From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) (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 2ACC83DFC9C; Fri, 17 Jul 2026 07:42:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=60.244.123.138 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784274150; cv=none; b=L5be+DPw+6KrGD8QYd4Sgui+z3h99lJjD71Pshft4P2ZXkJaKrhqtx3fgH11P5QARdYIE56OVlCsNdFKJ8VaNu/yxz2PlWPeILP3r+UupBoT9QT/IV+O6wQ5NW3/+Mti7Q4KUSrYNCAWZTOgI8yh4VXwnsZLj6et2rzztwJm98U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784274150; c=relaxed/simple; bh=shwkskL10faQToAwbbcrtKQlcWVRL3/zgz26jjdOR7w=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ETVS/TjUaGHkDMx8QAjreUxlTbPA9XUqJcRcDQH5a/GDdNo8mcl/ubkI3/ve8DMiXhXQrfHR5ZHP9w6CPQT3P0lBbmfn8MIrXPNn6b9nwUcyPXe+mMVLPEryD76vKa4jIaxJ5kk7UyPVLsoWB5/s/muc7pb3afJp+31Ti6xI3u4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com; spf=pass smtp.mailfrom=mediatek.com; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b=GipXf+hK; arc=none smtp.client-ip=60.244.123.138 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mediatek.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b="GipXf+hK" X-UUID: 04346b2081b311f1b1788b6acf885367-20260717 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:CC:To:From; bh=ZmTvoKDC7PrrRL2tdxxzKf0b2x6nEFuLyd0DX3GSMTw=; b=GipXf+hK97+nxb68GnqszSv52UrkXWbeJDwD4asH+Bug8gnx2GZxnHH9WDw/ZDEe2Lj3eGmViq9dUr99OkWVwW3epkNMpfS7tG2hPFhCF1AJndfjftdvOwtbeuYfr2B31xbqO17eXtIzAPnqMTa76CFyIV3kyyQX9AFY4QhqU8M=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.18,REQID:707a829b-4f20-498e-82d6-b8d1a2c9e939,IP:0,U RL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION: release,TS:0 X-CID-META: VersionHash:8a735a6,CLOUDID:7958f450-9df4-4a32-98eb-0af8dcdad6c0,B ulkID:nil,BulkQuantity:0,SF:81|82|102|836|865|888|898,TC:-5,Content:0|15|5 0|99|200|213,EDM:-3,IP:nil,URL:0,File:130,RT:0,Bulk:nil,QS:nil,BEC:-1,COL: 0,OSI:0,OSA:0,AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: 04346b2081b311f1b1788b6acf885367-20260717 Received: from mtkmbs14n2.mediatek.inc [(172.21.101.76)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 621985341; Fri, 17 Jul 2026 15:42:09 +0800 Received: from mtkmbs13n1.mediatek.inc (172.21.101.193) by MTKMBS14N1.mediatek.inc (172.21.101.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29; Fri, 17 Jul 2026 15:42:08 +0800 Received: from mtksitap99.mediatek.inc (10.233.130.16) by mtkmbs13n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.2562.29 via Frontend Transport; Fri, 17 Jul 2026 15:42:08 +0800 From: Chris Lu To: Marcel Holtmann , Johan Hedberg , Luiz Von Dentz CC: Sean Wang , Will Lee , SS Wu , Steve Lee , Paul Menzel , linux-bluetooth , linux-kernel , linux-mediatek , Chris Lu , Sashiko Subject: [PATCH v15 1/7] Bluetooth: btmtksdio: Fix SKB handling issues in TX path Date: Fri, 17 Jul 2026 15:42:00 +0800 Message-ID: <20260717074207.2869999-2-chris.lu@mediatek.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20260717074207.2869999-1-chris.lu@mediatek.com> References: <20260717074207.2869999-1-chris.lu@mediatek.com> Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Fix two SKB handling issues in btmtksdio_tx_packet(): 1. DMA out-of-bounds read: The driver aligns transfer size to 256 bytes using round_up(), but does not ensure the skb buffer has sufficient tailroom, causing DMA to read beyond the buffer. Fix by expanding skb tailroom if needed and zero-filling the padding. 