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Verify that access to the given address is allowed from user-space.

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Discussed with: rwatson@
This commit is contained in:
Alan Cox 2005-10-22 20:02:59 +00:00
parent f6d8983846
commit 0a5a219830
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=151559
1 changed files with 8 additions and 1 deletions
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9
sys/kern/uipc_cow.c
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@ -50,6 +50,7 @@ __FBSDID("$FreeBSD$");
#include <sys/uio.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
@ -104,15 +105,21 @@ socow_setup(struct mbuf *m0, struct uio *uio)
struct vm_map *map;
vm_offset_t offset, uva;
socow_stats.attempted++;
vmspace = curproc->p_vmspace;
map = &vmspace->vm_map;
uva = (vm_offset_t) uio->uio_iov->iov_base;
offset = uva & PAGE_MASK;
/*
* Verify that access to the given address is allowed from user-space.
*/
if (vm_fault_quick((caddr_t)uva, VM_PROT_READ) < 0)
return (0);
/*
* verify page is mapped & not already wired for i/o
*/
socow_stats.attempted++;
pa=pmap_extract(map->pmap, uva);
if(!pa) {
socow_stats.fail_not_mapped++;