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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 6/8] fs, arm64: untag user address in copy_mount_options
Date: Tue,  2 Oct 2018 15:12:41 +0200	[thread overview]
Message-ID: <c16db382982a7c2888e1241a455341118cd63b89.1538485901.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1538485901.git.andreyknvl@google.com>

In copy_mount_options a user address is being subtracted from TASK_SIZE.
If the address is lower than TASK_SIZE, the size is calculated to not
allow the exact_copy_from_user() call to cross TASK_SIZE boundary.
However if the address is tagged, then the size will be calculated
incorrectly.

Untag the address before subtracting.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 fs/namespace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 99186556f8d3..51f763fb9430 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2672,7 +2672,7 @@ void *copy_mount_options(const void __user * data)
 	 * the remainder of the page.
 	 */
 	/* copy_from_user cannot cross TASK_SIZE ! */
-	size = TASK_SIZE - (unsigned long)data;
+	size = TASK_SIZE - (unsigned long)untagged_addr(data);
 	if (size > PAGE_SIZE)
 		size = PAGE_SIZE;
 
-- 
2.19.0.605.g01d371f741-goog

  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 ` [PATCH v7 3/8] arm64: untag user addresses in access_ok and __uaccess_mask_ptr Andrey Konovalov
2018-10-02 13:12   ` 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 ` Andrey Konovalov [this message]
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 ` [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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