Messages in this thread | | | Date | Mon, 10 Oct 2022 17:15:40 +0300 | From | Dan Carpenter <> | Subject | [kbuild] arch/x86/kvm/x86.c:4988 kvm_arch_tsc_set_attr() warn: check for integer overflow 'offset' |
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tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 493ffd6605b2d3d4dc7008ab927dba319f36671f commit: 828ca89628bfcb1b8f27535025f69dd00eb55207 KVM: x86: Expose TSC offset controls to userspace config: x86_64-randconfig-m001-20221010 compiler: gcc-11 (Debian 11.3.0-5) 11.3.0
If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@intel.com> | Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
smatch warnings: arch/x86/kvm/x86.c:4988 kvm_arch_tsc_set_attr() warn: check for integer overflow 'offset'
vim +/offset +4988 arch/x86/kvm/x86.c
828ca89628bfcb Oliver Upton 2021-09-16 4962 static int kvm_arch_tsc_set_attr(struct kvm_vcpu *vcpu, 828ca89628bfcb Oliver Upton 2021-09-16 4963 struct kvm_device_attr *attr) 828ca89628bfcb Oliver Upton 2021-09-16 4964 { 828ca89628bfcb Oliver Upton 2021-09-16 4965 u64 __user *uaddr = (u64 __user *)(unsigned long)attr->addr; 828ca89628bfcb Oliver Upton 2021-09-16 4966 struct kvm *kvm = vcpu->kvm; 828ca89628bfcb Oliver Upton 2021-09-16 4967 int r; 828ca89628bfcb Oliver Upton 2021-09-16 4968 828ca89628bfcb Oliver Upton 2021-09-16 4969 if ((u64)(unsigned long)uaddr != attr->addr) 828ca89628bfcb Oliver Upton 2021-09-16 4970 return -EFAULT; 828ca89628bfcb Oliver Upton 2021-09-16 4971 828ca89628bfcb Oliver Upton 2021-09-16 4972 switch (attr->attr) { 828ca89628bfcb Oliver Upton 2021-09-16 4973 case KVM_VCPU_TSC_OFFSET: { 828ca89628bfcb Oliver Upton 2021-09-16 4974 u64 offset, tsc, ns; 828ca89628bfcb Oliver Upton 2021-09-16 4975 unsigned long flags; 828ca89628bfcb Oliver Upton 2021-09-16 4976 bool matched; 828ca89628bfcb Oliver Upton 2021-09-16 4977 828ca89628bfcb Oliver Upton 2021-09-16 4978 r = -EFAULT; 828ca89628bfcb Oliver Upton 2021-09-16 4979 if (get_user(offset, uaddr)) 828ca89628bfcb Oliver Upton 2021-09-16 4980 break; 828ca89628bfcb Oliver Upton 2021-09-16 4981 828ca89628bfcb Oliver Upton 2021-09-16 4982 raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); 828ca89628bfcb Oliver Upton 2021-09-16 4983 828ca89628bfcb Oliver Upton 2021-09-16 4984 matched = (vcpu->arch.virtual_tsc_khz && 828ca89628bfcb Oliver Upton 2021-09-16 4985 kvm->arch.last_tsc_khz == vcpu->arch.virtual_tsc_khz && 828ca89628bfcb Oliver Upton 2021-09-16 4986 kvm->arch.last_tsc_offset == offset); 828ca89628bfcb Oliver Upton 2021-09-16 4987 828ca89628bfcb Oliver Upton 2021-09-16 @4988 tsc = kvm_scale_tsc(vcpu, rdtsc(), vcpu->arch.l1_tsc_scaling_ratio) + offset;
Smatch hates obvious user triggerable integer overflows... No checking on offset.
828ca89628bfcb Oliver Upton 2021-09-16 4989 ns = get_kvmclock_base_ns(); 828ca89628bfcb Oliver Upton 2021-09-16 4990 828ca89628bfcb Oliver Upton 2021-09-16 4991 __kvm_synchronize_tsc(vcpu, offset, tsc, ns, matched); 828ca89628bfcb Oliver Upton 2021-09-16 4992 raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags); 828ca89628bfcb Oliver Upton 2021-09-16 4993 828ca89628bfcb Oliver Upton 2021-09-16 4994 r = 0; 828ca89628bfcb Oliver Upton 2021-09-16 4995 break; 828ca89628bfcb Oliver Upton 2021-09-16 4996 } 828ca89628bfcb Oliver Upton 2021-09-16 4997 default: 828ca89628bfcb Oliver Upton 2021-09-16 4998 r = -ENXIO; 828ca89628bfcb Oliver Upton 2021-09-16 4999 } 828ca89628bfcb Oliver Upton 2021-09-16 5000 828ca89628bfcb Oliver Upton 2021-09-16 5001 return r; 828ca89628bfcb Oliver Upton 2021-09-16 5002 }
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