platform/x86: asus-wmi: Potential buffer overflow in asus_wmi_evaluate_method_buf()

[ Upstream commit 4345ece8f0bcc682f1fb3b648922c9be5f7dbe6c ]

This code tests for if the obj->buffer.length is larger than the buffer
but then it just does the memcpy() anyway.

Fixes: 0f0ac158d28f ("platform/x86: asus-wmi: Add support for custom fan curves")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220413073744.GB8812@kili
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index adab31b52f2af348bbc35e70c8830cf6a3344a8a..399a4a345224c907a5824a63cd292ca81bbd1902 100644 (file)
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -371,10 +371,14 @@ static int asus_wmi_evaluate_method_buf(u32 method_id,
 
        switch (obj->type) {
        case ACPI_TYPE_BUFFER:
-               if (obj->buffer.length > size)
+               if (obj->buffer.length > size) {
                        err = -ENOSPC;
-               if (obj->buffer.length == 0)
+                       break;
+               }
+               if (obj->buffer.length == 0) {
                        err = -ENODATA;
+                       break;
+               }
 
                memcpy(ret_buffer, obj->buffer.pointer, obj->buffer.length);
                break;