1 files changed, 28 insertions, 8 deletions

diff --git a/include/linux/ipmi_smi.h b/include/linux/ipmi_smi.h
index c0633108d05d..efa292a52e7e 100644
--- a/include/linux/ipmi_smi.h
+++ b/include/linux/ipmi_smi.h
@@ -148,26 +148,46 @@ struct ipmi_device_id {
 
 /* Take a pointer to a raw data buffer and a length and extract device
    id information from it.  The first byte of data must point to the
-   byte from the get device id response after the completion code.
-   The caller is responsible for making sure the length is at least
-   11 and the command completed without error. */
-static inline void ipmi_demangle_device_id(unsigned char *data,
-					   unsigned int  data_len,
-					   struct ipmi_device_id *id)
+   netfn << 2, the data should be of the format:
+      netfn << 2, cmd, completion code, data
+   as normally comes from a device interface. */
+static inline int ipmi_demangle_device_id(const unsigned char *data,
+					  unsigned int data_len,
+					  struct ipmi_device_id *id)
 {
+	if (data_len < 9)
+		return -EINVAL;
+	if (data[0] != IPMI_NETFN_APP_RESPONSE << 2 ||
+	    data[1] != IPMI_GET_DEVICE_ID_CMD)
+		/* Strange, didn't get the response we expected. */
+		return -EINVAL;
+	if (data[2] != 0)
+		/* That's odd, it shouldn't be able to fail. */
+		return -EINVAL;
+
+	data += 3;
+	data_len -= 3;
 	id->device_id = data[0];
 	id->device_revision = data[1];
 	id->firmware_revision_1 = data[2];
 	id->firmware_revision_2 = data[3];
 	id->ipmi_version = data[4];
 	id->additional_device_support = data[5];
-	id->manufacturer_id = data[6] | (data[7] << 8) | (data[8] << 16);
-	id->product_id = data[9] | (data[10] << 8);
+	if (data_len >= 6) {
+		id->manufacturer_id = (data[6] | (data[7] << 8) |
+				       (data[8] << 16));
+		id->product_id = data[9] | (data[10] << 8);
+	} else {
+		id->manufacturer_id = 0;
+		id->product_id = 0;
+	}
 	if (data_len >= 15) {
 		memcpy(id->aux_firmware_revision, data+11, 4);
 		id->aux_firmware_revision_set = 1;
 	} else
 		id->aux_firmware_revision_set = 0;
+
+	return 0;
 }
 
 /* Add a low-level interface to the IPMI driver.  Note that if the