scsi: ses: Fix possible addl_desc_ptr out-of-bounds accesses

Sanitize possible addl_desc_ptr out-of-bounds accesses in
ses_enclosure_data_process().

Link: https://lore.kernel.org/r/20230202162451.15346-3-thenzl@redhat.com
Cc: stable@vger.kernel.org
Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ses.c

@@ -439,8 +439,8 @@ int ses_match_host(struct enclosure_device *edev, void *data)
 }
 #endif  /*  0  */
 
-static void ses_process_descriptor(struct enclosure_component *ecomp,
-				   unsigned char *desc)
+static int ses_process_descriptor(struct enclosure_component *ecomp,
+				   unsigned char *desc, int max_desc_len)
 {
 	int eip = desc[0] & 0x10;
 	int invalid = desc[0] & 0x80;
@@ -451,22 +451,32 @@ static void ses_process_descriptor(struct enclosure_component *ecomp,
 	unsigned char *d;
 
 	if (invalid)
-		return;
+		return 0;
 
 	switch (proto) {
 	case SCSI_PROTOCOL_FCP:
 		if (eip) {
+			if (max_desc_len <= 7)
+				return 1;
 			d = desc + 4;
 			slot = d[3];
 		}
 		break;
 	case SCSI_PROTOCOL_SAS:
+
 		if (eip) {
+			if (max_desc_len <= 27)
+				return 1;
 			d = desc + 4;
 			slot = d[3];
 			d = desc + 8;
-		} else
+		} else {
+			if (max_desc_len <= 23)
+				return 1;
 			d = desc + 4;
+		}
+
+
 		/* only take the phy0 addr */
 		addr = (u64)d[12] << 56 |
 			(u64)d[13] << 48 |
@@ -483,6 +493,8 @@ static void ses_process_descriptor(struct enclosure_component *ecomp,
 	}
 	ecomp->slot = slot;
 	scomp->addr = addr;
+
+	return 0;
 }
 
 struct efd {
@@ -555,7 +567,7 @@ static void ses_enclosure_data_process(struct enclosure_device *edev,
 		/* skip past overall descriptor */
 		desc_ptr += len + 4;
 	}
-	if (ses_dev->page10)
+	if (ses_dev->page10 && ses_dev->page10_len > 9)
 		addl_desc_ptr = ses_dev->page10 + 8;
 	type_ptr = ses_dev->page1_types;
 	components = 0;
@@ -563,6 +575,7 @@ static void ses_enclosure_data_process(struct enclosure_device *edev,
 		for (j = 0; j < type_ptr[1]; j++) {
 			char *name = NULL;
 			struct enclosure_component *ecomp;
+			int max_desc_len;
 
 			if (desc_ptr) {
 				if (desc_ptr >= buf + page7_len) {
@@ -589,10 +602,14 @@ static void ses_enclosure_data_process(struct enclosure_device *edev,
 					ecomp = &edev->component[components++];
 
 				if (!IS_ERR(ecomp)) {
-					if (addl_desc_ptr)
-						ses_process_descriptor(
-							ecomp,
-							addl_desc_ptr);
+					if (addl_desc_ptr) {
+						max_desc_len = ses_dev->page10_len -
+						    (addl_desc_ptr - ses_dev->page10);
+						if (ses_process_descriptor(ecomp,
+						    addl_desc_ptr,
+						    max_desc_len))
+							addl_desc_ptr = NULL;
+					}
 					if (create)
 						enclosure_component_register(
 							ecomp);