KVM: Use memdup_user instead of kmalloc/copy_from_user

Switch to using memdup_user when possible. This makes code more
smaller and compact, and prevents errors.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 03042d6..0a646e2 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1309,12 +1309,11 @@ static int xen_hvm_config(struct kvm_vcpu *vcpu, u64 data)
        if (page_num >= blob_size)
                goto out;
        r = -ENOMEM;
-       page = kzalloc(PAGE_SIZE, GFP_KERNEL);
-       if (!page)
+       page = memdup_user(blob_addr + (page_num * PAGE_SIZE), PAGE_SIZE);
+       if (IS_ERR(page)) {
+               r = PTR_ERR(page);
                goto out;
-       r = -EFAULT;
-       if (copy_from_user(page, blob_addr + (page_num * PAGE_SIZE), PAGE_SIZE))
-               goto out_free;
+       }
        if (kvm_write_guest(kvm, page_addr, page, PAGE_SIZE))
                goto out_free;
        r = 0;
@@ -1988,15 +1987,12 @@ static int msr_io(struct kvm_vcpu *vcpu, struct kvm_msrs __user *user_msrs,
        if (msrs.nmsrs >= MAX_IO_MSRS)
                goto out;
 
-       r = -ENOMEM;
        size = sizeof(struct kvm_msr_entry) * msrs.nmsrs;
-       entries = kmalloc(size, GFP_KERNEL);
-       if (!entries)
+       entries = memdup_user(user_msrs->entries, size);
+       if (IS_ERR(entries)) {
+               r = PTR_ERR(entries);
                goto out;
-
-       r = -EFAULT;
-       if (copy_from_user(entries, user_msrs->entries, size))
-               goto out_free;
+       }
 
        r = n = __msr_io(vcpu, &msrs, entries, do_msr);
        if (r < 0)
@@ -2533,13 +2529,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                r = -EINVAL;
                if (!vcpu->arch.apic)
                        goto out;
-               u.lapic = kmalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
-               r = -ENOMEM;
-               if (!u.lapic)
-                       goto out;
-               r = -EFAULT;
-               if (copy_from_user(u.lapic, argp, sizeof(struct kvm_lapic_state)))
+               u.lapic = memdup_user(argp, sizeof(*u.lapic));
+               if (IS_ERR(u.lapic)) {
+                       r = PTR_ERR(u.lapic);
                        goto out;
+               }
+
                r = kvm_vcpu_ioctl_set_lapic(vcpu, u.lapic);
                if (r)
                        goto out;
@@ -2718,14 +2713,11 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                break;
        }
        case KVM_SET_XSAVE: {
-               u.xsave = kzalloc(sizeof(struct kvm_xsave), GFP_KERNEL);
-               r = -ENOMEM;
-               if (!u.xsave)
-                       break;
-
-               r = -EFAULT;
-               if (copy_from_user(u.xsave, argp, sizeof(struct kvm_xsave)))
-                       break;
+               u.xsave = memdup_user(argp, sizeof(*u.xsave));
+               if (IS_ERR(u.xsave)) {
+                       r = PTR_ERR(u.xsave);
+                       goto out;
+               }
 
                r = kvm_vcpu_ioctl_x86_set_xsave(vcpu, u.xsave);
                break;
@@ -2746,15 +2738,11 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                break;
        }
        case KVM_SET_XCRS: {
-               u.xcrs = kzalloc(sizeof(struct kvm_xcrs), GFP_KERNEL);
-               r = -ENOMEM;
-               if (!u.xcrs)
-                       break;
-
-               r = -EFAULT;
-               if (copy_from_user(u.xcrs, argp,
-                                  sizeof(struct kvm_xcrs)))
-                       break;
+               u.xcrs = memdup_user(argp, sizeof(*u.xcrs));
+               if (IS_ERR(u.xcrs)) {
+                       r = PTR_ERR(u.xcrs);
+                       goto out;
+               }
 
                r = kvm_vcpu_ioctl_x86_set_xcrs(vcpu, u.xcrs);
                break;
@@ -3190,14 +3178,14 @@ long kvm_arch_vm_ioctl(struct file *filp,
        }
        case KVM_GET_IRQCHIP: {
                /* 0: PIC master, 1: PIC slave, 2: IOAPIC */
-               struct kvm_irqchip *chip = kmalloc(sizeof(*chip), GFP_KERNEL);
+               struct kvm_irqchip *chip;
 
-               r = -ENOMEM;
-               if (!chip)
+               chip = memdup_user(argp, sizeof(*chip));
+               if (IS_ERR(chip)) {
+                       r = PTR_ERR(chip);
                        goto out;
-               r = -EFAULT;
-               if (copy_from_user(chip, argp, sizeof *chip))
-                       goto get_irqchip_out;
+               }
+
                r = -ENXIO;
                if (!irqchip_in_kernel(kvm))
                        goto get_irqchip_out;
@@ -3216,14 +3204,14 @@ long kvm_arch_vm_ioctl(struct file *filp,
        }
        case KVM_SET_IRQCHIP: {
                /* 0: PIC master, 1: PIC slave, 2: IOAPIC */
-               struct kvm_irqchip *chip = kmalloc(sizeof(*chip), GFP_KERNEL);
+               struct kvm_irqchip *chip;
 
-               r = -ENOMEM;
-               if (!chip)
+               chip = memdup_user(argp, sizeof(*chip));
+               if (IS_ERR(chip)) {
+                       r = PTR_ERR(chip);
                        goto out;
-               r = -EFAULT;
-               if (copy_from_user(chip, argp, sizeof *chip))
-                       goto set_irqchip_out;
+               }
+
                r = -ENXIO;
                if (!irqchip_in_kernel(kvm))
                        goto set_irqchip_out;

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a6e612f..d8bac07 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1821,12 +1821,11 @@ out_free1:
                struct kvm_regs *kvm_regs;
 
                r = -ENOMEM;
-               kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
-               if (!kvm_regs)
+               kvm_regs = memdup_user(argp, sizeof(*kvm_regs));
+               if (IS_ERR(kvm_regs)) {
+                       r = PTR_ERR(kvm_regs);
                        goto out;
-               r = -EFAULT;
-               if (copy_from_user(kvm_regs, argp, sizeof(struct kvm_regs)))
-                       goto out_free2;
+               }
                r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
                if (r)
                        goto out_free2;
@@ -1850,13 +1849,11 @@ out_free2:
                break;
        }
        case KVM_SET_SREGS: {
-               kvm_sregs = kmalloc(sizeof(struct kvm_sregs), GFP_KERNEL);
-               r = -ENOMEM;
-               if (!kvm_sregs)
-                       goto out;
-               r = -EFAULT;
-               if (copy_from_user(kvm_sregs, argp, sizeof(struct kvm_sregs)))
+               kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs));
+               if (IS_ERR(kvm_sregs)) {
+                       r = PTR_ERR(kvm_sregs);
                        goto out;
+               }
                r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
                if (r)
                        goto out;
@@ -1952,13 +1949,11 @@ out_free2:
                break;
        }
        case KVM_SET_FPU: {
-               fpu = kmalloc(sizeof(struct kvm_fpu), GFP_KERNEL);
-               r = -ENOMEM;
-               if (!fpu)
-                       goto out;
-               r = -EFAULT;
-               if (copy_from_user(fpu, argp, sizeof(struct kvm_fpu)))
+               fpu = memdup_user(argp, sizeof(*fpu));
+               if (IS_ERR(fpu)) {
+                       r = PTR_ERR(fpu);
                        goto out;
+               }
                r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
                if (r)
                        goto out;