svn commit: r192012 - head/sys/fs/fdescfs

[Konstantin Belousov]

Author: kib
Date: Tue May 12 09:22:33 2009
New Revision: 192012
URL: http://svn.freebsd.org/changeset/base/192012

Log:
  Return controlled EINVAL when the fdescfs lookup routine is given string
  representing too large integer, instead of overflowing and possibly
  returning a random but valid vnode.
  
  Noted by:	Jilles Tjoelker <jilles stack nl>
  MFC after:	3 days

Modified:
  head/sys/fs/fdescfs/fdesc_vnops.c

Modified: head/sys/fs/fdescfs/fdesc_vnops.c
==============================================================================
--- head/sys/fs/fdescfs/fdesc_vnops.c	Tue May 12 07:41:20 2009	(r192011)
+++ head/sys/fs/fdescfs/fdesc_vnops.c	Tue May 12 09:22:33 2009	(r192012)
@@ -265,7 +265,7 @@ fdesc_lookup(ap)
 	struct thread *td = cnp->cn_thread;
 	struct file *fp;
 	int nlen = cnp->cn_namelen;
-	u_int fd;
+	u_int fd, fd1;
 	int error;
 	struct vnode *fvp;
 
@@ -297,7 +297,12 @@ fdesc_lookup(ap)
 			error = ENOENT;
 			goto bad;
 		}
-		fd = 10 * fd + *pname++ - '0';
+		fd1 = 10 * fd + *pname++ - '0';
+		if (fd1 < fd) {
+			error = ENOENT;
+			goto bad;
+		}
+		fd = fd1;
 	}
 
 	if ((error = fget(td, fd, &fp)) != 0)