From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D57562F7EE2 for ; Sun, 28 Jun 2026 21:50:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782683428; cv=none; b=AZTuPvrFnBlZNN8ihfOUwmriCS5LA803ZJtNZ5r/+DzvXjyXSsfNHt5kQkAFSCjvC+ahrsuTdyODdU+WpCOLsZN4XUbPiBaV0rM/pB7mDQ35WqJBQf3B7DZxrNCdRnR0uNP7kxqAbflUPDIGr0wosGhkDHLMcsOmWhzXgBLpZPM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782683428; c=relaxed/simple; bh=4qFHrJ8TjRhzwg9eX6E4uCk78ScEs4rJofH5o2OZmu8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=lvgYMxP58XAAVwio4qL5zQjQFQyqevDw08QkMBFr4CcnwjKT9kOy+/CqehpDkuMdB7kDGMBYB7uNdG+Eycqw6iw2FGfsRtg+tCxbxND9268cjbvXx5dgLMp1i+Du2Nrq3RPP367pL5RNgCuhFYDwaSW/aTpXwJhy+Rt7E1BbXP0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=BlmrVxOL; arc=none smtp.client-ip=209.85.214.169 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) header.d=gmail.com header.i=@gmail.com header.b="BlmrVxOL" Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-2c9b42be8feso10374735ad.2 for ; Sun, 28 Jun 2026 14:50:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1782683426; x=1783288226; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=4xJeWro39OB82LbHgE7JTjiXJkNJO0xjWGuLEsvgMVw=; b=BlmrVxOLuMWywpvxEAR7aOzqiogLp74+5JIaPgaEwcmYgoLPqdOnaDCRJOhbynQ0p0 T8XUfsRe1WseWBB5V0zm8MpcVoU70WqAuzJ0Dcsrlod/aUXr/3ySL8OY2ECd00R3U+ZK CN8F94HYkVYkaFfravcdCP9hiQQU7FQQgnXrsrBeETJI86uZl9Tcrbd+ltj7S3oO+BWx +OGLOHMyCukZ3YtoARPQnT7lfc7PqctmxbjMbjueC2IzyWsqm5mi1y0GzX3d1nT52HUp ntWCjXIL86LT5obNzfQd2romE50TPWQUM13i8kRDPJfCMy4FEDsePt6stIRwSbUGQcga UjNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782683426; x=1783288226; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=4xJeWro39OB82LbHgE7JTjiXJkNJO0xjWGuLEsvgMVw=; b=H8htR7H/m7V5alUqPTVNjJhlXJ+5WNdNstpjX/imk4XmRqW8PAhYPn/HqZqjRcRxdh an1/o+jGPfcRJT8VimiSHSINwEgqc1PpyFb3LSks6e0wSVfC0UYbRGjuQFEQ3G/w0gWM Zc6zKWdO7zSAwX7lPfJHJVxLbzLPVZXprZlrA74hBBc7pcQweixlii3mvIGcYk0LAORD VyJH1xjYSV839k4KTu109a3iOG4Aatjmqi36UR4K0GCLAdd+Wde0Th3gMhkDXN2OoZUr PfU58EKL7gx5ZrqU3tNnEXJf4JmrGfuBFwEVcjtgI0rIPK8NQht4MmwOj5Utp+GvfoJ5 z29A== X-Forwarded-Encrypted: i=1; AHgh+Rpwi9bNGBuFkrmUiYo96FigYI7PQT4DUNHdPq/jcnMjwWGM+9RP87XqmGA4kbIRDh0xHmHVoaMUdu4avyE=@vger.kernel.org X-Gm-Message-State: AOJu0Yz3qoMrmTt3Je1PzGTc+pxskH367YaGUs2r1nSkDjc6nj/rVlF5 mHkNIYg6JI7iHxxywlDBlqQQ5zsz6KntTY1sAL2zpQJoSNqLRaeuXCez X-Gm-Gg: AfdE7clLn5o+wqpBFOirOZ7URxas4p9ES4NZLd841dL9xWuzMqAwdJUHx1hwBvmc82H fz8HIxk3c1JmUwyckn73YX8CINoFPt/NRXS/8yQI0H4wbSH42D4OnKFm1xAxqlwBdmJQvx0OL95 38OS9nDV8cc2h2gQcPAgCINAKULJ2y2TzBMli34kKqyi8tU/ICFe9l6ZD9rOYI0J9SRIK8YFQC3 eghfl8YloObUIF7L3IRpqWUI0ciPfTQHH3k/hqQxWOPrVJ6IAcUB1d3G7OJrAdEjbWLfHvUVjuO erKbbLGleY7fkSfoqA4dcclLI4+va/kAZYPmxps/wX/RIwarC3bNNESC2VlqU1J9VxpJwWuMNk5 wnEleiAGMg+qUdu9nq95cM2tTSDV9zhclhH8BP+/b0ILFn8bm6SQ/Bh7wGP49c0m80xDaIesSRf iKMXoYJRdOGS/UZz24S0h7ZVFz3v8snCUViL2mIIiU8fbNZlDwt4A9YxymYWl4nw== X-Received: by 2002:a17:903:1cc:b0:2ca:281:27fa with SMTP id d9443c01a7336-2ca02812986mr8901775ad.37.1782683426051; Sun, 28 Jun 2026 14:50:26 -0700 (PDT) Received: from node ([149.40.62.34]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2c9e95e49efsm14044425ad.52.2026.06.28.14.50.