svn commit: r219595 - stable/7/sys/kern

[Konstantin Belousov]

Author: kib
Date: Sun Mar 13 10:08:02 2011
New Revision: 219595
URL: http://svn.freebsd.org/changeset/base/219595

Log:
  MFC r219352:
  The execution of the shebang script requires putting interpreter path,
  possible option and script path in the place of argv[0] supplied to
  execve(2).  It is possible and valid for the substitution to be shorter
  then the argv[0].
  
  Avoid signed underflow in this case.
  
  PR:     kern/155321

Modified:
  stable/7/sys/kern/imgact_shell.c
Directory Properties:
  stable/7/sys/   (props changed)
  stable/7/sys/cddl/contrib/opensolaris/   (props changed)
  stable/7/sys/contrib/dev/acpica/   (props changed)
  stable/7/sys/contrib/pf/   (props changed)

Modified: stable/7/sys/kern/imgact_shell.c
==============================================================================
--- stable/7/sys/kern/imgact_shell.c	Sun Mar 13 09:36:52 2011	(r219594)
+++ stable/7/sys/kern/imgact_shell.c	Sun Mar 13 10:08:02 2011	(r219595)
@@ -179,7 +179,7 @@ exec_shell_imgact(imgp)
 	length = (imgp->args->argc == 0) ? 0 :
 	    strlen(imgp->args->begin_argv) + 1;		/* bytes to delete */
 
-	if (offset - length > imgp->args->stringspace)
+	if (offset > imgp->args->stringspace + length) {
 		return (E2BIG);
 
 	bcopy(imgp->args->begin_argv + length, imgp->args->begin_argv + offset,