From d5c13047a132162d2649be876906ead691d12948 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 9 Jul 2026 14:30:35 +0200 Subject: [PATCH] ACPI: processor: idle: Expand _LPI package sanity checks The _LPI package sanity checks in acpi_processor_evaluate_lpi() miss a couple of things, so expand them by adding a buffer size check before retrieving a struct acpi_power_register from it (and skip the given state if the buffer is not large enough to hold a register structure) and making the function avoid copying the state description from the ACPI table if there are too few elements in the package supposed to hold it. While at it, relocate and rephrase a comment about skipping _LPI state package elements [7-8]. Fixes: a36a7fecfe60 ("ACPI / processor_idle: Add support for Low Power Idle(LPI) states") Signed-off-by: Rafael J. Wysocki Reviewed-by: Sudeep Holla Acked-by: Huisong Li Link: https://patch.msgid.link/5084143.GXAFRqVoOG@rafael.j.wysocki --- drivers/acpi/processor_idle.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 4482cf28f56a..d573f201295a 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -927,6 +927,13 @@ static int acpi_processor_evaluate_lpi(acpi_handle handle, if (obj->type == ACPI_TYPE_BUFFER) { struct acpi_power_register *reg; + if (obj->buffer.length < sizeof(*reg)) { + acpi_handle_debug(handle, + "Invalid register data for _LPI state %d\n", + state_idx); + continue; + } + reg = (struct acpi_power_register *)obj->buffer.pointer; if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO && reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) @@ -945,13 +952,6 @@ static int acpi_processor_evaluate_lpi(acpi_handle handle, continue; } - /* elements[7,8] skipped for now i.e. Residency/Usage counter*/ - - obj = pkg_elem + 9; - if (obj->type == ACPI_TYPE_STRING) - strscpy(lpi_state->desc, obj->string.pointer, - ACPI_CX_DESC_LEN); - lpi_state->index = state_idx; if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) { pr_debug("No min. residency found, assuming 10 us\n"); @@ -974,6 +974,20 @@ static int acpi_processor_evaluate_lpi(acpi_handle handle, if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state)) lpi_state->enable_parent_state = 0; + + /* Skip elements [7-8] i.e. Residency/Usage counters. */ + + /* + * Avoid out-of-bounds access if the size of the package is less + * than expected. + */ + if (element->package.count < 10) + continue; + + obj = pkg_elem + 9; + if (obj->type == ACPI_TYPE_STRING) + strscpy(lpi_state->desc, obj->string.pointer, + ACPI_CX_DESC_LEN); } acpi_handle_debug(handle, "Found %d power states\n", state_idx);