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KVM: Use memdup_user instead of kmalloc/copy_from_user
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Switch to using memdup_user when possible. This makes code more
smaller and compact, and prevents errors.

Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Avi Kivity <[email protected]>
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@sashalevin @avikivity
sashalevin authored and avikivity committed Dec 27, 2011
1 parent cdfca7b commit ff5c2c0
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Showing 2 changed files with 47 additions and 64 deletions.
82 changes: 35 additions & 47 deletions arch/x86/kvm/x86.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand Down
29 changes: 12 additions & 17 deletions virt/kvm/kvm_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1821,12 +1821,11 @@ static long kvm_vcpu_ioctl(struct file *filp,
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;
Expand All @@ -1850,13 +1849,11 @@ static long kvm_vcpu_ioctl(struct file *filp,
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;
Expand Down Expand Up @@ -1952,13 +1949,11 @@ static long kvm_vcpu_ioctl(struct file *filp,
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;
Expand Down

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