Messages in this thread | | | Date | Wed, 22 May 2019 13:09:07 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH v15 09/17] fs, arm64: untag user pointers in copy_mount_options |
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On Mon, May 06, 2019 at 06:30:55PM +0200, Andrey Konovalov wrote: > This patch is a part of a series that extends arm64 kernel ABI to allow to > pass tagged user pointers (with the top byte set to something else other > than 0x00) as syscall arguments. > > 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>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
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