From faaaa53bdc6750c438887d44f99b60ad97ec74b4 Mon Sep 17 00:00:00 2001 From: Jike Song Date: Fri, 16 Dec 2016 10:51:05 +0800 Subject: [PATCH] drm/i915/gvt/kvmgt: check returned slot for gfn gfn_to_memslot() may return NULL if the gfn is mmio or invalid. A malicious user might input a bad gfn to panic the host if we don't check it. Signed-off-by: Jike Song Signed-off-by: Zhenyu Wang --- drivers/gpu/drm/i915/gvt/kvmgt.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 4ba196796846..8b3b071a535e 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -1137,6 +1137,10 @@ static int kvmgt_write_protect_add(unsigned long handle, u64 gfn) idx = srcu_read_lock(&kvm->srcu); slot = gfn_to_memslot(kvm, gfn); + if (!slot) { + srcu_read_unlock(&kvm->srcu, idx); + return -EINVAL; + } spin_lock(&kvm->mmu_lock); @@ -1167,6 +1171,10 @@ static int kvmgt_write_protect_remove(unsigned long handle, u64 gfn) idx = srcu_read_lock(&kvm->srcu); slot = gfn_to_memslot(kvm, gfn); + if (!slot) { + srcu_read_unlock(&kvm->srcu, idx); + return -EINVAL; + } spin_lock(&kvm->mmu_lock); -- 2.30.2