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537264f4b3
commit 91428ca932 upstream.
Because of the way the _PAGE_READ is handled in the parisc PTE, an
access interruption is not generated when the kernel reads from a
region where the _PAGE_READ is zero. The current code was written
assuming read access faults would also occur in the kernel.
This change adds user access checks to raw_copy_from_user(). The
prober_user() define checks whether user code has read access to
a virtual address. Note that page faults are not handled in the
exception support for the probe instruction. For this reason, we
precede the probe by a ldb access check.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v5.12+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>