/dev/mem: Avoid overwriting "err" in read_mem()
BugLink: http://bugs.launchpad.net/bugs/1762370
commit
b5b38200ebe54879a7264cb6f33821f61c586a7e upstream.
Successes in probe_kernel_read() would mask failures in copy_to_user()
during read_mem().
Reported-by: Brad Spengler <spender@grsecurity.net>
Fixes: 22ec1a2aea73 ("/dev/mem: Add bounce buffer for copy-out")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>