From 8c4976772d9b5858b8b456e84783e089c6cfa66e Mon Sep 17 00:00:00 2001 From: Philipp Stanner Date: Thu, 2 Nov 2023 19:15:25 +0100 Subject: [PATCH] KVM: s390: Harden copying of userspace-array against overflow guestdbg.c utilizes memdup_user() to copy a userspace array. This, currently, does not check for an overflow. Use the new wrapper memdup_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 Signed-off-by: Philipp Stanner Acked-by: Claudio Imbrenda Acked-by: Christian Borntraeger Link: https://lore.kernel.org/r/20231102181526.43279-3-pstanner@redhat.com [sean: call out that KVM pre-checks the number of entries] Signed-off-by: Sean Christopherson --- arch/s390/kvm/guestdbg.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/guestdbg.c b/arch/s390/kvm/guestdbg.c index 3765c4223bf9..80879fc73c90 100644 --- a/arch/s390/kvm/guestdbg.c +++ b/arch/s390/kvm/guestdbg.c @@ -213,8 +213,8 @@ int kvm_s390_import_bp_data(struct kvm_vcpu *vcpu, else if (dbg->arch.nr_hw_bp > MAX_BP_COUNT) return -EINVAL; - bp_data = memdup_user(dbg->arch.hw_bp, - sizeof(*bp_data) * dbg->arch.nr_hw_bp); + bp_data = memdup_array_user(dbg->arch.hw_bp, dbg->arch.nr_hw_bp, + sizeof(*bp_data)); if (IS_ERR(bp_data)) return PTR_ERR(bp_data);