From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date: Tue, 22 Mar 2022 16:02:05 +0000 (+0100)
Subject: ACPI: CPPC: Avoid out of bounds access when parsing _CPC data
X-Git-Tag: v5.16.19~64
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b80b19b32a432c9eee1cd200ef7aaddf608f54d1;p=thirdparty%2Fkernel%2Fstable.git

ACPI: CPPC: Avoid out of bounds access when parsing _CPC data

commit 40d8abf364bcab23bc715a9221a3c8623956257b upstream.

If the NumEntries field in the _CPC return package is less than 2, do
not attempt to access the "Revision" element of that package, because
it may not be present then.

Fixes: 337aadff8e45 ("ACPI: Introduce CPU performance controls using CPPC")
BugLink: https://lore.kernel.org/lkml/20220322143534.GC32582@xsang-OptiPlex-9020/
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 12a156d8283e6..c496604fc9459 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -690,6 +690,11 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 	cpc_obj = &out_obj->package.elements[0];
 	if (cpc_obj->type == ACPI_TYPE_INTEGER)	{
 		num_ent = cpc_obj->integer.value;
+		if (num_ent <= 1) {
+			pr_debug("Unexpected _CPC NumEntries value (%d) for CPU:%d\n",
+				 num_ent, pr->id);
+			goto out_free;
+		}
 	} else {
 		pr_debug("Unexpected entry type(%d) for NumEntries\n",
 				cpc_obj->type);