From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2800EC43381 for ; Wed, 27 Mar 2019 14:53:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAC022082F for ; Wed, 27 Mar 2019 14:53:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="BBpgm1Nl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728836AbfC0Oxt (ORCPT ); Wed, 27 Mar 2019 10:53:49 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:46298 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728616AbfC0Oxt (ORCPT ); Wed, 27 Mar 2019 10:53:49 -0400 Received: by mail-pf1-f196.google.com with SMTP id 9so9804922pfj.13 for ; Wed, 27 Mar 2019 07:53:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=LsF4MOIT4z4fdfwNAyuntvIwt6iP7atPYvwA3arGD14=; b=BBpgm1NlnZhKSH87DRVYI3AiOhzjJ/q+7CpqM13H6AK9SrAM7t03D4sy3ofzfxOO85 xX1bvplar5BK2gUlCy4BuHy4C17duVGawvs1myHFzfpTp3CCMofjJDM1Vo+vYeXYyPj9 xB3lwuLqvozSSgMgkd4ETIQ5ehAr+QKLO+Cn0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=LsF4MOIT4z4fdfwNAyuntvIwt6iP7atPYvwA3arGD14=; b=CJHG2cJNErHP84qyC4ILeqqTZ7I5jQDTYxIht8Hs8yR3lCGr0OrWqw4668n715KN1/ Vw0WIQXMhhEc+CfPiMWrOCOFkWTa6+aObM/MnLjatLdKMVRgswaHD0T6pM53mysbnC6k Z/F+qLMcdiWLeNfesxK5bBiosipW4i0M3OpcDWGhZw9ON8gbp99GfYy50z05JCODIwc6 ocKvJuIkXHeTdSgrUXJplNvQP0XPMC0Suzw30A8cX0v7sohmHDR2rsr+78vssd5YGsxK PYKDOu1YjvBwbVlsUh+c00uC+r+WrVWesyxK2FYryp1iii0fwp/RJtBI6aWroDxZaTWu /NTg== X-Gm-Message-State: APjAAAUdiYmoUuqPGWVXFt1ng/pSr8y3UflUK74e8AnIDzJNmObnPyH1 WKzSvKldyAzd6Ip3nKh/XJg4UvJJSs4= X-Google-Smtp-Source: APXvYqyyiDNB/7Nz2PGpQaojBQJUROXMahgJR1nQmWE9UUZ8H0XmI2JbT58UtGX3OLjtB/wc6WTgYA== X-Received: by 2002:a63:28f:: with SMTP id 137mr8252384pgc.377.1553698427990; Wed, 27 Mar 2019 07:53:47 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id f125sm41335245pfc.91.2019.03.27.07.53.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 27 Mar 2019 07:53:47 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , keescook@chromium.org, kernel-team@android.com, kernel-hardening@lists.openwall.com, Andrew Morton , "Eric W. Biederman" , Matthew Wilcox , Michal Hocko , Oleg Nesterov Subject: [PATCH] Convert struct pid count to refcount_t Date: Wed, 27 Mar 2019 10:53:31 -0400 Message-Id: <20190327145331.215360-1-joel@joelfernandes.org> X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org struct pid's count is an atomic_t field used as a refcount. Use refcount_t for it which is basically atomic_t but does additional checking to prevent use-after-free bugs. No change in behavior if CONFIG_REFCOUNT_FULL=n. Cc: keescook@chromium.org Cc: kernel-team@android.com Cc: kernel-hardening@lists.openwall.com Signed-off-by: Joel Fernandes (Google) --- include/linux/pid.h | 5 +++-- kernel/pid.c | 8 ++++---- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/include/linux/pid.h b/include/linux/pid.h index 14a9a39da9c7..8cb86d377ff5 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -3,6 +3,7 @@ #define _LINUX_PID_H #include +#include enum pid_type { @@ -56,7 +57,7 @@ struct upid { struct pid { - atomic_t count; + refcount_t count; unsigned int level; /* lists of tasks that use this pid */ struct hlist_head tasks[PIDTYPE_MAX]; @@ -69,7 +70,7 @@ extern struct pid init_struct_pid; static inline struct pid *get_pid(struct pid *pid) { if (pid) - atomic_inc(&pid->count); + refcount_inc(&pid->count); return pid; } diff --git a/kernel/pid.c b/kernel/pid.c index 20881598bdfa..2095c7da644d 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -37,7 +37,7 @@ #include #include #include -#include +#include #include #include @@ -106,8 +106,8 @@ void put_pid(struct pid *pid) return; ns = pid->numbers[pid->level].ns; - if ((atomic_read(&pid->count) == 1) || - atomic_dec_and_test(&pid->count)) { + if ((refcount_read(&pid->count) == 1) || + refcount_dec_and_test(&pid->count)) { kmem_cache_free(ns->pid_cachep, pid); put_pid_ns(ns); } @@ -210,7 +210,7 @@ struct pid *alloc_pid(struct pid_namespace *ns) } get_pid_ns(ns); - atomic_set(&pid->count, 1); + refcount_set(&pid->count, 1); for (type = 0; type < PIDTYPE_MAX; ++type) INIT_HLIST_HEAD(&pid->tasks[type]); -- 2.21.0.392.gf8f6787159e-goog