From: Andi Kleen <ak@suse.de>
Date: Mon, 2 Jan 2006 23:07:28 +0000 (+0100)
Subject: [PATCH] Make sure interleave masks have at least one node set
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=8f493d797bc1fe470377adc9d8775845427e240e;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

[PATCH] Make sure interleave masks have at least one node set

Otherwise a bad mem policy system call can confuse the interleaving
code into referencing undefined nodes.

Originally reported by Doug Chapman

I was told it's CVE-2005-3358
(one has to love these security people - they make everything sound important)

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index bec88c81244e..72f402cc9c9a 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -161,6 +161,10 @@ static struct mempolicy *mpol_new(int mode, nodemask_t *nodes)
 	switch (mode) {
 	case MPOL_INTERLEAVE:
 		policy->v.nodes = *nodes;
+		if (nodes_weight(*nodes) == 0) {
+			kmem_cache_free(policy_cache, policy);
+			return ERR_PTR(-EINVAL);
+		}
 		break;
 	case MPOL_PREFERRED:
 		policy->v.preferred_node = first_node(*nodes);