From 1f829359c8c37f77a340575957686ca8c4bca317 Mon Sep 17 00:00:00 2001
From: Philipp Stanner <pstanner@redhat.com>
Date: Thu, 2 Nov 2023 19:15:26 +0100
Subject: [PATCH] KVM: Harden copying of userspace-array against overflow
kvm_main.c utilizes vmemdup_user() and array_size() to copy a userspace
array. Currently, this does not check for an overflow.
Use the new wrapper vmemdup_array_user() to copy the array more safely.
Note, KVM explicitly checks the number of entries before duplicating the
array, i.e. adding the overflow check should be a glorified nop.
Suggested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Link: https://lore.kernel.org/r/20231102181526.43279-4-pstanner@redhat.com
[sean: call out that KVM pre-checks the number of entries]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
virt/kvm/kvm_main.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b744eddecbc07..e76d49daa4701 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5262,9 +5262,8 @@ static long kvm_vm_ioctl(struct file *filp,
goto out;
if (routing.nr) {
urouting = argp;
- entries = vmemdup_user(urouting->entries,
- array_size(sizeof(*entries),
- routing.nr));
+ entries = vmemdup_array_user(urouting->entries,
+ routing.nr, sizeof(*entries));
if (IS_ERR(entries)) {
r = PTR_ERR(entries);
goto out;
--
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