d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

EEEK!!! useracc and kernacc didn't lock their respective

Browse Source 
maps.  Additionally, eliminate the map->hint distortion
associated with useracc.  That may/may-not be the "right"
thing to do -- but time will tell.
Submitted by:	Partially by Alan Cox <alc@cs.rice.edu>
This commit is contained in:
John Dyson 1996-12-30 03:56:11 +00:00
parent 630a47cfec
commit bc0d333478
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=21037
1 changed files with 16 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
sys/vm/vm_glue.c
View File

@ -59,7 +59,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: vm_glue.c,v 1.55 1996/10/17 02:58:20 dyson Exp $
* $Id: vm_glue.c,v 1.56 1996/12/22 23:17:09 joerg Exp $
*/
#include "opt_rlimit.h"
@ -126,7 +126,9 @@ kernacc(addr, len, rw)
saddr = trunc_page(addr);
eaddr = round_page(addr + len);
vm_map_lock_read(kernel_map);
rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
vm_map_unlock_read(kernel_map);
return (rv == TRUE);
}
@ -137,6 +139,8 @@ useracc(addr, len, rw)
{
boolean_t rv;
vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
vm_map_t map;
vm_map_entry_t save_hint;
/*
* XXX - check separately to disallow access to user area and user
@ -151,8 +155,18 @@ useracc(addr, len, rw)
|| (vm_offset_t) addr + len < (vm_offset_t) addr) {
return (FALSE);
}
rv = vm_map_check_protection(&curproc->p_vmspace->vm_map,
map = &curproc->p_vmspace->vm_map;
vm_map_lock_read(map);
/*
* We save the map hint, and restore it. Useracc appears to distort
* the map hint unnecessarily.
*/
save_hint = map->hint;
rv = vm_map_check_protection(map,
trunc_page(addr), round_page(addr + len), prot);
map->hint = save_hint;
vm_map_unlock_read(map);
return (rv == TRUE);
}