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 BE5BE1D142; Mon, 18 Dec 2023 14:07:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1JLl9Rmg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 411E4C433C8; Mon, 18 Dec 2023 14:07:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1702908470; bh=5nJSxEUNXIHwEH7WcFTtKjueoZeWOgaBPcPbxO7SzVw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1JLl9Rmg0EXDbeOs119vjb32tyrm52obi9V9t7iMKaw/YWKeIBvKYKz2wrBDPC0yv l2KsUnlLeEXpjuyxeJeJcFg7O92TrRK1CMjpBYKFm5mkbOHLGVD7rR+PATazngVJJI wmOHiVmyEbjz2kVna9rb/BU+w4uPjsZcl8H6ylIM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hyunwoo Kim , Paolo Abeni , Sasha Levin Subject: [PATCH 5.10 22/62] appletalk: Fix Use-After-Free in atalk_ioctl Date: Mon, 18 Dec 2023 14:51:46 +0100 Message-ID: <20231218135047.221519772@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231218135046.178317233@linuxfoundation.org> References: <20231218135046.178317233@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hyunwoo Kim [ Upstream commit 189ff16722ee36ced4d2a2469d4ab65a8fee4198 ] Because atalk_ioctl() accesses sk->sk_receive_queue without holding a sk->sk_receive_queue.lock, it can cause a race with atalk_recvmsg(). A use-after-free for skb occurs with the following flow. ``` atalk_ioctl() -> skb_peek() atalk_recvmsg() -> skb_recv_datagram() -> skb_free_datagram() ``` Add sk->sk_receive_queue.lock to atalk_ioctl() to fix this issue. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Hyunwoo Kim Link: https://lore.kernel.org/r/20231213041056.GA519680@v4bel-B760M-AORUS-ELITE-AX Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/appletalk/ddp.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c index c94b212d8e7ca..46adb8cefccf2 100644 --- a/net/appletalk/ddp.c +++ b/net/appletalk/ddp.c @@ -1811,15 +1811,14 @@ static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) break; } case TIOCINQ: { - /* - * These two are safe on a single CPU system as only - * user tasks fiddle here - */ - struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); + struct sk_buff *skb; long amount = 0; + spin_lock_irq(&sk->sk_receive_queue.lock); + skb = skb_peek(&sk->sk_receive_queue); if (skb) amount = skb->len - sizeof(struct ddpehdr); + spin_unlock_irq(&sk->sk_receive_queue.lock); rc = put_user(amount, (int __user *)argp); break; } -- 2.43.0