Messages in this thread Patch in this message | | | From | Yang Li <> | Subject | [PATCH] KVM: x86: Fix potential memory access error | Date | Wed, 31 Mar 2021 17:15:22 +0800 |
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Using __set_bit() to set a bit in an integer is not a good idea, since the function expects an unsigned long as argument, which can be 64bit wide. Coverity reports this problem as
High:Out-of-bounds access(INCOMPATIBLE_CAST) CWE119: Out-of-bounds access to a scalar Pointer "&vcpu->arch.regs_avail" points to an object whose effective type is "unsigned int" (32 bits, unsigned) but is dereferenced as a wider "unsigned long" (64 bits, unsigned). This may lead to memory corruption.
/home/heyuan.shy/git-repo/linux/arch/x86/kvm/kvm_cache_regs.h: kvm_register_is_available
Just use BIT instead.
Reported-by: Abaci Robot <abaci@linux.alibaba.com> Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> --- arch/x86/kvm/kvm_cache_regs.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index 2e11da2..cfa45d88 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -52,14 +52,14 @@ static inline bool kvm_register_is_dirty(struct kvm_vcpu *vcpu, static inline void kvm_register_mark_available(struct kvm_vcpu *vcpu, enum kvm_reg reg) { - __set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); + vcpu->arch.regs_avail |= BIT(reg); } static inline void kvm_register_mark_dirty(struct kvm_vcpu *vcpu, enum kvm_reg reg) { - __set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); - __set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty); + vcpu->arch.regs_avail |= BIT(reg); + vcpu->arch.regs_dirty |= BIT(reg); } static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu, int reg) -- 1.8.3.1
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