Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751820AbdH2JGw (ORCPT ); Tue, 29 Aug 2017 05:06:52 -0400 Received: from terminus.zytor.com ([65.50.211.136]:55383 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751276AbdH2JGt (ORCPT ); Tue, 29 Aug 2017 05:06:49 -0400 Date: Tue, 29 Aug 2017 02:03:43 -0700 From: tip-bot for Borislav Petkov Message-ID: Cc: hpa@zytor.com, tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org, bp@suse.de, dan.carpenter@oracle.com Reply-To: dan.carpenter@oracle.com, bp@suse.de, mingo@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@zytor.com In-Reply-To: <20170825100456.n236w3jebteokfd6@pd.tnic> References: <20170825100456.n236w3jebteokfd6@pd.tnic> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/microcode] x86/microcode/intel: Improve microcode patches saving flow Git-Commit-ID: aa78c1ccfab6018289bc2bfd0092d516d0a49ec5 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3135 Lines: 99 Commit-ID: aa78c1ccfab6018289bc2bfd0092d516d0a49ec5 Gitweb: http://git.kernel.org/tip/aa78c1ccfab6018289bc2bfd0092d516d0a49ec5 Author: Borislav Petkov AuthorDate: Fri, 25 Aug 2017 12:04:56 +0200 Committer: Thomas Gleixner CommitDate: Tue, 29 Aug 2017 10:59:28 +0200 x86/microcode/intel: Improve microcode patches saving flow Avoid potentially dereferencing a NULL pointer when saving a microcode patch for early loading on the application processors. While at it, drop the IS_ERR() checking in favor of simpler, NULL-ptr checks which are sufficient and rename __alloc_microcode_buf() to memdup_patch() to more precisely denote what it does. No functionality change. Reported-by: Dan Carpenter Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: kernel-janitors@vger.kernel.org Link: http://lkml.kernel.org/r/20170825100456.n236w3jebteokfd6@pd.tnic --- arch/x86/kernel/cpu/microcode/intel.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index 59edbe9..8f7a9bb 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -146,18 +146,18 @@ static bool microcode_matches(struct microcode_header_intel *mc_header, return false; } -static struct ucode_patch *__alloc_microcode_buf(void *data, unsigned int size) +static struct ucode_patch *memdup_patch(void *data, unsigned int size) { struct ucode_patch *p; p = kzalloc(sizeof(struct ucode_patch), GFP_KERNEL); if (!p) - return ERR_PTR(-ENOMEM); + return NULL; p->data = kmemdup(data, size, GFP_KERNEL); if (!p->data) { kfree(p); - return ERR_PTR(-ENOMEM); + return NULL; } return p; @@ -183,8 +183,8 @@ static void save_microcode_patch(void *data, unsigned int size) if (mc_hdr->rev <= mc_saved_hdr->rev) continue; - p = __alloc_microcode_buf(data, size); - if (IS_ERR(p)) + p = memdup_patch(data, size); + if (!p) pr_err("Error allocating buffer %p\n", data); else list_replace(&iter->plist, &p->plist); @@ -196,24 +196,25 @@ static void save_microcode_patch(void *data, unsigned int size) * newly found. */ if (!prev_found) { - p = __alloc_microcode_buf(data, size); - if (IS_ERR(p)) + p = memdup_patch(data, size); + if (!p) pr_err("Error allocating buffer for %p\n", data); else list_add_tail(&p->plist, µcode_cache); } + if (!p) + return; + /* * Save for early loading. On 32-bit, that needs to be a physical * address as the APs are running from physical addresses, before * paging has been enabled. */ - if (p) { - if (IS_ENABLED(CONFIG_X86_32)) - intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data); - else - intel_ucode_patch = p->data; - } + if (IS_ENABLED(CONFIG_X86_32)) + intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data); + else + intel_ucode_patch = p->data; } static int microcode_sanity_check(void *mc, int print_err)