From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.222.52 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793315889; b=OLKjXlkzMj2p3xubiBFwx35RxP7uiHIA8aiJnkypC0YR7/u082oI0mBd/nBoOQd2hzLt H9QFiNB8yX9Bqyh0m4osqeyivnlrVcwq9TgdbJoJ3rdmA7vf3MXPSwMtWDYIi8bldfILy yn6zjgOCK8Qe+feR9uJBhfNx+9Cl+XJ2rS85w0TsRx2D9PGXFrNDRN4IuxfDmSV0NU4eE bizuygH7vpd6HkHex3BBTjmEoTddlCYeJxJfjJt6fQAQ3ebWfU7U5qLBBIgbXtcN4JScj RoQfDBaroMzboi+96do6nrAFzY4vC5n8Vn5qdv6gjyT+I9DbZTlOpZP4/PIpEFOIXvw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793315889; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:Content-Transfer-Encoding:MIME-Version; bh=Xpiy1fahTzksVX2ucGYHJCrX4DFe6BxdxTQ9XfdjhmY=; b=i1BI3j3UAQgfIfQ1WwBSGVwJfld+VNO8YL91zLFF3IH5GN2aEP7mXloN55ApQF8wLU3F pVL/4Go+3EGKxMCTxp7k8Sf0rcr9D0GN9gxQzq3AfOyWNHs2RX+q8ykLeGwx2nR7BeIKi DLIeJTbZrIP9/vu+wpd4vMfekOtx717MQgnWlr3YdMmo7MGnuISiW7asSjNaptRQCdmR7 dRP3fgqlE0oVC7UkElFQKu27QB4/T6AqqvXARoc6IftkmADCRgH4o0ghBxTRzcgjh11Xv wDzpIS74JWYv/HiIsKdgFdAq8CHDU0Tso4Sv0M2pKaiaHTzmszreleC6RL2sirZzpAw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=g6YoL8+b; arc=none smtp.remote-ip=209.85.222.52 Received: from mail-ua1-f52.google.com (mail-ua1-f52.google.com [209.85.222.52]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB2C7606A31E for ; Thu, 29 Oct 2026 23:18:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org BB2C7606A31E Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=g6YoL8+b Received: by mail-ua1-f52.google.com with SMTP id a1e0cc1a2514c-98c78660542so63831241.1 for ; Thu, 29 Oct 2026 16:18:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20260707; t=1793315888; x=1793920688; darn=vger.kernel.org; h=mime-version:content-transfer-encoding:content-type:references :in-reply-to:message-id:date:subject:cc:to:from:from:to:cc:subject :date:message-id:reply-to:content-type; bh=Xpiy1fahTzksVX2ucGYHJCrX4DFe6BxdxTQ9XfdjhmY=; b=g6YoL8+bqk59iYQ7kof6bxfFfXCqXet9J+PNuvC4HunJFJAUPPkl7as0TIN+2aC20G u3NZGt88u97DXe6wpqCYDfdW/5YmOCinYP31IupN+KFmNT3MO4nu4vEb+rMLGiTC+mCp dLyiR+1lerwbua+0mmRpst10/cVCrpERoLL3eLctyl2PvUTau69TM0T39HbrbkWZwggW /zc9ZHh0GXkWtz6QcMWFT0L9CF7oTq/7FzCcfip1Al8do5F0akyE3OIEJE2zGkQ5vsFs X/G3MYE9Eekplv8D6SDXKUZUlUVlikQhHy/fl5zqDfh7osdLInZr1u1DWnsefSgbl9Q5 N67A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793315888; x=1793920688; h=mime-version:content-transfer-encoding:content-type:references :in-reply-to:message-id:date:subject:cc:to:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Xpiy1fahTzksVX2ucGYHJCrX4DFe6BxdxTQ9XfdjhmY=; b=kCMKad0XvyWPmicz1QfrNSL6bOAkUx3IqzF3fHBjLHdU50QdJ9p3xDFZVr3cHn4KQI r8JZvqWOMCo+1czNNhILaHIbYX+8/XIafX98R0tJlbvjifKOI2xxjajLcHffIvTQYBp1 kX448K8Ui/rSoVZS7d1iFmdZGSjpxnrlAM+uMcUhexJnXlrUU2X7VHEOpU/Ly65KiDFw 601X9kkTxAG+aXM0cAyTaN4u6WRAJO59aVzZsaftBv642FopjDA4aIDfoDEe14s77oN+ pPRoDdAuGIJ8MkTz7lYIgtgh5N+XZmGeL62ee99vpGLAu/ZCkVBATL8/XIxIqfeN1KZ3 AwuA== X-Forwarded-Encrypted: i=1; AKwUvBxfnnEZIrrqgze8mhYFSZ/2VpK4MTK/k9jVQvj5Ffrh51cvBU6w0ml3AkYyjbrcNPF1TaD6Dnh0Tk94LZc=@vger.kernel.org X-Gm-Message-State: AFq9FYJS5msZl3zY4YVEXUS+41fvuf0heR+MxoMdP1vuuiYJQs3ciw1F sJyB9fUi+Vk4OkBrWfVAYZO/kCKqd2JcKa+kHixjCYiU+k0ZrnBekI3M X-Gm-Gg: AYBFou2XdD2aOQOJhkCdJkEiVL9Rg06kFedMZqdi3qp54OW5iFU6L8jLyUBHue812oN mrINZYZa/ZID89FsEPNMVGQntnjVdKz2NLG2KHyrBgHTX1qvpTxySvlPt+CgLIdUIel5trCrhq0 aED0aMiIjIKxOB3P6fRlNaTjhvIBKDu9s83qunvfAIQlgP9OAki5rtjAMqxWlifLmqLahqRqF6M FsywkEz+RziWQ9QHjoL1fj007X/5n2QaKXrpSINNtULd/zBhofW9Uu8m4CbDG+EQ9Wl+w8S4EZs x74vjNVaPrasKpZLrGZ0xw3NkfC4ry6ksYlFZZxbQCtZu6xD8fPe1hLfDqs+nLpzoG2AINm39Hq