From 4222f38ca3b7ae30ace582077677cec8b88fac36 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Fri, 9 Feb 2018 17:38:33 +0200 Subject: ACPI / bus: Do not traverse through non-existed device table When __acpi_match_device() is called it would be possible to have ACPI ID table a NULL pointer. To avoid potential dereference, check for this before traverse. While here, remove redundant 'else'. Note, this patch implies a bit of refactoring acpi_of_match_device() to return pointer to OF ID when matched followed by refactoring __acpi_match_device() to return either ACPI or OF ID when matches. Signed-off-by: Andy Shevchenko Reviewed-by: Mika Westerberg Signed-off-by: Rafael J. Wysocki --- drivers/acpi/bus.c | 63 ++++++++++++++++++++++++++++++++---------------------- 1 file changed, 38 insertions(+), 25 deletions(-) (limited to 'drivers') diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index 676c9788e1c8..f1384e107eed 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -660,13 +660,15 @@ struct acpi_device *acpi_companion_match(const struct device *dev) * acpi_of_match_device - Match device object using the "compatible" property. * @adev: ACPI device object to match. * @of_match_table: List of device IDs to match against. + * @of_id: OF ID if matched * * If @dev has an ACPI companion which has ACPI_DT_NAMESPACE_HID in its list of * identifiers and a _DSD object with the "compatible" property, use that * property to match against the given list of identifiers. */ static bool acpi_of_match_device(struct acpi_device *adev, - const struct of_device_id *of_match_table) + const struct of_device_id *of_match_table, + const struct of_device_id **of_id) { const union acpi_object *of_compatible, *obj; int i, nval; @@ -690,8 +692,11 @@ static bool acpi_of_match_device(struct acpi_device *adev, const struct of_device_id *id; for (id = of_match_table; id->compatible[0]; id++) - if (!strcasecmp(obj->string.pointer, id->compatible)) + if (!strcasecmp(obj->string.pointer, id->compatible)) { + if (of_id) + *of_id = id; return true; + } } return false; @@ -762,10 +767,11 @@ static bool __acpi_match_device_cls(const struct acpi_device_id *id, return true; } -static const struct acpi_device_id *__acpi_match_device( - struct acpi_device *device, - const struct acpi_device_id *ids, - const struct of_device_id *of_ids) +static bool __acpi_match_device(struct acpi_device *device, + const struct acpi_device_id *acpi_ids, + const struct of_device_id *of_ids, + const struct acpi_device_id **acpi_id, + const struct of_device_id **of_id) { const struct acpi_device_id *id; struct acpi_hardware_id *hwid; @@ -775,30 +781,32 @@ static const struct acpi_device_id *__acpi_match_device( * driver for it. */ if (!device || !device->status.present) - return NULL; + return false; list_for_each_entry(hwid, &device->pnp.ids, list) { /* First, check the ACPI/PNP IDs provided by the caller. */ - for (id = ids; id->id[0] || id->cls; id++) { - if (id->id[0] && !strcmp((char *) id->id, hwid->id)) - return id; - else if (id->cls && __acpi_match_device_cls(id, hwid)) - return id; + if (acpi_ids) { + for (id = acpi_ids; id->id[0] || id->cls; id++) { + if (id->id[0] && !strcmp((char *)id->id, hwid->id)) + goto out_acpi_match; + if (id->cls && __acpi_match_device_cls(id, hwid)) + goto out_acpi_match; + } } /* * Next, check ACPI_DT_NAMESPACE_HID and try to match the * "compatible" property if found. - * - * The id returned by the below is not valid, but the only - * caller passing non-NULL of_ids here is only interested in - * whether or not the return value is NULL. */ - if (!strcmp(ACPI_DT_NAMESPACE_HID, hwid->id) - && acpi_of_match_device(device, of_ids)) - return id; + if (!strcmp(ACPI_DT_NAMESPACE_HID, hwid->id)) + return acpi_of_match_device(device, of_ids, of_id); } - return NULL; + return false; + +out_acpi_match: + if (acpi_id) + *acpi_id = id; + return true; } /** @@ -815,7 +823,10 @@ static const struct acpi_device_id *__acpi_match_device( const struct acpi_device_id *acpi_match_device(const struct acpi_device_id *ids, const struct device *dev) { - return __acpi_match_device(acpi_companion_match(dev), ids, NULL); + const struct acpi_device_id *id = NULL; + + __acpi_match_device(acpi_companion_match(dev), ids, NULL, &id, NULL); + return id; } EXPORT_SYMBOL_GPL(acpi_match_device); @@ -840,7 +851,7 @@ EXPORT_SYMBOL_GPL(acpi_get_match_data); int acpi_match_device_ids(struct acpi_device *device, const struct acpi_device_id *ids) { - return __acpi_match_device(device, ids, NULL) ? 0 : -ENOENT; + return __acpi_match_device(device, ids, NULL, NULL, NULL) ? 0 : -ENOENT; } EXPORT_SYMBOL(acpi_match_device_ids); @@ -849,10 +860,12 @@ bool acpi_driver_match_device(struct device *dev, { if (!drv->acpi_match_table) return acpi_of_match_device(ACPI_COMPANION(dev), - drv->of_match_table); + drv->of_match_table, + NULL); - return !!__acpi_match_device(acpi_companion_match(dev), - drv->acpi_match_table, drv->of_match_table); + return __acpi_match_device(acpi_companion_match(dev), + drv->acpi_match_table, drv->of_match_table, + NULL, NULL); } EXPORT_SYMBOL_GPL(acpi_driver_match_device); -- cgit v1.2.3