Commit 83a35114 authored by Rusty Russell's avatar Rusty Russell Committed by Linus Torvalds

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: default avatarRusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3cfd4ba7
...@@ -173,7 +173,7 @@ static void unmap_switcher(void) ...@@ -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);
} }
/* /*
......
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