duCQL9CKlIfbCsvfdqLsxiPRpQhTMepy3JMpqKHV5fMKivF7QxJKA5GR/G+swJW4fwwo6rKkEOj /JXCsKqtsm7GslsxGIwQ20uwUCE7bhJnCVPgsBBb7wCmhEYooAkQa/XG55zwYH5UE8H5s1U4xuP JkpAUmPxYJBTQpRs6N6wfXuYvrx+nbJ6DbCzI8MLlZe1R2Dy+HexDLVdom/2ck9MCcz4o8MN52Q PySCi6SKEsL7z1KeI6u3VO55WsBQaVq8F83qFlmCUfecLFKOudPKFVHZiCxh5zyjn66icvFCuJV 8GUeEkikYM2n/+D+o3SdW1YZIk045+kw3yg== X-Received: by 2002:a67:e112:0:b0:79e:2b00:b4da with SMTP id ada2fe7eead31-7d07262b7c0mr332764137.6.1793315887662; Thu, 29 Oct 2026 16:18:07 -0700 (PDT) Received: from [192.168.15.16] ([2804:1b3:a2c1:77a1:5cd:8fee:f3c:4da7]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-992ee4e7453sm319509241.11.2026.10.29.16.18.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Oct 2026 16:18:07 -0700 (PDT) From: Joas Antonio dos Santos To: David Heidelberg Cc: David S. Miller , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Zhenghang Xiao , Sanghyun Park , oe-linux-nfc@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net 3/5] nfc: nci: consume the loopback response exactly once Date: Thu, 29 Oct 2026 20:17:35 -0300 Message-ID: <179331585573.30322.5511229003943288914@gmail.com> In-Reply-To: <179331585573.30322.4049957541187612575@gmail.com> References: <179331585573.30322.4049957541187612575@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 nci_nfcc_loopback_cb() stores the received data packet in conn_info->rx_skb and completes the request, and nci_nfcc_loopback() returns conn_info->rx_skb to the caller, which frees it. The pointer is never cleared. Any NCI response with a zero status also completes the request, as nci_req_complete() only checks NCI_REQ_PEND. If the NFCC sends one instead of the data packet, nci_nfcc_loopback() returns the skb of the previous loopback, which was already freed, or NULL. st_nci_loopback() then copies skb->data into its vendor command reply and frees the skb again. With an emulated NFCC on virtual_ncidev answering the second loopback with an unsolicited CORE_SET_CONFIG_RSP, nci_nfcc_loopback() returns 0 and the skb of the first loopback, and KASAN reports a slab-use-after-free as soon as the caller reads it. Detach the skb from conn_info when consuming it, free it when the caller does not want it, and return -EPROTO when the request was completed without a data packet. Fixes: 1c53855f6be2 ("nfc: nci: Add nci_nfcc_loopback to the nci core") Cc: stable@vger.kernel.org Signed-off-by: Joas Antonio dos Santos Assisted-by: Yaga Agent HackerSec Claude:claude-opus-5-5 --- net/nfc/nci/core.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index 73e3a9647..8e2a755ce 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -428,7 +428,7 @@ int nci_nfcc_loopback(struct nci_dev *ndev, const void *data, size_t data_len, int r; struct nci_loopback_data loopback_data; struct nci_conn_info *conn_info; - struct sk_buff *skb; + struct sk_buff *skb, *rx_skb; int conn_id = nci_get_conn_info_by_dest_type_params(ndev, NCI_DESTINATION_NFCC_LOOPBACK, NULL); @@ -464,8 +464,20 @@ int nci_nfcc_loopback(struct nci_dev *ndev, const void *data, size_t data_len, ndev->cur_conn_id = conn_id; r = nci_request(ndev, nci_send_data_req, &loopback_data, msecs_to_jiffies(NCI_DATA_TIMEOUT)); - if (r == NCI_STATUS_OK && resp) - *resp = conn_info->rx_skb; + if (r == NCI_STATUS_OK) { + /* Consume the stored data packet exactly once, see + * nci_nfcc_loopback_cb(). + */ + rx_skb = conn_info->rx_skb; + conn_info->rx_skb = NULL; + if (!rx_skb) + return -EPROTO; + + if (resp) + *resp = rx_skb; + else + kfree_skb(rx_skb); + } return r; } -- 2.43.0