s390/vmcp: fix uaccess check and avoid undefined behavior

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The vmcp device driver should return -EFAULT if get_user() fails, due
to an invalid user space address. In addition the buffer size value
from user space is passed unchecked to get_order(). The return value
of get_order(0) undefined.

Therefore explicitly test for zero before calling get_order() and also
return -EFAULT if get_user() fails.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

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Heiko Carstens 2017-08-07 15:16:15 +02:00 • committed by Martin Schwidefsky

parent 34ad7cdc1b

commit 267239cc10

1 changed files with 3 additions and 1 deletions

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4

drivers/s390/char/vmcp.c

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