From: Tianyu Li <tianyu.li@xxxxxxx> [ Upstream commit 000eca5d044d1ee23b4ca311793cf3fc528da6c6 ] When user specified more nodes than supported, get_nodes will access nmask array out of bounds. Link: https://lkml.kernel.org/r/20220601093211.2970565-1-tianyu.li@xxxxxxx Fixes: e130242dc351 ("mm: simplify compat numa syscalls") Signed-off-by: Tianyu Li <tianyu.li@xxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- mm/mempolicy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index b27e8d71cda3..c1ccc89845f4 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1387,7 +1387,7 @@ static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask, unsigned long bits = min_t(unsigned long, maxnode, BITS_PER_LONG); unsigned long t; - if (get_bitmap(&t, &nmask[maxnode / BITS_PER_LONG], bits)) + if (get_bitmap(&t, &nmask[(maxnode - 1) / BITS_PER_LONG], bits)) return -EFAULT; if (maxnode - bits >= MAX_NUMNODES) { -- 2.35.1
