[src/trunk]: src/sys/dev/filemon Retrieve the pathname of the exec'd file bef...

[pgoyette <pgoyette%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0e80b8a2e4dc
branches:  trunk
changeset: 811944:0e80b8a2e4dc
user:      pgoyette <pgoyette%NetBSD.org@localhost>
date:      Mon Nov 23 00:47:43 2015 +0000

description:
Retrieve the pathname of the exec'd file before we call sys_execve().

We cannot rely on using copyinstr() to retrieve the pathname from
user mode after a successful exec, since the user mode address space
is no longer valid (and may not even be accessible).  This worked in
earlier code but was broken by rev 1.7.

diffstat:

 sys/dev/filemon/filemon_wrapper.c |  13 +++++++------
 1 files changed, 7 insertions(+), 6 deletions(-)

diffs (43 lines):

diff -r 075a8b4182b5 -r 0e80b8a2e4dc sys/dev/filemon/filemon_wrapper.c
--- a/sys/dev/filemon/filemon_wrapper.c Sun Nov 22 20:47:42 2015 +0000
+++ b/sys/dev/filemon/filemon_wrapper.c Mon Nov 23 00:47:43 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: filemon_wrapper.c,v 1.9 2015/11/22 01:20:52 pgoyette Exp $     */
+/*     $NetBSD: filemon_wrapper.c,v 1.10 2015/11/23 00:47:43 pgoyette Exp $    */
 
 /*
  * Copyright (c) 2010, Juniper Networks, Inc.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: filemon_wrapper.c,v 1.9 2015/11/22 01:20:52 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: filemon_wrapper.c,v 1.10 2015/11/23 00:47:43 pgoyette Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -71,10 +71,12 @@
     register_t * retval)
 {
        char fname[MAXPATHLEN];
-       int error;
+       int error, cerror;
        size_t done;
        struct filemon *filemon;
-       
+
+       cerror = copyinstr(SCARG(uap, path), fname, sizeof(fname), &done);
+
        if ((error = sys_execve(l, uap, retval)) != EJUSTRETURN)
                return error;
 
@@ -82,8 +84,7 @@
        if (filemon == NULL)
                return EJUSTRETURN;
 
-       error = copyinstr(SCARG(uap, path), fname, sizeof(fname), &done);
-       if (error)
+       if (cerror)
                goto out;
 
        filemon_printf(filemon, "E %d %s\n", curproc->p_pid, fname);