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xen-gntdev: prevent using UNMAP_NOTIFY_CLEAR_BYTE on read-only mappings 

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Daniel De Graaf 2011-02-09 18:15:50 -05:00 committed by Konrad Rzeszutek Wilk
parent 12996fc38a
commit 9960be970c
1 changed files with 9 additions and 1 deletions
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10
drivers/xen/gntdev.c
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@ -294,7 +294,9 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
if (pgno >= offset && pgno < offset + pages && use_ptemod) {
void __user *tmp;
tmp = map->vma->vm_start + map->notify.addr;
copy_to_user(tmp, &err, 1);
err = copy_to_user(tmp, &err, 1);
if (err)
return err;
map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
} else if (pgno >= offset && pgno < offset + pages) {
uint8_t *tmp = kmap(map->pages[pgno]);
@ -599,6 +601,12 @@ static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
goto unlock_out;
found:
if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
(map->flags & GNTMAP_readonly)) {
rc = -EINVAL;
goto unlock_out;
}
map->notify.flags = op.action;
map->notify.addr = op.index - (map->index << PAGE_SHIFT);
map->notify.event = op.event_channel_port;