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 AC5604CC27E for ; Fri, 4 Sep 2026 15:58:50 +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=1788537532; cv=none; b=LJNeG2KyO40c4fW2sGDOdIAJ4F1NHwO+M/TYfki4CbFTbbjvBUBa9sypeVKVql54q5amgEmFPDGg8FeG9pOkHAh99+FMtZist5nCYtDVsOFhvzLwJ0/K+Kd0yzIGATEJCuV5ANX6UqT9EBSMXLL3y1TqZ9gUMKsfiV9NkLgsdVE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788537532; c=relaxed/simple; bh=YWOxwyY6//NMOgME3lOBq6oaf8r7E6tZGKTYh3UD0eU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Y1viN85ZAjKD8lB+Rx53xwsqp6IRj3xYjYwoioJlemo7P5IFmm1I6vjPDJfUomMRD+o/3cGpl8GyDEvkPpsfjhwkmKCJM1krdateMkAFQ+pp+c+czzLglDIew+gk0X4+7UmBx2kM5jWCHIZoAnwjj9+o2JlvIN+FsH4yJFGLB5I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DakkMWMr; 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="DakkMWMr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEECA1F00A3E; Fri, 4 Sep 2026 15:58:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788537530; bh=ggKMBM3DaR/yW43zm8kv19CBhZglB9wD/658Xn58+yk=; h=From:To:Cc:Subject:Date:Reply-To; b=DakkMWMrU2tHPNZkaNb/c33TGTRUeJqWzv6IiFJV16lDJeMGbz9Wq8kzqNHg82nwQ +Kt7zVVZL648pt2Trom0tV370JtQTY+afMgE58xQJMQf1B9zt5Y7aGXoKgeSYjsK9H d8d5mRsyOtK63WWqAxXtagOqZ14UNDVi0LFO0lso= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-80841: net/packet: defer vmalloc TX_RING free until skbs finish Date: Fri, 4 Sep 2026 17:53:08 +0200 Message-ID: <2026090458-CVE-2026-80841-56b6@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=3640; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=PqUB6Q/dm8AySHydPrJrlMNvgWtIfMuXyo3XK1ZWA5E=; b=owGbwMvMwCRo6H6F97bub03G02pJDFmzXkatvmF/fY5989wA8bWia3ZeCriSZuBhdD3cbtF53 3uOgiIxHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCRn3MYFlwSTe9ouOQV4M3z tjT3/ZkriX8DWhnmma7IudMS754Xzqd9MPd/yHmjzXsOAQA= 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: net/packet: defer vmalloc TX_RING free until skbs finish AF_PACKET TX_RING skbs keep a raw pointer to their ring frame. The skb page references preserve page-backed ring blocks after pg_vec is freed, but they do not preserve a vmalloc mapping. tpacket_destruct_skb() currently drops the pending reference before writing the timestamp and TP_STATUS_AVAILABLE to the frame. Move the decrement after those stores. The smp_wmb() in __packet_set_status() orders the frame stores before the decrement. Also recheck pending TX frames under pg_vec_lock before non-closing ring replacement, so a racing send cannot add a pending skb between the initial check and the ring swap. Ring allocation can produce a mixture of page-backed and vmalloc-backed blocks. Allocate deferred-work storage during TX ring setup when the first vmalloc-backed block is encountered, and keep its pointer in the pg_vec allocation header. If allocation fails, return -ENOMEM from ring setup. On socket close, a non-NULL pointer identifies a vmalloc-backed vector without a scan. If TX skbs remain, defer the whole vector to system_long_wq. After pg_vec is detached, a late destructor can skip the pending decrement. Use socket write-memory accounting as the deferred lifetime gate instead: an skb remains charged through its final sock_wfree(), after all ring-frame accesses. The delayed work retains a socket reference and reschedules itself until no TX skbs remain. Move pending_refcnt release to packet_sock_destruct() so late skb destructors and deferred cleanup can safely use it after packet_release(). Page-backed teardown remains synchronous, and no lock is added to the TX completion hot path. The Linux kernel CVE team has assigned CVE-2026-80841 to this issue. Affected and fixed versions =========================== Issue introduced in 3.14 with commit b013840810c221f2b0cf641d01531526052dc1fb and fixed in 7.1.13 with commit 0189dce07db2dc059ae0570e06758ec4233c6e11 Issue introduced in 3.14 with commit b013840810c221f2b0cf641d01531526052dc1fb and fixed in 7.2.3 with commit 550d00aa58193fb649a09a9c9e338c685adad784 Issue introduced in 3.14 with commit b013840810c221f2b0cf641d01531526052dc1fb and fixed in 7.3-rc1 with commit 992cc9f94ca924089a506ba9b327caa9af797529 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-2026-80841 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: net/packet/af_packet.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/0189dce07db2dc059ae0570e06758ec4233c6e11 https://git.kernel.org/stable/c/550d00aa58193fb649a09a9c9e338c685adad784 https://git.kernel.org/stable/c/992cc9f94ca924089a506ba9b327caa9af797529