svn commit: r355101 - head/sys/dev/cfi

[Ed Maste]

Author: emaste
Date: Mon Nov 25 21:21:37 2019
New Revision: 355101
URL: https://svnweb.freebsd.org/changeset/base/355101

Log:
  cfi: check for inter overflow in cfi_devioctl
  
  Reported by:    Pietro Oliva
  Reviewed by:	markj
  MFC after:	3 days
  Security:	Possible OOB read in root-only ioctl
  Sponsored by:	The FreeBSD Foundation

Modified:
  head/sys/dev/cfi/cfi_dev.c

Modified: head/sys/dev/cfi/cfi_dev.c
==============================================================================
--- head/sys/dev/cfi/cfi_dev.c	Mon Nov 25 19:59:53 2019	(r355100)
+++ head/sys/dev/cfi/cfi_dev.c	Mon Nov 25 21:21:37 2019	(r355101)
@@ -280,7 +280,8 @@ cfi_devioctl(struct cdev *dev, u_long cmd, caddr_t dat
 		rq = (struct cfiocqry *)data;
 		if (rq->offset >= sc->sc_size / sc->sc_width)
 			return (ESPIPE);
-		if (rq->offset + rq->count > sc->sc_size / sc->sc_width)
+		if (rq->offset > ULONG_MAX - rq->count ||
+		    rq->offset + rq->count > sc->sc_size / sc->sc_width)
 			return (ENOSPC);
 
 		while (!error && rq->count--) {