[PATCH] KVM: Use vmemdup_user()

From: Denis Efremov
Date: Wed Jun 03 2020 - 06:10:27 EST


Replace opencoded alloc and copy with vmemdup_user().

Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
---
Looks like these are the only places in KVM that are suitable for
vmemdup_user().

arch/x86/kvm/cpuid.c | 17 +++++++----------
virt/kvm/kvm_main.c | 19 ++++++++-----------
2 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 901cd1fdecd9..27438a2bdb62 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -182,17 +182,14 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
r = -E2BIG;
if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
goto out;
- r = -ENOMEM;
if (cpuid->nent) {
- cpuid_entries =
- vmalloc(array_size(sizeof(struct kvm_cpuid_entry),
- cpuid->nent));
- if (!cpuid_entries)
- goto out;
- r = -EFAULT;
- if (copy_from_user(cpuid_entries, entries,
- cpuid->nent * sizeof(struct kvm_cpuid_entry)))
+ cpuid_entries = vmemdup_user(entries,
+ array_size(sizeof(struct kvm_cpuid_entry),
+ cpuid->nent));
+ if (IS_ERR(cpuid_entries)) {
+ r = PTR_ERR(cpuid_entries);
goto out;
+ }
}
for (i = 0; i < cpuid->nent; i++) {
vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
@@ -212,8 +209,8 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
kvm_x86_ops.cpuid_update(vcpu);
r = kvm_update_cpuid(vcpu);

+ kvfree(cpuid_entries);
out:
- vfree(cpuid_entries);
return r;
}

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 731c1e517716..46a3743e95ff 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3722,21 +3722,18 @@ static long kvm_vm_ioctl(struct file *filp,
if (routing.flags)
goto out;
if (routing.nr) {
- r = -ENOMEM;
- entries = vmalloc(array_size(sizeof(*entries),
- routing.nr));
- if (!entries)
- goto out;
- r = -EFAULT;
urouting = argp;
- if (copy_from_user(entries, urouting->entries,
- routing.nr * sizeof(*entries)))
- goto out_free_irq_routing;
+ entries = vmemdup_user(urouting->entries,
+ array_size(sizeof(*entries),
+ routing.nr));
+ if (IS_ERR(entries)) {
+ r = PTR_ERR(entries);
+ goto out;
+ }
}
r = kvm_set_irq_routing(kvm, entries, routing.nr,
routing.flags);
-out_free_irq_routing:
- vfree(entries);
+ kvfree(entries);
break;
}
#endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */
--
2.26.2