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Fix some serious problems with limits checking in the sbrk(2)/brk(2)

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code.
Reviewed by:	bde
This commit is contained in:
John Dyson 1996-06-25 00:36:46 +00:00
parent 830b0d3039
commit f0e2953e5e
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=16679
1 changed files with 25 additions and 13 deletions
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38
sys/vm/vm_unix.c
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@ -38,7 +38,7 @@
* from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
*
* @(#)vm_unix.c 8.1 (Berkeley) 6/11/93
* $Id: vm_unix.c,v 1.9 1995/12/07 12:48:29 davidg Exp $
* $Id: vm_unix.c,v 1.10 1996/01/19 04:00:27 dyson Exp $
*/
/*
@ -72,33 +72,45 @@ obreak(p, uap, retval)
int *retval;
{
register struct vmspace *vm = p->p_vmspace;
vm_offset_t new, old;
vm_offset_t new, old, base;
int rv;
register int diff;
old = (vm_offset_t) vm->vm_daddr;
base = round_page((vm_offset_t) vm->vm_daddr);
new = round_page(uap->nsize);
if ((int) (new - old) > p->p_rlimit[RLIMIT_DATA].rlim_cur)
return (ENOMEM);
old = round_page(old + ctob(vm->vm_dsize));
diff = new - old;
if (diff > 0) {
if (new > base) {
if ((new - base) > (unsigned) p->p_rlimit[RLIMIT_DATA].rlim_cur)
return ENOMEM;
if (new >= VM_MAXUSER_ADDRESS)
return (ENOMEM);
} else if (new < base) {
/*
* This is simply an invalid value. If someone wants to
* do fancy address space manipulations, mmap and munmap
* can do most of what the user would want.
*/
return EINVAL;
}
old = base + ctob(vm->vm_dsize);
if (new > old) {
vm_size_t diff;
if (swap_pager_full) {
return (ENOMEM);
}
diff = new - old;
rv = vm_map_find(&vm->vm_map, NULL, 0, &old, diff, FALSE,
VM_PROT_ALL, VM_PROT_ALL, 0);
if (rv != KERN_SUCCESS) {
return (ENOMEM);
}
vm->vm_dsize += btoc(diff);
} else if (diff < 0) {
diff = -diff;
rv = vm_map_remove(&vm->vm_map, new, new + diff);
} else if (new < old) {
rv = vm_map_remove(&vm->vm_map, new, old);
if (rv != KERN_SUCCESS) {
return (ENOMEM);
}
vm->vm_dsize -= btoc(diff);
vm->vm_dsize -= btoc(old - new);
}
return (0);
}