more validity checking in reading block devices

SCCS-vsn: sys/miscfs/specfs/spec_vnops.c 8.4

diff --git a/usr/src/sys/miscfs/specfs/spec_vnops.c b/usr/src/sys/miscfs/specfs/spec_vnops.c
index 9338605..02bb220 100644 (file)
--- a/usr/src/sys/miscfs/specfs/spec_vnops.c
+++ b/usr/src/sys/miscfs/specfs/spec_vnops.c
@@ -4,7 +4,7 @@
  *
  * %sccs.include.redist.c%
  *
  *
  * %sccs.include.redist.c%
  *

- *     @(#)spec_vnops.c        8.3 (Berkeley) %G%
+ *     @(#)spec_vnops.c        8.4 (Berkeley) %G%

  */
 
 #include <sys/param.h>
  */
 
 #include <sys/param.h>


@@ -192,8 +192,9 @@ spec_read(ap)
        daddr_t bn, nextbn;
        long bsize, bscale;
        struct partinfo dpart;
        daddr_t bn, nextbn;
        long bsize, bscale;
        struct partinfo dpart;

-       register int n, on;
+       int n, on, majordev, (*ioctl)();

        int error = 0;
        int error = 0;

+       dev_t dev;

 
 #ifdef DIAGNOSTIC
        if (uio->uio_rw != UIO_READ)
 
 #ifdef DIAGNOSTIC
        if (uio->uio_rw != UIO_READ)


@@ -217,13 +218,13 @@ spec_read(ap)
                if (uio->uio_offset < 0)
                        return (EINVAL);
                bsize = BLKDEV_IOSIZE;
                if (uio->uio_offset < 0)
                        return (EINVAL);
                bsize = BLKDEV_IOSIZE;

-               if ((*bdevsw[major(vp->v_rdev)].d_ioctl)(vp->v_rdev, DIOCGPART,
-                   (caddr_t)&dpart, FREAD, p) == 0) {
-                       if (dpart.part->p_fstype == FS_BSDFFS &&
-                           dpart.part->p_frag != 0 && dpart.part->p_fsize != 0)
-                               bsize = dpart.part->p_frag *
-                                   dpart.part->p_fsize;
-               }
+               dev = vp->v_rdev;
+               if ((majordev = major(dev)) < nblkdev &&
+                   (ioctl = bdevsw[majordev].d_ioctl) != NULL &&
+                   (*ioctl)(dev, DIOCGPART, (caddr_t)&dpart, FREAD, p) == 0 &&
+                   dpart.part->p_fstype == FS_BSDFFS &&
+                   dpart.part->p_frag != 0 && dpart.part->p_fsize != 0)
+                       bsize = dpart.part->p_frag * dpart.part->p_fsize;

                bscale = bsize / DEV_BSIZE;
                do {
                        bn = (uio->uio_offset / DEV_BSIZE) &~ (bscale - 1);
                bscale = bsize / DEV_BSIZE;
                do {
                        bn = (uio->uio_offset / DEV_BSIZE) &~ (bscale - 1);