4.20-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
commit 5e9e38d0db1d29efed1dd4cf9a70115d33521be7 upstream.
In preparation for using function number 0 as an error value, prevent it
from being considered a valid function value by acpi_nfit_ctl().
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: stuart hayes <stuart.w.hayes@xxxxxxxxx>
Fixes: e02fb7264d8a ("nfit: add Microsoft NVDIMM DSM command set...")
Reported-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/acpi/nfit/core.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -1844,6 +1844,13 @@ static int acpi_nfit_add_dimm(struct acp
return 0;
}
+ /*
+ * Function 0 is the command interrogation function, don't
+ * export it to potential userspace use, and enable it to be
+ * used as an error value in acpi_nfit_ctl().
+ */
+ dsm_mask &= ~1UL;
+
guid = to_nfit_uuid(nfit_mem->family);
for_each_set_bit(i, &dsm_mask, BITS_PER_LONG)
if (acpi_check_dsm(adev_dimm->handle, guid,