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 28 Jun 2026 14:50:25 -0700 (PDT) From: Muhammad Bilal To: david@ixit.cz Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, oe-linux-nfc@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Muhammad Bilal Subject: [PATCH net v2] nfc: nci: fix use of uninitialized memory in NFC-DEP general bytes Date: Mon, 29 Jun 2026 02:49:29 +0500 Message-ID: <20260628214929.135152-1-meatuni001@gmail.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit nci_store_general_bytes_nfc_dep() derives the length of the NFC-DEP general bytes by subtracting the fixed general-bytes offset from the ATR length: atr_res_len - NFC_ATR_RES_GT_OFFSET (poll, offset 15) atr_req_len - NFC_ATR_REQ_GT_OFFSET (listen, offset 14) It never checks that the ATR is at least that long. When a RF_INTF_ACTIVATED_NTF reports an ATR shorter than the offset the subtraction is negative; because min_t() casts its arguments to __u8 the negative value becomes large and is then capped at NFC_ATR_RES_GB_MAXSIZE / NFC_ATR_REQ_GB_MAXSIZE. remote_gb_len is thus set to up to 47/48 even though only atr_res_len/atr_req_len bytes of the on-stack atr_res/atr_req buffer were copied from the packet, and the following memcpy() reads the uninitialized remainder into ndev->remote_gb. Zero remote_gb_len and skip storing the general bytes when the ATR is shorter than the general-bytes offset, so that a stale remote_gb_len from a previous activation does not survive into the new session. Fixes: a99903ec4566 ("NFC: NCI: Handle Target mode activation") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal --- net/nfc/nci/ntf.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/nfc/nci/ntf.c b/net/nfc/nci/ntf.c index 802928ca4d51e..b72545daa2051 100644 --- a/net/nfc/nci/ntf.c +++ b/net/nfc/nci/ntf.c @@ -654,8 +654,10 @@ static int nci_store_general_bytes_nfc_dep(struct nci_dev *ndev, case NCI_NFC_A_PASSIVE_POLL_MODE: case NCI_NFC_F_PASSIVE_POLL_MODE: if (ntf->activation_params.poll_nfc_dep.atr_res_len < - NFC_ATR_RES_GT_OFFSET) + NFC_ATR_RES_GT_OFFSET) { + ndev->remote_gb_len = 0; break; + } ndev->remote_gb_len = min_t(__u8, (ntf->activation_params.poll_nfc_dep.atr_res_len - NFC_ATR_RES_GT_OFFSET), @@ -669,8 +671,10 @@ static int nci_store_general_bytes_nfc_dep(struct nci_dev *ndev, case NCI_NFC_A_PASSIVE_LISTEN_MODE: case NCI_NFC_F_PASSIVE_LISTEN_MODE: if (ntf->activation_params.listen_nfc_dep.atr_req_len < - NFC_ATR_REQ_GT_OFFSET) + NFC_ATR_REQ_GT_OFFSET) { + ndev->remote_gb_len = 0; break; + } ndev->remote_gb_len = min_t(__u8, (ntf->activation_params.listen_nfc_dep.atr_req_len - NFC_ATR_REQ_GT_OFFSET), -- 2.54.0