From patchwork Mon Jul 22 11:31:51 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nitin Gote X-Patchwork-Id: 11052201 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 5D753112C for ; Mon, 22 Jul 2019 11:35:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 49AEC205F6 for ; Mon, 22 Jul 2019 11:35:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3886226E69; Mon, 22 Jul 2019 11:35:54 +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=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 54FF9205F6 for ; Mon, 22 Jul 2019 11:35:52 +0000 (UTC) Received: (qmail 15742 invoked by uid 550); 22 Jul 2019 11:35:51 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 15717 invoked from network); 22 Jul 2019 11:35:50 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,294,1559545200"; d="scan'208";a="159853965" From: NitinGote To: keescook@chromium.org Cc: kernel-hardening@lists.openwall.com, paul@paul-moore.com, sds@tycho.nsa.gov, eparis@parisplace.org, omosnace@redhat.com, selinux@vger.kernel.org, linux-kernel@vger.kernel.org, NitinGote Subject: [PATCH] selinux: convert struct sidtab count to refcount_t Date: Mon, 22 Jul 2019 17:01:51 +0530 Message-Id: <20190722113151.1584-1-nitin.r.gote@intel.com> X-Mailer: git-send-email 2.17.1 X-Virus-Scanned: ClamAV using ClamSMTP refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: NitinGote --- security/selinux/ss/sidtab.c | 16 ++++++++-------- security/selinux/ss/sidtab.h | 2 +- 2 files changed, 9 insertions(+), 9 deletions(-) -- 2.17.1 diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c index e63a90ff2728..20fe235c6c71 100644 --- a/security/selinux/ss/sidtab.c +++ b/security/selinux/ss/sidtab.c @@ -29,7 +29,7 @@ int sidtab_init(struct sidtab *s) for (i = 0; i < SECINITSID_NUM; i++) s->isids[i].set = 0; - atomic_set(&s->count, 0); + refcount_set(&s->count, 0); s->convert = NULL; @@ -130,7 +130,7 @@ static struct context *sidtab_do_lookup(struct sidtab *s, u32 index, int alloc) static struct context *sidtab_lookup(struct sidtab *s, u32 index) { - u32 count = (u32)atomic_read(&s->count); + u32 count = refcount_read(&s->count); if (index >= count) return NULL; @@ -245,7 +245,7 @@ static int sidtab_reverse_lookup(struct sidtab *s, struct context *context, u32 *index) { unsigned long flags; - u32 count = (u32)atomic_read(&s->count); + u32 count = (u32)refcount_read(&s->count); u32 count_locked, level, pos; struct sidtab_convert_params *convert; struct context *dst, *dst_convert; @@ -272,7 +272,7 @@ static int sidtab_reverse_lookup(struct sidtab *s, struct context *context, spin_lock_irqsave(&s->lock, flags); convert = s->convert; - count_locked = (u32)atomic_read(&s->count); + count_locked = (u32)refcount_read(&s->count); level = sidtab_level_from_count(count_locked); /* if count has changed before we acquired the lock, then catch up */ @@ -315,7 +315,7 @@ static int sidtab_reverse_lookup(struct sidtab *s, struct context *context, } /* at this point we know the insert won't fail */ - atomic_set(&convert->target->count, count + 1); + refcount_set(&convert->target->count, count + 1); } if (context->len) @@ -328,7 +328,7 @@ static int sidtab_reverse_lookup(struct sidtab *s, struct context *context, /* write entries before writing new count */ smp_wmb(); - atomic_set(&s->count, count + 1); + refcount_set(&s->count, count + 1); rc = 0; out_unlock: @@ -418,7 +418,7 @@ int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params) return -EBUSY; } - count = (u32)atomic_read(&s->count); + count = (u32)refcount_read(&s->count); level = sidtab_level_from_count(count); /* allocate last leaf in the new sidtab (to avoid race with @@ -431,7 +431,7 @@ int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params) } /* set count in case no new entries are added during conversion */ - atomic_set(¶ms->target->count, count); + refcount_set(¶ms->target->count, count); /* enable live convert of new entries */ s->convert = params; diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h index bbd5c0d1f3bd..68dd96a5beba 100644 --- a/security/selinux/ss/sidtab.h +++ b/security/selinux/ss/sidtab.h @@ -70,7 +70,7 @@ struct sidtab_convert_params { struct sidtab { union sidtab_entry_inner roots[SIDTAB_MAX_LEVEL + 1]; - atomic_t count; + refcount_t count; struct sidtab_convert_params *convert; spinlock_t lock;