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 4839E3921DB for ; Sun, 19 Jul 2026 12:04:20 +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=1784462662; cv=none; b=ZPvC0Mqh2n9zSQ11qC5eEZz8F1zj+4/tmn59p4nnvBQhgoaEX3yqbyVXn0mp/qhJ9LczkZGehEAlRAubfFtC3lQSOEJk9Ncx9e7TfRld8JErzJzsTLa+HkxzXZt9vvaVfhFB6UGBBqyuAzYFOXCOKNVVi/Y/fXO3nbuwhaSlFfY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784462662; c=relaxed/simple; bh=rFAk2w88x8RW/nVmm+hv+0Pq1BvpzbZ7UMQN3wPu1Xs=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=N5UW2EK3Mxh+DS4IahAyUd8qH0FfKyJAeF9tyCHWpUANdGGHznKhB3CM6tY6xxsCtSImr/H2YMk9gwPpF8foSaZ8a2otBakW7+wTEMoi8cXm3iZhtnqpCGFH46wOx8UTO+tpJiJJmDP3PAHbGTuDLTw/cjBXOzOUYY8hneHfN0c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yilO33e9; 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="yilO33e9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 656411F000E9; Sun, 19 Jul 2026 12:04:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784462660; bh=dledzfxHqZUtH4SxLWpGtG5DjmzefLX+LkoLUjDADQk=; h=From:To:Cc:Subject:Date:Reply-To; b=yilO33e9zEcvaEW3+CA/1WdXegDc6X26TUlDS2JZVNo5o6rrVRX2XtulZ1YE76uay h7ZGnJLFUDwwoXJ0u5QUi/OarXi0LRYpzObMFap+lffsud04zMwpIHmMiqYMYIr4C3 YHA5Il/RBFPkizXlSzsKHhHheZMWywmqDL/gkwEc= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-63830: net: skmsg: preserve sg.copy across SG transforms Date: Sun, 19 Jul 2026 14:02:47 +0200 Message-ID: <2026071908-CVE-2026-63830-1297@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=3774; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=ENn2G7ixUsyznWZ7b7k3FNZMCA7Sbc0o0szoXbJuG4M=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkxew6cXz1tekpX9dY7wa0cN7SXLzt+lUO6cFrQ39wbu +yzv5yK64hlYRBkYpAVU2T5so3n6P6KQ4pehranYeawMoEMYeDiFICJzHjAMIs54evLX19lm8JO TjqYdyy1f6+PiCzD/KwNitFKqvzhJ+vz585wPrbq1VOJeQA= 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: skmsg: preserve sg.copy across SG transforms The sk_msg sg.copy bitmap is part of the scatterlist entry ownership state. A set bit tells sk_msg_compute_data_pointers() not to expose the entry through writable BPF ctx->data. This protects entries backed by pages that are not private to the sk_msg, such as splice-backed file page-cache pages. Several sk_msg transform paths move, copy, split, or compact msg->sg.data[] entries without moving the matching sg.copy bit. This can make an externally backed entry arrive at a new slot with a clear copy bit. A later SK_MSG verdict can then expose sg_virt(sge) as writable ctx->data and BPF stores can modify the original page cache. Keep sg.copy synchronized with sg.data[] whenever entries are transferred, shifted, split, or copied into a new sk_msg. Clear the bit when an entry is replaced by a newly allocated private page or freed. This covers the BPF pull/push/pop helpers, sk_msg_shift_left/right(), sk_msg_xfer(), and tls_split_open_record(), including the partial tail entry created during TLS open-record splitting. The Linux kernel CVE team has assigned CVE-2026-63830 to this issue. Affected and fixed versions =========================== Issue introduced in 4.20 with commit d3b18ad31f93d0b6bae105c679018a1ba7daa9ca and fixed in 6.1.177 with commit 9bb86d8184b37503816150c4a6ad3c17dfdbe827 Issue introduced in 4.20 with commit d3b18ad31f93d0b6bae105c679018a1ba7daa9ca and fixed in 6.6.144 with commit 0eb4c16c4adb262763bda870a8ed38a1a9dec7ec Issue introduced in 4.20 with commit d3b18ad31f93d0b6bae105c679018a1ba7daa9ca and fixed in 6.12.95 with commit d22cc92bc41290e5783a72375e0843d9435f6001 Issue introduced in 4.20 with commit d3b18ad31f93d0b6bae105c679018a1ba7daa9ca and fixed in 6.18.38 with commit 1acdd14c0990dd1cd4b6534f00366d2e6dfce05f Issue introduced in 4.20 with commit d3b18ad31f93d0b6bae105c679018a1ba7daa9ca and fixed in 7.1.3 with commit 21ed9540a8e1906dfcbc1bb82ba9b4de4fa4bd6d Issue introduced in 4.20 with commit d3b18ad31f93d0b6bae105c679018a1ba7daa9ca and fixed in 7.2-rc1 with commit 406e8a651a7b854c41fecd5117bb282b3a6c2c6b 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-2026-63830 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: include/linux/skmsg.h net/core/filter.c net/core/skmsg.c net/tls/tls_sw.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/9bb86d8184b37503816150c4a6ad3c17dfdbe827 https://git.kernel.org/stable/c/0eb4c16c4adb262763bda870a8ed38a1a9dec7ec https://git.kernel.org/stable/c/d22cc92bc41290e5783a72375e0843d9435f6001 https://git.kernel.org/stable/c/1acdd14c0990dd1cd4b6534f00366d2e6dfce05f https://git.kernel.org/stable/c/21ed9540a8e1906dfcbc1bb82ba9b4de4fa4bd6d https://git.kernel.org/stable/c/406e8a651a7b854c41fecd5117bb282b3a6c2c6b