svn commit: r307523 - head/sys/cam/scsi

[Alexander Motin]

Author: mav
Date: Mon Oct 17 15:02:17 2016
New Revision: 307523
URL: https://svnweb.freebsd.org/changeset/base/307523

Log:
  Make pass driver better support CAM_CDB_POINTER flag.
  
  Previously pass driver just ignored the flag, making random kernel code
  access user-space pointer, sometime causing crashes even for correctly
  written applications if user-level context was switched or swapped out.
  This patch tries to copyin the CDB into kernel space to avoid it.
  
  MFC after:	2 weeks

Modified:
  head/sys/cam/scsi/scsi_pass.c

Modified: head/sys/cam/scsi/scsi_pass.c
==============================================================================
--- head/sys/cam/scsi/scsi_pass.c	Mon Oct 17 13:52:24 2016	(r307522)
+++ head/sys/cam/scsi/scsi_pass.c	Mon Oct 17 15:02:17 2016	(r307523)
@@ -1876,6 +1876,18 @@ passdoioctl(struct cdev *dev, u_long cmd
 			break;
 		}
 
+		if (ccb->ccb_h.flags & CAM_CDB_POINTER) {
+			if (ccb->csio.cdb_len > IOCDBLEN) {
+				error = EINVAL;
+				break;
+			}
+			error = copyin(ccb->csio.cdb_io.cdb_ptr,
+			    ccb->csio.cdb_io.cdb_bytes, ccb->csio.cdb_len);
+			if (error)
+				break;
+			ccb->ccb_h.flags &= ~CAM_CDB_POINTER;
+		}
+
 		/*
 		 * Some CCB types, like scan bus and scan lun can only go
 		 * through the transport layer device.
@@ -2143,6 +2155,7 @@ passsendccb(struct cam_periph *periph, u
 {
 	struct pass_softc *softc;
 	struct cam_periph_map_info mapinfo;
+	uint8_t *cmd;
 	xpt_opcode fc;
 	int error;
 
@@ -2154,6 +2167,14 @@ passsendccb(struct cam_periph *periph, u
 	 */
 	xpt_merge_ccb(ccb, inccb);
 
+	if (ccb->ccb_h.flags & CAM_CDB_POINTER) {
+		cmd = __builtin_alloca(ccb->csio.cdb_len);
+		error = copyin(ccb->csio.cdb_io.cdb_ptr, cmd, ccb->csio.cdb_len);
+		if (error)
+			return (error);
+		ccb->csio.cdb_io.cdb_ptr = cmd;
+	}
+
 	/*
 	 */
 	ccb->ccb_h.cbfcnp = passdone;