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do the "right thing" with mmap protections, once and for all.

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in particular, if an object is mapped private, DO NOT grant
VM_PROT_ALL protections to it; it could be sensitive data.
This commit is contained in:
cgd 1993-07-15 14:48:37 +00:00
parent b8b3b4471d
commit 4b90229cd2
1 changed files with 14 additions and 18 deletions
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32
sys/vm/vm_mmap.c
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@ -38,7 +38,7 @@
* from: Utah $Hdr: vm_mmap.c 1.3 90/01/21$
*
* from: @(#)vm_mmap.c 7.5 (Berkeley) 6/28/91
* $Id: vm_mmap.c,v 1.8 1993/07/07 11:25:32 cgd Exp $
* $Id: vm_mmap.c,v 1.9 1993/07/15 14:48:37 cgd Exp $
*/
/*
@ -131,7 +131,7 @@ smmap(p, uap, retval)
if (mmapdebug & MDB_FOLLOW)
printf("mmap(%d): addr %x len %x pro %x flg %x fd %d pos %x\n",
p->p_pid, uap->addr, uap->len, uap->prot,
uap->flags, uap->fd, uap->pos);
flags, uap->fd, uap->pos);
#endif
/*
* Make sure one of the sharing types is specified
@ -187,7 +187,8 @@ smmap(p, uap, retval)
/*
* Ensure that file protection and desired protection
* are compatible. Note that we only worry about writability
* if mapping is shared.
* if mapping is shared. XXX (cgd) -- coalese access checks
* and permissions setting.
*/
if ((uap->prot & PROT_READ) && (fp->f_flag & FREAD) == 0 ||
((flags & MAP_SHARED) &&
@ -195,17 +196,16 @@ smmap(p, uap, retval)
return(EACCES);
handle = (caddr_t)vp;
/*
* Map protections to MACH style
* Map maximum protections to MACH style
*/
if(flags & MAP_SHARED) {
maxprot = VM_PROT_EXECUTE;
if (fp->f_flag & FREAD)
maxprot |= VM_PROT_READ;
maxprot = VM_PROT_EXECUTE; /* ??? */
if (fp->f_flag & FREAD)
maxprot |= VM_PROT_READ;
if(uap->flags & MAP_SHARED) {
if (fp->f_flag & FWRITE)
maxprot |= VM_PROT_WRITE;
} else {
maxprot = VM_PROT_ALL;
}
} else
maxprot |= VM_PROT_WRITE;
} else if (uap->fd != -1) {
maxprot = VM_PROT_ALL;
handle = (caddr_t)fp;
@ -214,7 +214,7 @@ smmap(p, uap, retval)
handle = NULL;
}
/*
* Map protections to MACH style
* Map current protections to MACH style
*/
prot = VM_PROT_NONE;
if (uap->prot & PROT_READ)
@ -652,12 +652,8 @@ vm_mmap(map, addr, size, prot, maxprot, flags, handle, foff)
/*
* Correct protection (default is VM_PROT_ALL).
* Note that we set the maximum protection. This may not be
* entirely correct. Maybe the maximum protection should be based
* on the object permissions where it makes sense (e.g. a vnode).
*
* XXX Changed my mind: leave max prot at VM_PROT_ALL.
* Changed again: indeed set maximum protection based on
* object permissions.
* entirely correct. The maximum protection is be based on
* the object permissions where it makes sense (e.g. a vnode).
*/
rv = vm_map_protect(map, *addr, *addr+size, prot, FALSE);
if (rv != KERN_SUCCESS) {