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| author | Paolo Bonzini <pbonzini@redhat.com> | 2016-06-01 15:09:22 +0300 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2016-06-02 18:38:50 +0300 |
| commit | f8c1b85b2523da59c8c03ea94e9d0fac04155943 (patch) | |
| tree | 4d421bea0523fcdc0cfa80ad8a4df84128912505 | |
| parent | c622a3c21ede892e370b56e1ceb9eb28f8bbda6b (diff) | |
| download | linux-f8c1b85b2523da59c8c03ea94e9d0fac04155943.tar.xz | |
KVM: x86: avoid vmalloc(0) in the KVM_SET_CPUID
This causes an ugly dmesg splat. Beautified syzkaller testcase:
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <linux/kvm.h>
long r[8];
int main()
{
struct kvm_irq_routing ir = { 0 };
r[2] = open("/dev/kvm", O_RDWR);
r[3] = ioctl(r[2], KVM_CREATE_VM, 0);
r[4] = ioctl(r[3], KVM_SET_GSI_ROUTING, &ir);
return 0;
}
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
| -rw-r--r-- | virt/kvm/kvm_main.c | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 37af23052470..02e98f3131bd 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2935,7 +2935,7 @@ static long kvm_vm_ioctl(struct file *filp, case KVM_SET_GSI_ROUTING: { struct kvm_irq_routing routing; struct kvm_irq_routing __user *urouting; - struct kvm_irq_routing_entry *entries; + struct kvm_irq_routing_entry *entries = NULL; r = -EFAULT; if (copy_from_user(&routing, argp, sizeof(routing))) @@ -2945,15 +2945,17 @@ static long kvm_vm_ioctl(struct file *filp, goto out; if (routing.flags) goto out; - r = -ENOMEM; - entries = vmalloc(routing.nr * sizeof(*entries)); - if (!entries) - goto out; - r = -EFAULT; - urouting = argp; - if (copy_from_user(entries, urouting->entries, - routing.nr * sizeof(*entries))) - goto out_free_irq_routing; + if (routing.nr) { + r = -ENOMEM; + entries = vmalloc(routing.nr * sizeof(*entries)); + if (!entries) + goto out; + r = -EFAULT; + urouting = argp; + if (copy_from_user(entries, urouting->entries, + routing.nr * sizeof(*entries))) + goto out_free_irq_routing; + } r = kvm_set_irq_routing(kvm, entries, routing.nr, routing.flags); out_free_irq_routing: |