From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Cherian Subject: Re: [PATCH] ACPI / CPPC: Fix negative array index read in cppc_set_perf Date: Fri, 15 Dec 2017 23:48:31 +0530 Message-ID: References: <20171213224541.GA31477@embeddedor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-dm3nam03on0079.outbound.protection.outlook.com ([104.47.41.79]:8416 "EHLO NAM03-DM3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755419AbdLOSSh (ORCPT ); Fri, 15 Dec 2017 13:18:37 -0500 In-Reply-To: <20171213224541.GA31477@embeddedor.com> Content-Language: en-US Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Gustavo A. R. Silva" , "Rafael J. Wysocki" , Len Brown , George Cherian Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org On Thursday 14 December 2017 04:15 AM, Gustavo A. R. Silva wrote: > If pcc_ss_id is less than 0, there is a negative array index read > before verifying pcc_ss_id is not a negative value. > > Fix this by removing the code that triggers this issue. > > Notice that this code is already properly placed after the check > on pcc_ss_id at line 1182: pcc_ss_data = pcc_data[pcc_ss_id]; > > Addresses-Coverity-ID: 1426090 ("Negative array index read") > Fixes: 1ecbd7170d65 ("ACPI / CPPC: Fix KASAN global out of bounds warning") Reviewed-by: George Cherian > Signed-off-by: Gustavo A. R. Silva > --- > drivers/acpi/cppc_acpi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c > index 30e84cc..06ea474 100644 > --- a/drivers/acpi/cppc_acpi.c > +++ b/drivers/acpi/cppc_acpi.c > @@ -1171,7 +1171,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls) > struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu); > struct cpc_register_resource *desired_reg; > int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu); > - struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id]; > + struct cppc_pcc_data *pcc_ss_data; > int ret = 0; > > if (!cpc_desc || pcc_ss_id < 0) {