From patchwork Mon Dec 4 13:08:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Siddh Raman Pant X-Patchwork-Id: 13478353 X-Patchwork-Delegate: kuba@kernel.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=siddh.me header.i=code@siddh.me header.b="CXRmlxmN" Received: from sender-of-o51.zoho.in (sender-of-o51.zoho.in [103.117.158.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5739ED5B; Mon, 4 Dec 2023 05:09:05 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1701695309; cv=none; d=zohomail.in; s=zohoarc; b=FuJc7I9gI1RkTq8sK+QC5tIAlRPr+gnyONRuBkcwoeFW0R7cEa877xmmErxmSNNcnlm9KZv6ZK/jgdWNvh9HWlLkZAhxlsg8uQ61KhzgH6cwiEQ/vortwlpHmCNwDzaaTUy7IVXqY2lUBjILkUW+JHJz38leeK83bl7zcW41mrU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.in; s=zohoarc; t=1701695309; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=R3iDLTqqyWsCW/yZ9x9fWDYA3oYZ6WCh4COkmNHdQK4=; b=a48H7NBxEMBntfGwtB5CvG3I8k9j5o6RLZ2GJ63nHW0Sl5zTHsWluBLBvNFvai5zsq4ch3DyBgjmlI96msXUujX731N7Eq+M7vKXFPDd4P4YwQnN5D14Cnj+WHDVc8VQRSxDgdD1aw4gx9qjsLs8ugNPQn4mDYscrdlfuPpYmls= ARC-Authentication-Results: i=1; mx.zohomail.in; dkim=pass header.i=siddh.me; spf=pass smtp.mailfrom=code@siddh.me; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1701695309; s=zmail; d=siddh.me; i=code@siddh.me; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=R3iDLTqqyWsCW/yZ9x9fWDYA3oYZ6WCh4COkmNHdQK4=; b=CXRmlxmNsWzehyzUEEgqV5rDvEO2SimcT6ofZlkfeHZ4ohHwYY30iC7Z4x0Ggor3 biFmmQqk04h7kN+fDNs+8x6U3xt2q7E9hx1xQflOmRFsi3BbGpPztZoAPhUx2zzPwEQ RFWLQUnYWBp2vWRYwo8gIBieetIzZ8aEwJ1XMlNw= Received: from kampyooter.. (223.229.148.242 [223.229.148.242]) by mx.zoho.in with SMTPS id 1701695308534654.1773373137597; Mon, 4 Dec 2023 18:38:28 +0530 (IST) From: Siddh Raman Pant To: Krzysztof Kozlowski , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Suman Ghosh Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+bbe84a4010eeea00982d@syzkaller.appspotmail.com Subject: [PATCH net-next v3 1/2] nfc: llcp_core: Hold a ref to llcp_local->dev when holding a ref to llcp_local Date: Mon, 4 Dec 2023 18:38:21 +0530 Message-ID: <4143dc4398aa4940a76d3f375ec7984e98891a11.1701627492.git.code@siddh.me> X-Mailer: git-send-email 2.42.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ZohoMailClient: External X-Patchwork-Delegate: kuba@kernel.org llcp_sock_sendmsg() calls nfc_llcp_send_ui_frame() which in turn calls nfc_alloc_send_skb(), which accesses the nfc_dev from the llcp_sock for getting the headroom and tailroom needed for skb allocation. Parallelly the nfc_dev can be freed, as the refcount is decreased via nfc_free_device(), leading to a UAF reported by Syzkaller, which can be summarized as follows: (1) llcp_sock_sendmsg() -> nfc_llcp_send_ui_frame() -> nfc_alloc_send_skb() -> Dereference *nfc_dev (2) virtual_ncidev_close() -> nci_free_device() -> nfc_free_device() -> put_device() -> nfc_release() -> Free *nfc_dev When a reference to llcp_local is acquired, we do not acquire the same for the nfc_dev. This leads to freeing even when the llcp_local is in use, and this is the case with the UAF described above too. Thus, when we acquire a reference to llcp_local, we should acquire a reference to nfc_dev, and release the references appropriately later. References for llcp_local is initialized in nfc_llcp_register_device() (which is called by nfc_register_device()). Thus, we should acquire a reference to nfc_dev there. nfc_unregister_device() calls nfc_llcp_unregister_device() which in turn calls nfc_llcp_local_put(). Thus, the reference to nfc_dev is appropriately released later. Reported-and-tested-by: syzbot+bbe84a4010eeea00982d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=bbe84a4010eeea00982d Fixes: c7aa12252f51 ("NFC: Take a reference on the LLCP local pointer when creating a socket") Signed-off-by: Siddh Raman Pant Reviewed-by: Suman Ghosh --- net/nfc/llcp_core.