From patchwork Wed May 22 22:28:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 10956721 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9E3D776 for ; Wed, 22 May 2019 22:28:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B1F5F204BA for ; Wed, 22 May 2019 22:28:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A07CE205FC; Wed, 22 May 2019 22:28:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 338E9205C0 for ; Wed, 22 May 2019 22:28:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728050AbfEVW2M (ORCPT ); Wed, 22 May 2019 18:28:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50846 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725823AbfEVW2M (ORCPT ); Wed, 22 May 2019 18:28:12 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BC26E30821AE; Wed, 22 May 2019 22:28:11 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-121-142.rdu2.redhat.com [10.10.121.142]) by smtp.corp.redhat.com (Postfix) with ESMTP id C8E1B60BF1; Wed, 22 May 2019 22:28:10 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 1/7] keys: sparse: Fix key_fs[ug]id_changed() From: David Howells To: keyrings@vger.kernel.org Cc: dhowells@redhat.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 22 May 2019 23:28:10 +0100 Message-ID: <155856409010.10428.11692778420533145488.stgit@warthog.procyon.org.uk> In-Reply-To: <155856408314.10428.17035328117829912815.stgit@warthog.procyon.org.uk> References: <155856408314.10428.17035328117829912815.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Wed, 22 May 2019 22:28:11 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Sparse warnings are incurred by key_fs[ug]id_changed() due to unprotected accesses of tsk->cred, which is marked __rcu. Fix this by passing the new cred struct to these functions from commit_creds() rather than the task pointer. Signed-off-by: David Howells Reviewed-by: James Morris --- include/linux/key.h | 8 ++++---- kernel/cred.c | 4 ++-- security/keys/process_keys.c | 22 ++++++++++------------ 3 files changed, 16 insertions(+), 18 deletions(-) diff --git a/include/linux/key.h b/include/linux/key.h index 7099985e35a9..1f09aad1c98c 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -402,8 +402,8 @@ extern struct ctl_table key_sysctls[]; * the userspace interface */ extern int install_thread_keyring_to_cred(struct cred *cred); -extern void key_fsuid_changed(struct task_struct *tsk); -extern void key_fsgid_changed(struct task_struct *tsk); +extern void key_fsuid_changed(struct cred *new_cred); +extern void key_fsgid_changed(struct cred *new_cred); extern void key_init(void); #else /* CONFIG_KEYS */ @@ -418,8 +418,8 @@ extern void key_init(void); #define make_key_ref(k, p) NULL #define key_ref_to_ptr(k) NULL #define is_key_possessed(k) 0 -#define key_fsuid_changed(t) do { } while(0) -#define key_fsgid_changed(t) do { } while(0) +#define key_fsuid_changed(c) do { } while(0) +#define key_fsgid_changed(c) do { } while(0) #define key_init() do { } while(0) #endif /* CONFIG_KEYS */ diff --git a/kernel/cred.c b/kernel/cred.c index 45d77284aed0..3bd40de9e192 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -455,9 +455,9 @@ int commit_creds(struct cred *new) /* alter the thread keyring */ if (!uid_eq(new->fsuid, old->fsuid)) - key_fsuid_changed(task); + key_fsuid_changed(new); if (!gid_eq(new->fsgid, old->fsgid)) - key_fsgid_changed(task); + key_fsgid_changed(new); /* do it * RLIMIT_NPROC limits on user->processes have already been checked diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index f05f7125a7d5..ba5d3172cafe 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -293,28 +293,26 @@ static int install_session_keyring(struct key *keyring) /* * Handle the fsuid changing. */ -void key_fsuid_changed(struct task_struct *tsk) +void key_fsuid_changed(struct cred *new_cred) { /* update the ownership of the thread keyring */ - BUG_ON(!tsk->cred); - if (tsk->cred->thread_keyring) { - down_write(&tsk->cred->thread_keyring->sem); - tsk->cred->thread_keyring->uid = tsk->cred->fsuid; - up_write(&tsk->cred->thread_keyring->sem); + if (new_cred->thread_keyring) { + down_write(&new_cred->thread_keyring->sem); + new_cred->thread_keyring->uid = new_cred->fsuid; + up_write(&new_cred->thread_keyring->sem); } } /* * Handle the fsgid changing. */ -void key_fsgid_changed(struct task_struct *tsk) +void key_fsgid_changed(struct cred *new_cred) { /* update the ownership of the thread keyring */ - BUG_ON(!tsk->cred); - if (tsk->cred->thread_keyring) { - down_write(&tsk->cred->thread_keyring->sem); - tsk->cred->thread_keyring->gid = tsk->cred->fsgid; - up_write(&tsk->cred->thread_keyring->sem); + if (new_cred->thread_keyring) { + down_write(&new_cred->thread_keyring->sem); + new_cred->thread_keyring->gid = new_cred->fsgid; + up_write(&new_cred->thread_keyring->sem); } }