[S390] KVM: Read buffer overflow

Check whether index is within bounds before testing the element.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
index 36678835034d..0ef81d6776e9 100644
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -169,7 +169,7 @@ static int __sigp_set_prefix(struct kvm_vcpu *vcpu, u16 cpu_addr, u32 address,
                              unsigned long *reg)
 {
         struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
-        struct kvm_s390_local_interrupt *li;
+        struct kvm_s390_local_interrupt *li = NULL;
         struct kvm_s390_interrupt_info *inti;
         int rc;
         u8 tmp;
@@ -189,9 +189,10 @@ static int __sigp_set_prefix(struct kvm_vcpu *vcpu, u16 cpu_addr, u32 address,
                 return 2; /* busy */
 
         spin_lock(&fi->lock);
-        li = fi->local_int[cpu_addr];
+        if (cpu_addr < KVM_MAX_VCPUS)
+                li = fi->local_int[cpu_addr];
 
-        if ((cpu_addr >= KVM_MAX_VCPUS) || (li == NULL)) {
+        if (li == NULL) {
                 rc = 1; /* incorrect state */
                 *reg &= SIGP_STAT_INCORRECT_STATE;
                 kfree(inti);