From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 5A15E5616C9 for ; Fri, 11 Sep 2026 19:46:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156019; cv=none; b=uBN7GpQVlVGYhu6zRV7hs9kpHxJqOiZGX+UK3WaHyYpj0QmkYJpyeF8CUmn/8Gsw4iBersjtVjikYLBISM9Wb+IKvmrYLTog5gDZeUu+SMh7/Tu0FtILYA3R5BBgG3Y1BFpceefPbhHj1CvXdPFmdVVOkH4xjD2tAMsE4CbuSwM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156019; c=relaxed/simple; bh=gAG+bxd1mfbomkXr11hI+DrgM0HHGvqBzmrVj+uQy78=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=pQikd6CHAjQ++9CnWqYyji37graroh+gs+2oWvtNr7/HxfRoWFmuvJ7v6n5VWyGKIMQbAORFUiMhES4dU0t9jAbcEVAzbceOpJV0ib00HiNWVlsv6Fl2Vc3l302JllhpRZivCeFuHL6QjDoIy+J2IdpgSMWa7GiMensMB0CNQ6g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=d2b2tFAc; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="d2b2tFAc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A17B11F0089C; Fri, 11 Sep 2026 19:46:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156014; bh=i6pEmiMhvfGJ74RrZk0vpRVZ2yW6swhOmUzNgDlCN/c=; h=From:To:Cc:Subject:Date:Reply-To; b=d2b2tFAcdKhFYJ5dytkXyVH9m1hgks63TbBO5DFHO68V7eTj6wRGo4ze02+l6ADDY yyhAxE6xS+aKKI0QYB0vuSe80li2YURZhpL5t3kkJc4y86CP0BQ2hZPEsD6Xr8FhFc bRu1Sj1BghzvODQ2CgaEnAH490+KOHEhZQ0We5Z0= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-80934: wifi: mt76: mt7996: fix TX DMA mapping leak for AddBA req frames Date: Fri, 11 Sep 2026 21:40:40 +0200 Message-ID: <2026091136-CVE-2026-80934-4d3d@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3249; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=yedV9tmv4gBVq+MSatgWBJ0tsSI6F+mEf1lt22smwQs=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIk2emu6697Ns4+wHN73OqBaFthp59vSZLbdszrAzs F3qPWddRywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAExkfhfDPL2487VqK95eUYgz iF5TfTtx1R+XKQzzVBxLtXqNz6ZzbT7AF85ZmqCUJvUKAA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7996: fix TX DMA mapping leak for AddBA req frames mt7996/mt7992 hand the firmware a HW MAC-TXP for AddBA req action frames (MT_TXD7_MAC_TXD, set in mt7996_mac_write_txwi_80211()), but are otherwise FW-TXP devices. On tx free mt76_connac_txp_skb_unmap() therefore decodes the per-frame txp as a struct mt76_connac_fw_txp. For a MAC-TXP the fw_txp.nbuf byte aliases the AddBA TID word (MT_TXP1_TID_ADDBA), which is always zero, so the unmap loop runs zero times and the skb DMA mapping in buf[1] is never unmapped. buf[1].skip_unmap is set unconditionally, so the generic DMA-ring cleanup skips it as well. Each AddBA req therefore leaks one TX DMA mapping, roughly one per (re)association. With WED enabled these mappings are bounced through the WED swiotlb pool, so under continuous client reconnect churn the pool is exhausted after ~1-2 days, after which DMA mapping fails for WED, the WiFi MCU and other on-SoC consumers. Keep the deferred (token release) unmap that the design relies on, and add an mt7996-specific txp unmap that inspects MT_TXD7_MAC_TXD and unmaps buf[1] from the MAC-TXP layout for those frames, delegating to mt76_connac_txp_skb_unmap() otherwise. The Linux kernel CVE team has assigned CVE-2026-80934 to this issue. Affected and fixed versions =========================== Issue introduced in 6.18 with commit cb6ebbdffef2a888b95f121637cd1fad473919c6 and fixed in 6.18.50 with commit 01f2e0da8548f82d704b65b513026cfedc5f8962 Issue introduced in 6.18 with commit cb6ebbdffef2a888b95f121637cd1fad473919c6 and fixed in 7.2.4 with commit b754d3a6d44c53d9853eba374d8a7ef279a9d00a Issue introduced in 6.18 with commit cb6ebbdffef2a888b95f121637cd1fad473919c6 and fixed in 7.3-rc1 with commit deaa2e3656937fbbe312f0ee2616c756c6e2511f Issue introduced in 6.17.8 with commit 91a5a48702e948e45df01a4f2fd54a0b0d0d6efb Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-80934 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/net/wireless/mediatek/mt76/mt7996/mac.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/01f2e0da8548f82d704b65b513026cfedc5f8962 https://git.kernel.org/stable/c/b754d3a6d44c53d9853eba374d8a7ef279a9d00a https://git.kernel.org/stable/c/deaa2e3656937fbbe312f0ee2616c756c6e2511f