EST) Received: by mail-wr0-f199.google.com with SMTP id u36so5178933wrf.21 for ; Fri, 09 Mar 2018 06:02:18 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id n3sor446167wmn.2.2018.03.09.06.02.17 for (Google Transport Security); Fri, 09 Mar 2018 06:02:17 -0800 (PST) From: Andrey Konovalov Subject: [RFC PATCH 2/6] arm64: untag user addresses in copy_from_user and others Date: Fri, 9 Mar 2018 15:02:00 +0100 Message-Id: In-Reply-To: References: In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Al Viro , Philippe Ombredanne , Greg Kroah-Hartman , Thomas Gleixner , Kate Stewart , Andrew Morton , "Kirill A . Shutemov" , Ingo Molnar , "Aneesh Kumar K . V" , Minchan Kim , Michal Hocko , Shaohua Li , Andrea Arcangeli , Anshuman Khandual , Mike Rapoport , Vlastimil Babka , Naoya Horiguchi , Shakeel Butt , Joonsoo Kim , Hugh Dickins , Mel Gorman , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Mike Kravetz , Zi Yan , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King , Mark Salter , Aurelien Jacquiot , Mikael Starvik , Jesper Nilsson , Tony Luck , Fenghua Yu , Geert Uytterhoeven , James Hogan , Michal Simek , Ralf Baechle , David Howells , Ley Foon Tan , Jonas Bonn , Stefan Kristiansson , Stafford Horne , "James E . J . Bottomley" , Helge Deller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Palmer Dabbelt , Albert Ou , Chen Liqin , Lennox Wu , Yoshinori Sato , Rich Felker , "David S . Miller" , Ingo Molnar , x86@kernel.org, Chris Zankel , Max Filippov , Arnd Bergmann , linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, adi-buildroot-devel@lists.sourceforge.net, linux-c6x-dev@linux-c6x.org, linux-cris-kernel@axis.com, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-metag@vger.kernel.org, linux-mips@linux-mips.org, linux-am33-list@redhat.com, nios2-dev@lists.rocketboards.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Andrey Konovalov copy_from_user (and a few other similar functions) are used to copy data from user memory into the kernel memory or vice versa. Since a user can provided a tagged pointer to one of the syscalls that use copy_from_user, we need to correctly handle such pointers. Do this by untagging user pointers in access_ok and in __uaccess_mask_ptr. Signed-off-by: Andrey Konovalov --- arch/arm64/include/asm/uaccess.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 2d6451cbaa86..24a221678fe3 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -105,7 +105,8 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si #define untagged_addr(addr) \ ((__typeof__(addr))sign_extend64((__u64)(addr), 55)) -#define access_ok(type, addr, size) __range_ok(addr, size) +#define access_ok(type, addr, size) \ + __range_ok(untagged_addr(addr), size) #define user_addr_max get_fs #define _ASM_EXTABLE(from, to) \ @@ -238,12 +239,15 @@ static inline void uaccess_enable_not_uao(void) /* * Sanitise a uaccess pointer such that it becomes NULL if above the * current addr_limit. + * Also untag user pointers that have the top byte tag set. */ #define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr) static inline void __user *__uaccess_mask_ptr(const void __user *ptr) { void __user *safe_ptr; + ptr = untagged_addr(ptr); + asm volatile( " bics xzr, %1, %2\n" " csel %0, %1, xzr, eq\n" -- 2.16.2.395.g2e18187dfd-goog