lguest: fix out-by-one error in address checking.

This bug has been there since day 1; addresses in the top guest physical
page weren't considered valid.  You could map that page (the check in
check_gpte() is correct), but if a guest tried to put a pagetable there
we'd check that address manually when walking it, and kill the guest.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rusty Russell 2015-05-27 10:59:26 +09:30 committed by Linus Torvalds
parent 3cfd4ba7d3
commit 83a35114d0
1 changed files with 1 additions and 1 deletions

View File

@ -173,7 +173,7 @@ static void unmap_switcher(void)
bool lguest_address_ok(const struct lguest *lg, bool lguest_address_ok(const struct lguest *lg,
unsigned long addr, unsigned long len) unsigned long addr, unsigned long len)
{ {
return (addr+len) / PAGE_SIZE < lg->pfn_limit && (addr+len >= addr); return addr+len <= lg->pfn_limit * PAGE_SIZE && (addr+len >= addr);
} }
/* /*