svn commit: r197348 - head/sys/vm

[Konstantin Belousov]

Author: kib
Date: Sun Sep 20 12:40:56 2009
New Revision: 197348
URL: http://svn.freebsd.org/changeset/base/197348

Log:
  Old (a.out) rtld attempts to mmap zero-length region, e.g. when bss
  of the linked object is zero-length. More old code assumes that mmap
  of zero length returns success.
  
  For a.out and pre-8 ELF binaries, allow the mmap of zero length.
  
  Reported by:	tegge
  Reviewed by:	tegge, alc, jhb
  MFC after:	3 days

Modified:
  head/sys/vm/vm_mmap.c

Modified: head/sys/vm/vm_mmap.c
==============================================================================
--- head/sys/vm/vm_mmap.c	Sun Sep 20 12:24:55 2009	(r197347)
+++ head/sys/vm/vm_mmap.c	Sun Sep 20 12:40:56 2009	(r197348)
@@ -64,6 +64,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/mount.h>
 #include <sys/conf.h>
 #include <sys/stat.h>
+#include <sys/sysent.h>
 #include <sys/vmmeter.h>
 #include <sys/sysctl.h>
 
@@ -229,7 +230,8 @@ mmap(td, uap)
 
 	fp = NULL;
 	/* make sure mapping fits into numeric range etc */
-	if (uap->len == 0 ||
+	if ((uap->len == 0 && !SV_CURPROC_FLAG(SV_AOUT) &&
+	     curproc->p_osrel >= 800104) ||
 	    ((flags & MAP_ANON) && uap->fd != -1))
 		return (EINVAL);