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authorPaolo Bonzini <pbonzini@redhat.com>2016-06-01 14:09:22 +0200
committerRadim Krčmář <rkrcmar@redhat.com>2016-06-02 17:38:50 +0200
commitf8c1b85b2523da59c8c03ea94e9d0fac04155943 (patch)
tree4d421bea0523fcdc0cfa80ad8a4df84128912505 /virt
parentc622a3c21ede892e370b56e1ceb9eb28f8bbda6b (diff)
downloadlinux-f8c1b85b2523da59c8c03ea94e9d0fac04155943.tar.gz
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>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c22
1 files changed, 12 insertions, 10 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 37af230..02e98f3 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: