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[209.85.220.65]) by mx.google.com with SMTPS id y14-v6sor967468wmd.69.2018.06.20.08.24.34 for (Google Transport Security); Wed, 20 Jun 2018 08:24:34 -0700 (PDT) Received-SPF: pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=P4QMe9eU; 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 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=m9bM2usci+57xc3zRMgpKMd80JVfANdAQuqRMxrSXbE=; b=P4QMe9eUNQNmUEDFBBlBegREw9qogy95KBK5zhWridJ7KAYuu4P4qoJ4RSKpU9A9uj 5fca0DIDVpiHr/mfdFgE3ofA/Enl3ijcfpPqVwDoidv/ZBmJd3UfR+UiNCeMZof4XCST 4C/1T1Yp+k36uWBvPwnzfbw0QykFayqOyUY5ncoD2eTJsW/QASmCkGs/GutEvLYzNuJj 869lLy8dgvSAUBlgEVAbePvzExXpPUkKx6xwcWa6d2c6HPYOArGLmbtV9voMXMuXOIDR Yv0PUDda2BBkNvrXOwhUkwNT0fQrGVD3726M/2PMhCspWsSHXdrSHi0Ge+6EaYp8cb5d tjdg== X-Google-Smtp-Source: ADUXVKLQqaSurFJRIyHjy++pghmW5yD8Wq8MdxfPzk2iZvkneLGTJmoAUuaWj2bOKS5adHS07hEvOA== X-Received: by 2002:a1c:9015:: with SMTP id s21-v6mr2104314wmd.20.1529508274166; Wed, 20 Jun 2018 08:24:34 -0700 (PDT) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:84be:a42a:826d:c530]) by smtp.gmail.com with ESMTPSA id c11-v6sm3959244wrm.65.2018.06.20.08.24.32 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Jun 2018 08:24:33 -0700 (PDT) From: Andrey Konovalov To: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Al Viro , Andrey Konovalov , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya Subject: [PATCH v4 3/7] arm64: untag user addresses in access_ok and __uaccess_mask_ptr Date: Wed, 20 Jun 2018 17:24:22 +0200 Message-Id: <69573b1f821c5068be21fdff556cef11f03a09b4.1529507994.git.andreyknvl@google.com> X-Mailer: git-send-email 2.18.0.rc1.244.gcf134e6275-goog In-Reply-To: References: 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: X-Virus-Scanned: ClamAV using ClamSMTP 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, before performing access validity checks. Signed-off-by: Andrey Konovalov --- arch/arm64/include/asm/uaccess.h | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 2d6451cbaa86..fa7318d3d7d5 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) \ @@ -237,7 +238,8 @@ static inline void uaccess_enable_not_uao(void) /* * Sanitise a uaccess pointer such that it becomes NULL if above the - * current addr_limit. + * current addr_limit. In case the pointer is tagged (has the top byte set), + * untag the pointer before checking. */ #define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr) static inline void __user *__uaccess_mask_ptr(const void __user *ptr) @@ -245,10 +247,11 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) void __user *safe_ptr; asm volatile( - " bics xzr, %1, %2\n" + " bics xzr, %3, %2\n" " csel %0, %1, xzr, eq\n" : "=&r" (safe_ptr) - : "r" (ptr), "r" (current_thread_info()->addr_limit) + : "r" (ptr), "r" (current_thread_info()->addr_limit), + "r" (untagged_addr(ptr)) : "cc"); csdb();