panasonic-laptop: avoid overflow in acpi_pcc_hotkey_add()

num_sifr could go negative since acpi_pcc_get_sqty() returns -EINVAL
on error.  Then it could bypass the sanity check (num_sifr > 255).
The subsequent call to kzalloc() would allocate a small buffer, leading
to a memory corruption.

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
This commit is contained in:
Xi Wang 2011-12-28 23:49:06 -05:00 committed by Matthew Garrett
parent 461e74377c
commit e424fb8cc4

View File

@ -562,8 +562,8 @@ static int acpi_pcc_hotkey_add(struct acpi_device *device)
num_sifr = acpi_pcc_get_sqty(device);
if (num_sifr > 255) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "num_sifr too large"));
if (num_sifr < 0 || num_sifr > 255) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "num_sifr out of range"));
return -ENODEV;
}