From: Andrey Konovalov <andreyknvl@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Kees Cook <keescook@chromium.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Shuah Khan <shuah@kernel.org>,
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 <dvyukov@google.com>,
Kostya Serebryany <kcc@google.com>,
Evgeniy Stepanov <eugenis@google.com>,
Lee Smith <Lee.Smith@arm.com>,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
Jacob Bramley <Jacob.Bramley@arm.com>,
Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
Chintan Pandya <cpandya@codeaurora.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v7 3/8] arm64: untag user addresses in access_ok and __uaccess_mask_ptr
Date: Tue, 2 Oct 2018 15:12:38 +0200 [thread overview]
Message-ID: <2b957e4f0a3133480dda9d9c8aeceb9b9d9378eb.1538485901.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1538485901.git.andreyknvl@google.com>
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 <andreyknvl@google.com>
---
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();
--
2.19.0.605.g01d371f741-goog
next prev parent reply other threads:[~2018-10-02 13:12 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-02 13:12 [PATCH v7 0/8] arm64: untag user pointers passed to the kernel Andrey Konovalov
2018-10-02 13:12 ` Andrey Konovalov
2018-10-02 13:12 ` [PATCH v7 1/8] arm64: add type casts to untagged_addr macro Andrey Konovalov
2018-10-02 13:12 ` Andrey Konovalov
2018-10-02 13:12 ` [PATCH v7 2/8] uaccess: add untagged_addr definition for other arches Andrey Konovalov
2018-10-02 13:12 ` Andrey Konovalov
2018-10-02 13:12 ` Andrey Konovalov [this message]
2018-10-02 13:12 ` [PATCH v7 3/8] arm64: untag user addresses in access_ok and __uaccess_mask_ptr Andrey Konovalov
2018-10-02 13:12 ` [PATCH v7 4/8] mm, arm64: untag user addresses in mm/gup.c Andrey Konovalov
2018-10-02 13:12 ` Andrey Konovalov
2018-10-02 13:12 ` [PATCH v7 5/8] lib, arm64: untag addrs passed to strncpy_from_user and strnlen_user Andrey Konovalov
2018-10-02 13:12 ` Andrey Konovalov
2018-10-02 13:12 ` [PATCH v7 6/8] fs, arm64: untag user address in copy_mount_options Andrey Konovalov
2018-10-02 13:12 ` Andrey Konovalov
2018-10-02 13:12 ` [PATCH v7 7/8] arm64: update Documentation/arm64/tagged-pointers.txt Andrey Konovalov
2018-10-02 13:12 ` Andrey Konovalov
2018-10-03 17:32 ` Catalin Marinas
2018-10-03 17:32 ` Catalin Marinas
2018-10-10 14:09 ` Andrey Konovalov
2018-10-10 14:09 ` Andrey Konovalov
2018-10-18 17:31 ` Catalin Marinas
2018-10-18 17:31 ` Catalin Marinas
2018-10-02 13:12 ` [PATCH v7 8/8] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2018-10-02 13:12 ` Andrey Konovalov
2018-10-03 13:31 ` [PATCH v7 0/8] arm64: untag user pointers passed to the kernel Luc Van Oostenryck
2018-10-03 13:31 ` Luc Van Oostenryck
2018-10-17 14:06 ` Vincenzo Frascino
2018-10-17 14:06 ` Vincenzo Frascino
2018-10-17 14:20 ` Andrey Konovalov
2018-10-17 14:20 ` Andrey Konovalov
2018-10-17 20:25 ` Evgenii Stepanov
2018-10-17 20:25 ` Evgenii Stepanov
2018-10-18 17:33 ` Catalin Marinas
2018-10-18 17:33 ` Catalin Marinas
2018-10-19 9:04 ` Vincenzo Frascino
2018-10-19 9:04 ` Vincenzo Frascino
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