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[34.168.104.7]) by smtp.gmail.com with ESMTPSA id q18-20020a17090311d200b00188f07c9eedsm7601657plh.176.2022.12.19.12.56.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Dec 2022 12:56:51 -0800 (PST) Date: Mon, 19 Dec 2022 20:56:48 +0000 From: Sean Christopherson To: coverity-bot Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Borislav Petkov , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , Paolo Bonzini , Sean Christopherson , kvm@vger.kernel.org, Dave Hansen , "Gustavo A. R. Silva" , linux-next@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: Coverity: handle_vmclear(): Error handling issues Message-ID: References: <202212010825.C23022D@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202212010825.C23022D@keescook> Precedence: bulk List-ID: X-Mailing-List: linux-next@vger.kernel.org On Thu, Dec 01, 2022, coverity-bot wrote: > Hello! > > This is an experimental semi-automated report about issues detected by > Coverity from a scan of next-20221201 as part of the linux-next scan project: > https://scan.coverity.com/projects/linux-next-weekly-scan > > You're getting this email because you were associated with the identified > lines of code (noted below) that were touched by commits: > > Fri Dec 14 17:59:46 2018 +0100 > 55d2375e58a6 ("KVM: nVMX: Move nested code to dedicated files") > > Coverity reported the following: > > *** CID 1527765: Error handling issues (CHECKED_RETURN) > arch/x86/kvm/vmx/nested.c:5269 in handle_vmclear() > 5263 */ > 5264 if (likely(!guest_cpuid_has_evmcs(vcpu) || > 5265 !evmptr_is_valid(nested_get_evmptr(vcpu)))) { > 5266 if (vmptr == vmx->nested.current_vmptr) > 5267 nested_release_vmcs12(vcpu); > 5268 > vvv CID 1527765: Error handling issues (CHECKED_RETURN) > vvv Calling "kvm_vcpu_write_guest" without checking return value (as is done elsewhere 7 out of 8 times). > 5269 kvm_vcpu_write_guest(vcpu, > 5270 vmptr + offsetof(struct vmcs12, > 5271 launch_state), > 5272 &zero, sizeof(zero)); > 5273 } else if (vmx->nested.hv_evmcs && vmptr == vmx->nested.hv_evmcs_vmptr) { > 5274 nested_release_evmcs(vcpu); > > If this is a false positive, please let us know so we can mark it as > such, or teach the Coverity rules to be smarter. If not, please make > sure fixes get into linux-next. :) For patches fixing this, please > include these lines (but double-check the "Fixes" first): > > Reported-by: coverity-bot > Addresses-Coverity-ID: 1527765 ("Error handling issues") > Fixes: 55d2375e58a6 ("KVM: nVMX: Move nested code to dedicated files") Nit on the bot, if it's going to provide a Fixes without human verification, then it should probably try to bisect (which I realize could get quite nasty). Both this VMCLEAR issue and the SMM issue report bogus Fixes due to code movement. If the blamed commit on this won't hadn't been so obviously wrong I likely would have copy+pasted without ever verifying. Maybe just omit the Fixes entirely and rely on the above "touched by commits" to provide the developer with the hint?