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c index 1dac28136e6a..9d45ce6dcdca 100644 --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -145,6 +145,9 @@ static void nfc_llcp_socket_release(struct nfc_llcp_local *local, bool device, static struct nfc_llcp_local *nfc_llcp_local_get(struct nfc_llcp_local *local) { + if (!nfc_get_device(local->dev->idx)) + return NULL; + kref_get(&local->ref); return local; @@ -180,6 +183,7 @@ int nfc_llcp_local_put(struct nfc_llcp_local *local) if (local == NULL) return 0; + nfc_put_device(local->dev); return kref_put(&local->ref, local_release); } @@ -959,8 +963,18 @@ static void nfc_llcp_recv_connect(struct nfc_llcp_local *local, } new_sock = nfc_llcp_sock(new_sk); - new_sock->dev = local->dev; + new_sock->local = nfc_llcp_local_get(local); + if (!new_sock->local) { + reason = LLCP_DM_REJ; + release_sock(&sock->sk); + sock_put(&sock->sk); + sock_put(&new_sock->sk); + nfc_llcp_sock_free(new_sock); + goto fail; + } + + new_sock->dev = local->dev; new_sock->rw = sock->rw; new_sock->miux = sock->miux; new_sock->nfc_protocol = sock->nfc_protocol; @@ -1597,7 +1611,13 @@ int nfc_llcp_register_device(struct nfc_dev *ndev) if (local == NULL) return -ENOMEM; - local->dev = ndev; + /* Hold a reference to the device. */ + local->dev = nfc_get_device(ndev->idx); + if (!local->dev) { + kfree(local); + return -ENODEV; + } + INIT_LIST_HEAD(&local->list); kref_init(&local->ref); mutex_init(&local->sdp_lock); From patchwork Mon Dec 4 13:08:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Siddh Raman Pant X-Patchwork-Id: 13478352 X-Patchwork-Delegate: kuba@kernel.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=siddh.me header.i=code@siddh.me header.b="fZFzcVqI" Received: from sender-of-o51.zoho.in (sender-of-o51.zoho.in [103.117.158.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63B8FD6C; Mon, 4 Dec 2023 05:09:06 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1701695310; cv=none; d=zohomail.in; s=zohoarc; b=KYKagfJwLJR/l2o8XdfQVvnTVoHBVbs/XFi1NE+ZFOzvPe9C3MeySQ6dsR7fuVze0enMACOpYdyse/VXY4TQOpztCd15R/HQt1dFpQo+0PIaRIxYhokDzi8H+w1lZpMeLsUZuZa3OirrMlDF+P5attVlRK71URPWgknHGqceuo4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.in; s=zohoarc; t=1701695310; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=hsnJ/KNlUs6XiyX2XlbfSpC3bHgmAF/BmM03d8xcwm0=; b=JD6UklVpZawlW1B9bazsFAdMttK/iEEh6W47YGXECq1gfQzXSDbz1EBzeCpM4FEi1z8o5Fa4P3EEhV/F+7RmIzy+b8eVYQphWBZZfcHGX8CvAb3kuIsvfL2LT/a2Mps3WTcwiz8MsVO/k/K52uxBmGW9nBnB7aUjljZLjLgLoaA= ARC-Authentication-Results: i=1; mx.zohomail.in; dkim=pass header.i=siddh.me; spf=pass smtp.mailfrom=code@siddh.me; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1701695310; s=zmail; d=siddh.me; i=code@siddh.me; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=hsnJ/KNlUs6XiyX2XlbfSpC3bHgmAF/BmM03d8xcwm0=; b=fZFzcVqId17iVSznukaO7vQYfftfVedXOqu0E3Xx9IHvtMr1JZUQVWuFZBWeRZwc JDm8i+f3I+w0UvjU6WCKAjd/Kv5aHQMZ1sSRBM3uAqdnv+VSNFM2Ba+MpSsrPPRgSEM PlFcAHRQGxUy4LMsKZ+VcWT4Z4zOv06xCvGfCt/M= Received: from kampyooter.. (223.229.148.242 [223.229.148.242]) by mx.zoho.in with SMTPS id 1701695308912849.1027651405482; Mon, 4 Dec 2023 18:38:28 +0530 (IST) From: Siddh Raman Pant To: Krzysztof Kozlowski , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Suman Ghosh Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v3 2/2] nfc: Do not send datagram if socket state isn't LLCP_BOUND Date: Mon, 4 Dec 2023 18:38:22 +0530 Message-ID: <727e1ff5df5e8d36e19b25155b1555ed3fd0cdfe.1701627492.git.code@siddh.me> X-Mailer: git-send-email 2.42.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ZohoMailClient: External X-Patchwork-Delegate: kuba@kernel.org As we know we cannot send the datagram (state can be set to LLCP_CLOSED by nfc_llcp_socket_release()), there is no need to proceed further. Thus, bail out early from llcp_sock_sendmsg(). Signed-off-by: Siddh Raman Pant Reviewed-by: Krzysztof Kozlowski Reviewed-by: Suman Ghosh --- net/nfc/llcp_sock.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c index 645677f84dba..819157bbb5a2 100644 --- a/net/nfc/llcp_sock.c +++ b/net/nfc/llcp_sock.c @@ -796,6 +796,11 @@ static int llcp_sock_sendmsg(struct socket *sock, struct msghdr *msg, } if (sk->sk_type == SOCK_DGRAM) { + if (sk->sk_state != LLCP_BOUND) { + release_sock(sk); + return -ENOTCONN; + } + DECLARE_SOCKADDR(struct sockaddr_nfc_llcp *, addr, msg->msg_name);