From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1522169872; cv=none; d=google.com; s=arc-20160816; b=dT3eanY81FgDPWo64hUS/Vg2JEx7DxeKIabZlWl22gjCoOobsboWsLQI3htc+ck6TN fXO6PMjbaIPPJHGGAZ8a4Z1oC3CBYT0ukY1Rf4n6PjDlwzW2P1wqDDV1dNip0kaxbu3k lOARFXqYjIYB43PH9OoGkXUo2jeXRc84C4Dj9LlJs0dfoyUgOlgZAS3Q4nuc0cQFculK +w34OOizzNwghr+cblnCAmpkSilSnJC9qoEGunBC0Hrqxt5ALXsFD3BmjNP7WKNqr/zB 4R6k3O3geB4YA8pZYSJtS20pyR48kEKJIb78n8lYN2m3XBa7TnlN4eIE98Mf7ZXgff3k fHfQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:references:in-reply-to:message-id:date :subject:cc:to:from:dkim-signature:arc-authentication-results; bh=PQDvPwpCCj++tEzmkEClg/xNExzGMoMf+mTY7ONA9sM=; b=qSOc0OH5sN7gMvAZHZbOALBg754qN1bBm3u3cvau3/FhV2ZgBb2KcClE0lbvJkQpuf /ty1Z0U97UzJaToe1olo10Nl12RGe1i1FoK8RMj3D/XSEFoQVT6vzBU/HR3uYtOQ6rZz 4Ol/bLem8MCNtKANt5uobCe+FQSbSBGWM+NknOH85PBrySkc1DZlaw9nsmuc3VeRqwzg FRR/g2vJ1bLYGbNyvYdxnsrA/cjbYCxj/NmfKep1CeQYygLFQkymL3Quj+QLbzSlVDeT W7++dSSTDjWhsLu6TOe7hb9pW6IA5jiaHtfSFlD44x8gLROLM2FDkB3Z6PqsnkNQvww8 2y+g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=ADn0rmiu; spf=pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=andreyknvl@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=ADn0rmiu; spf=pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=andreyknvl@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com X-Google-Smtp-Source: AIpwx4/r7QqaBNv+zh63HY6pUE+6nXfgV70QA44S2r+rRUeb7OeXVCpu+eEC5+uPaXYYZWHThL86gA== From: Andrey Konovalov To: Catalin Marinas , Will Deacon , Jonathan Corbet , Mark Rutland , Robin Murphy , Al Viro , Andrey Konovalov , James Morse , Kees Cook , Bart Van Assche , Kate Stewart , Greg Kroah-Hartman , Thomas Gleixner , Philippe Ombredanne , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Dan Williams , "Aneesh Kumar K . V" , Zi Yan , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan Subject: [RFC PATCH v2 3/6] arm64: untag user addresses in copy_from_user and others Date: Tue, 27 Mar 2018 18:57:39 +0200 Message-Id: <22d41e0e1439ed0d13b2a2ca4b7c8317131f7ea9.1522169685.git.andreyknvl@google.com> X-Mailer: git-send-email 2.17.0.rc0.231.g781580f067-goog In-Reply-To: References: In-Reply-To: References: X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1596110796097198401?= X-GMAIL-MSGID: =?utf-8?q?1596110796097198401?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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" -- 2.17.0.rc0.231.g781580f067-goog