2. Cloned SKB corruption: The driver modifies SKB header (via skb_push) and tail (via skb_put_zero) without checking if the SKB is cloned. If the Bluetooth core passes a cloned SKB (e.g., from L2CAP retransmission queues), the driver corrupts the shared data buffer for other subsystems. Fix by calling skb_unshare() at function entry to ensure we have a private copy before any modifications. Fixes: 9aebfd4a2200 ("Bluetooth: mediatek: add support for MediaTek MT7663S and MT7668S SDIO devices") Reported-by: Sashiko Signed-off-by: Chris Lu Assisted-by: Claude:Sonnet-4.5 --- drivers/bluetooth/btmtksdio.c | 46 +++++++++++++++++++++++++++++++---- 1 file changed, 41 insertions(+), 5 deletions(-) diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c index c6f80c419e90..42cb0bbb720f 100644 --- a/drivers/bluetooth/btmtksdio.c +++ b/drivers/bluetooth/btmtksdio.c @@ -272,9 +272,20 @@ static int btmtksdio_tx_packet(struct btmtksdio_dev *bdev, struct sk_buff *skb) { struct mtkbtsdio_hdr *sdio_hdr; + unsigned int padded_len, pad_len; int err; - /* Make sure that there are enough rooms for SDIO header */ + /* Ensure SKB is not cloned before any modification. + * If cloned (e.g., L2CAP retransmission queues), create a + * private copy to avoid corrupting shared data buffer. + */ + skb = skb_unshare(skb, GFP_ATOMIC); + if (!skb) + return -ENOMEM; + + /* Make sure that there are enough rooms for SDIO header. + * After skb_unshare(), we have exclusive ownership of the buffer. + */ if (unlikely(skb_headroom(skb) < sizeof(*sdio_hdr))) { err = pskb_expand_head(skb, sizeof(*sdio_hdr), 0, GFP_ATOMIC); @@ -290,20 +301,45 @@ static int btmtksdio_tx_packet(struct btmtksdio_dev *bdev, sdio_hdr->reserved = cpu_to_le16(0); sdio_hdr->bt_type = hci_skb_pkt_type(skb); + /* Calculate padded length for block-aligned DMA transfer. + * SDIO requires transfers to be block-aligned (MTK_SDIO_BLOCK_SIZE). + * Pad with zeros to prevent DMA from reading beyond skb buffer. + */ + padded_len = round_up(skb->len, MTK_SDIO_BLOCK_SIZE); + pad_len = padded_len - skb->len; + + if (pad_len > 0) { + /* Ensure sufficient tailroom for padding */ + if (unlikely(skb_tailroom(skb) < pad_len)) { + err = pskb_expand_head(skb, 0, pad_len, GFP_ATOMIC); + if (err < 0) + goto err_skb_pull; + /* Reassign sdio_hdr after buffer reallocation */ + sdio_hdr = (void *)skb->data; + } + + /* Zero-fill padding to prevent information disclosure */ + skb_put_zero(skb, pad_len); + } + clear_bit(BTMTKSDIO_HW_TX_READY, &bdev->tx_state); - err = sdio_writesb(bdev->func, MTK_REG_CTDR, skb->data, - round_up(skb->len, MTK_SDIO_BLOCK_SIZE)); + err = sdio_writesb(bdev->func, MTK_REG_CTDR, skb->data, padded_len); if (err < 0) - goto err_skb_pull; + goto err_skb_trim; - bdev->hdev->stat.byte_tx += skb->len; + /* Record actual transmitted data (excluding padding) */ + bdev->hdev->stat.byte_tx += le16_to_cpu(sdio_hdr->len); kfree_skb(skb); return 0; +err_skb_trim: + if (pad_len > 0) + skb_trim(skb, skb->len - pad_len); err_skb_pull: skb_pull(skb, sizeof(*sdio_hdr)); + kfree_skb(skb); return err; } -- 2.45.2