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FAILED: patch "[PATCH] KVM: x86: Copy filter arg outside" failed to apply to 5.15-stable tree

PATCH [email protected] 1 participant 1 message Oct 26, 2022

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Stable branch x86 KVM x86
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The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Possible dependencies:

2e3272bc1790 ("KVM: x86: Copy filter arg outside kvm_vm_ioctl_set_msr_filter()") cf5029d5dd7c ("KVM: x86: Protect the unused bits in MSR exiting flags")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2e3272bc1790825c43d2c39690bf2836b81c6d36 Mon Sep 17 00:00:00 2001
From: Alexander Graf <[email protected]>
Date: Mon, 17 Oct 2022 20:45:40 +0200
Subject: [PATCH] KVM: x86: Copy filter arg outside
kvm_vm_ioctl_set_msr_filter()

In the next patch we want to introduce a second caller to set_msr_filter() which constructs its own filter list on the stack. Refactor the original function so it takes it as argument instead of reading it through copy_from_user().

Signed-off-by Alexander Graf <[email protected]>

Message-Id: <[email protected]>

Cc [email protected]
Signed-off-by Paolo Bonzini <[email protected]>
arch/x86/kvm/x86.c +17 -14
index 4bd5f8a751de..78f779f0264b 100644
@@ -6442,26 +6442,22 @@ static int kvm_add_msr_filter(struct kvm_x86_msr_filter *msr_filter,
 	return 0;
 }
 
-static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm, void __user *argp)
+static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm,
+				       struct kvm_msr_filter *filter)
 {
-	struct kvm_msr_filter __user *user_msr_filter = argp;
 	struct kvm_x86_msr_filter *new_filter, *old_filter;
-	struct kvm_msr_filter filter;
 	bool default_allow;
 	bool empty = true;
 	int r = 0;
 	u32 i;
 
-	if (copy_from_user(&filter, user_msr_filter, sizeof(filter)))
-		return -EFAULT;
-
-	if (filter.flags & ~KVM_MSR_FILTER_DEFAULT_DENY)
+	if (filter->flags & ~KVM_MSR_FILTER_DEFAULT_DENY)
 		return -EINVAL;
 
-	for (i = 0; i < ARRAY_SIZE(filter.ranges); i++)
-		empty &= !filter.ranges[i].nmsrs;
+	for (i = 0; i < ARRAY_SIZE(filter->ranges); i++)
+		empty &= !filter->ranges[i].nmsrs;
 
-	default_allow = !(filter.flags & KVM_MSR_FILTER_DEFAULT_DENY);
+	default_allow = !(filter->flags & KVM_MSR_FILTER_DEFAULT_DENY);
 	if (empty && !default_allow)
 		return -EINVAL;
 

@@ -6469,8 +6465,8 @@ static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm, void __user *argp)
 	if (!new_filter)
 		return -ENOMEM;
 
-	for (i = 0; i < ARRAY_SIZE(filter.ranges); i++) {
-		r = kvm_add_msr_filter(new_filter, &filter.ranges[i]);
+	for (i = 0; i < ARRAY_SIZE(filter->ranges); i++) {
+		r = kvm_add_msr_filter(new_filter, &filter->ranges[i]);
 		if (r) {
 			kvm_free_msr_filter(new_filter);
 			return r;

@@ -6915,9 +6911,16 @@ long kvm_arch_vm_ioctl(struct file *filp,
 	case KVM_SET_PMU_EVENT_FILTER:
 		r = kvm_vm_ioctl_set_pmu_event_filter(kvm, argp);
 		break;
-	case KVM_X86_SET_MSR_FILTER:
-		r = kvm_vm_ioctl_set_msr_filter(kvm, argp);
+	case KVM_X86_SET_MSR_FILTER: {
+		struct kvm_msr_filter __user *user_msr_filter = argp;
+		struct kvm_msr_filter filter;
+
+		if (copy_from_user(&filter, user_msr_filter, sizeof(filter)))
+			return -EFAULT;
+
+		r = kvm_vm_ioctl_set_msr_filter(kvm, &filter);
 		break;
+	}
 	default:
 		r = -ENOTTY;
 	}