linux-kernel - Virt: Kvm - Fix possible ERR

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Date:   Tue, 20 Sep 2016 12:20:10 +0530
From:   Shailendra Verma <shailendra.v@...sung.com>
To:     Gleb Natapov <gleb@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        Shailendra Verma <shailendra.v@...sung.com>,
        Ravikant Sharma <ravikant.s2@...sung.com>
Cc:     linux-kernel@...r.kernel.org, vidushi.koul@...sung.com
Subject: Virt: Kvm - Fix possible ERR_PTR() dereferencing.

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@...sung.com>
Signed-off-by: Shailendra Verma <shailendra.v@...sung.com>
---
 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