char: hpet: add checks after calling ioremap

The function hpet_resources() calls ioremap() two times, but in both
cases it does not check if ioremap() returned a null pointer. Fix this
by adding null pointer checks and returning an appropriate error.

Signed-off-by: Tom Seewald <tseewald@gmail.com>
Link: https://lore.kernel.org/r/20210503115736.2104747-30-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index 6f13def..8b55085 100644 (file)
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -969,6 +969,8 @@ static acpi_status hpet_resources(struct acpi_resource *res, void *data)
        if (ACPI_SUCCESS(status)) {
                hdp->hd_phys_address = addr.address.minimum;
                hdp->hd_address = ioremap(addr.address.minimum, addr.address.address_length);
+               if (!hdp->hd_address)
+                       return AE_ERROR;
 
                if (hpet_is_known(hdp)) {
                        iounmap(hdp->hd_address);
@@ -982,6 +984,8 @@ static acpi_status hpet_resources(struct acpi_resource *res, void *data)
                hdp->hd_phys_address = fixmem32->address;
                hdp->hd_address = ioremap(fixmem32->address,
                                                HPET_RANGE_SIZE);
+               if (!hdp->hd_address)
+                       return AE_ERROR;
 
                if (hpet_is_known(hdp)) {
                        iounmap(hdp->hd_address);