Virt: Kvm - Fix possible ERR_PTR() dereferencing.

From: Shailendra Verma
Date: Tue Sep 20 2016 - 02:50:37 EST


This is of course wrong to call kfree() if memdup_user() fails,
no memory was allocated and the error in the error-valued pointer
should be returned.

Reviewed-by: Ravikant Sharma <ravikant.s2@xxxxxxxxxxx>
Signed-off-by: Shailendra Verma <shailendra.v@xxxxxxxxxxx>
---
virt/kvm/kvm_main.c | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 484079e..e3a0653 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2398,10 +2398,8 @@ out_free1:

r = -ENOMEM;
kvm_regs = memdup_user(argp, sizeof(*kvm_regs));
- if (IS_ERR(kvm_regs)) {
- r = PTR_ERR(kvm_regs);
- goto out;
- }
+ if (IS_ERR(kvm_regs))
+ return PTR_ERR(kvm_regs);
r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
kfree(kvm_regs);
break;
@@ -2422,11 +2420,8 @@ out_free1:
}
case KVM_SET_SREGS: {
kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs));
- if (IS_ERR(kvm_sregs)) {
- r = PTR_ERR(kvm_sregs);
- kvm_sregs = NULL;
- goto out;
- }
+ if (IS_ERR(kvm_sregs))
+ return PTR_ERR(kvm_sregs);
r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
break;
}
@@ -2514,11 +2509,8 @@ out_free1:
}
case KVM_SET_FPU: {
fpu = memdup_user(argp, sizeof(*fpu));
- if (IS_ERR(fpu)) {
- r = PTR_ERR(fpu);
- fpu = NULL;
- goto out;
- }
+ if (IS_ERR(fpu))
+ return PTR_ERR(fpu);
r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
break;
}
--
1.9.1