From: Hans de Goede hdegoede@redhat.com
[ Upstream commit 5e3f5973c8dfd2b80268f1825ed2f2ddf81d3267 ]
Make init_bios_attributes() ACPI object parsing more robust: 1. Always check that the type of the return ACPI object is package, rather then only checking this for instance_id == 0 2. Check that the package has the minimum amount of elements which will be consumed by the populate_foo_data() for the attr_type
Note/TODO: The populate_foo_data() functions should also be made more robust. The should check the type of each of the elements matches the type which they expect and in case of populate_enum_data() obj->package.count should be passed to it as an argument and it should re-check this itself since it consume a variable number of elements.
Fixes: e8a60aa7404b ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems") Cc: Divya Bharathi Divya_Bharathi@dell.com Cc: Mario Limonciello mario.limonciello@dell.com Signed-off-by: Hans de Goede hdegoede@redhat.com Link: https://lore.kernel.org/r/20210321121607.35717-1-hdegoede@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../x86/dell/dell-wmi-sysman/sysman.c | 32 ++++++++++++++++--- 1 file changed, 28 insertions(+), 4 deletions(-)
diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c b/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c index 7410ccae650c..a90ae6ba4a73 100644 --- a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c +++ b/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c @@ -399,6 +399,7 @@ static int init_bios_attributes(int attr_type, const char *guid) union acpi_object *obj = NULL; union acpi_object *elements; struct kset *tmp_set; + int min_elements;
/* instance_id needs to be reset for each type GUID * also, instance IDs are unique within GUID but not across @@ -409,14 +410,38 @@ static int init_bios_attributes(int attr_type, const char *guid) retval = alloc_attributes_data(attr_type); if (retval) return retval; + + switch (attr_type) { + case ENUM: min_elements = 8; break; + case INT: min_elements = 9; break; + case STR: min_elements = 8; break; + case PO: min_elements = 4; break; + default: + pr_err("Error: Unknown attr_type: %d\n", attr_type); + return -EINVAL; + } + /* need to use specific instance_id and guid combination to get right data */ obj = get_wmiobj_pointer(instance_id, guid); - if (!obj || obj->type != ACPI_TYPE_PACKAGE) + if (!obj) return -ENODEV; - elements = obj->package.elements;
mutex_lock(&wmi_priv.mutex); - while (elements) { + while (obj) { + if (obj->type != ACPI_TYPE_PACKAGE) { + pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type); + retval = -EIO; + goto err_attr_init; + } + + if (obj->package.count < min_elements) { + pr_err("Error: ACPI-package does not have enough elements: %d < %d\n", + obj->package.count, min_elements); + goto nextobj; + } + + elements = obj->package.elements; + /* sanity checking */ if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) { pr_debug("incorrect element type\n"); @@ -481,7 +506,6 @@ nextobj: kfree(obj); instance_id++; obj = get_wmiobj_pointer(instance_id, guid); - elements = obj ? obj->package.elements : NULL; }
mutex_unlock(&wmi_priv.mutex);