From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5E40315C82 for ; Mon, 5 Dec 2022 19:18:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6E72C433D6; Mon, 5 Dec 2022 19:18:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670267927; bh=jI84Pf+JECb3rH7o0BWyi5voV/0z+h+vV0EsZMh+aek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KOKaJea9DRyXpSHbKKE2HOCJwM7pJ1KBaAdKSxaXnCEMfKlSNGyCxzBim3WnCTtep gkeOED7hg95qEgrBd69WPKO0eX8SEt9bLacWMG9RTpMdqJho6Q+NpUWk7vLs+0wQB9 1oGVc23AZFkPBKOm3TC/Naa26TB4WlDOAvuCyRRY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xin Long , Jon Maloy , Jakub Kicinski , Sasha Levin Subject: [PATCH 4.19 024/105] tipc: add an extra conn_get in tipc_conn_alloc Date: Mon, 5 Dec 2022 20:08:56 +0100 Message-Id: <20221205190803.963395918@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221205190803.124472741@linuxfoundation.org> References: <20221205190803.124472741@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Xin Long [ Upstream commit a7b42969d63f47320853a802efd879fbdc4e010e ] One extra conn_get() is needed in tipc_conn_alloc(), as after tipc_conn_alloc() is called, tipc_conn_close() may free this con before deferencing it in tipc_topsrv_accept(): tipc_conn_alloc(); newsk = newsock->sk; <---- tipc_conn_close(); write_lock_bh(&sk->sk_callback_lock); newsk->sk_data_ready = tipc_conn_data_ready; Then an uaf issue can be triggered: BUG: KASAN: use-after-free in tipc_topsrv_accept+0x1e7/0x370 [tipc] Call Trace: dump_stack_lvl+0x33/0x46 print_report+0x178/0x4b0 kasan_report+0x8c/0x100 kasan_check_range+0x179/0x1e0 tipc_topsrv_accept+0x1e7/0x370 [tipc] process_one_work+0x6a3/0x1030 worker_thread+0x8a/0xdf0 This patch fixes it by holding it in tipc_conn_alloc(), then after all accessing in tipc_topsrv_accept() releasing it. Note when does this in tipc_topsrv_kern_subscr(), as tipc_conn_rcv_sub() returns 0 or -1 only, we don't need to check for "> 0". Fixes: c5fa7b3cf3cb ("tipc: introduce new TIPC server infrastructure") Signed-off-by: Xin Long Acked-by: Jon Maloy Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/tipc/topsrv.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/tipc/topsrv.c b/net/tipc/topsrv.c index 8ac27bd786f3..d3bb19cd0ec0 100644 --- a/net/tipc/topsrv.c +++ b/net/tipc/topsrv.c @@ -214,6 +214,7 @@ static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s, struct socket *s set_bit(CF_CONNECTED, &con->flags); con->server = s; con->sock = sock; + conn_get(con); spin_unlock_bh(&s->idr_lock); return con; @@ -491,6 +492,7 @@ static void tipc_topsrv_accept(struct work_struct *work) /* Wake up receive process in case of 'SYN+' message */ newsk->sk_data_ready(newsk); + conn_put(con); } } @@ -590,10 +592,11 @@ bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower, *conid = con->conid; rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub); - if (rc >= 0) - return true; + if (rc) + conn_put(con); + conn_put(con); - return false; + return !rc; } void tipc_topsrv_kern_unsubscr(struct net *net, int conid) -- 2.35.1