ALSA: asihpi - Clarify adapter index validity check

Avoids assigning possibly invalid address to pa, even if it
is never dereferenced.
Correct error response to reflect request object/function ids.

Signed-off-by: Eliot Blennerhassett <eblennerhassett@audioscience.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 12 insertions, 7 deletions

diff --git a/sound/pci/asihpi/hpioctl.c b/sound/pci/asihpi/hpioctl.c
index 9683f84ecdc8..a32502e796de 100644
--- a/sound/pci/asihpi/hpioctl.c
+++ b/sound/pci/asihpi/hpioctl.c
@@ -177,16 +177,21 @@ long asihpi_hpi_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         } else {
                 u16 __user *ptr = NULL;
                 u32 size = 0;
-
+                u32 adapter_present;
                 /* -1=no data 0=read from user mem, 1=write to user mem */
                 int wrflag = -1;
-                u32 adapter = hm->h.adapter_index;
-                struct hpi_adapter *pa = &adapters[adapter];
+                struct hpi_adapter *pa;
+
+                if (hm->h.adapter_index < HPI_MAX_ADAPTERS) {
+                        pa = &adapters[hm->h.adapter_index];
+                        adapter_present = pa->type;
+                } else {
+                        adapter_present = 0;
+                }
 
-                if ((adapter >= HPI_MAX_ADAPTERS) || (!pa->type)) {
-                        hpi_init_response(&hr->r0, HPI_OBJ_ADAPTER,
-                                HPI_ADAPTER_OPEN,
-                                HPI_ERROR_BAD_ADAPTER_NUMBER);
+                if (!adapter_present) {
+                        hpi_init_response(&hr->r0, hm->h.object,
+                                hm->h.function, HPI_ERROR_BAD_ADAPTER_NUMBER);
 
                         uncopied_bytes =
                                 copy_to_user(puhr, hr, sizeof(hr->h));