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 8D08D372696 for ; Sat, 15 Aug 2026 06:23:27 +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=1786775008; cv=none; b=UhZLrJiCRJGHgN5g4vWQkNP0fUshNUH9Z1DpEDeUPGBHla6Kv59bhIIOi1rqf/9DtDholYWPaDPHer+sldB+hsFMwBcjeKSJwFxI5MX+9Bz4xTlL1PMwy+5/JyEznh3vsMYf/Up5L5W3Nf9A/AlONRN0i/QZBTpAoK+SIW7BQaQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775008; c=relaxed/simple; bh=tMzRBlGo4Nl3EVK6FxEhLdxUB5k/Mzt2biKFEylKcNU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=IfV6Ay2Wpq3/r5edE0SRyYySoj2cG+U22odQRXrd/LyXlPcbLpU+R4BEE2qzuJyGNthMcCmsX3xe6Hryzu/eVF9l0jl/oKQhlJb+Lp0t+JeoDy8JKnhMMIQwp3vf/K6xA+Ya7duNmHqNKVHKGD6uIPeoCi1DSrYVVOL4Ldi//ac= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CvnZwDje; 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="CvnZwDje" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3FF41F000E9; Sat, 15 Aug 2026 06:23:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786775007; bh=ekoKLjiS11GcPW89VVoIEOjs3WgFDNLzi4Xp30YAwxQ=; h=From:To:Cc:Subject:Date:Reply-To; b=CvnZwDjerVbTG+r/kpumhw+ZlgOYMcM+SQxxETPOa5AVTcSbNnKEpGbI9IuGO5Qi9 vymZwgJgBh74nI2aj0+rU8spuiXdkWHCuXlrFGPenQIEmWBorpIzn4OdUtmmKSfNbA Gvo9aTxcm0MjkyEiT0KPZDqUlTMAfukt33L8tgsI= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-72343: net/mlx5e: Fix HV VHCA stats zero-sized buffer allocation Date: Sat, 15 Aug 2026 15:07:02 +0900 Message-ID: <2026081510-CVE-2026-72343-b443@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=5118; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=bZYiN9EtaQu9zaO4/a+JnHwvuk0Ru9lC9GmJZYnSbyA=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNDI+etyvo2DI/65r7eNKikpO1V0uLJcW5dodebE284 NB70V+0I4aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACbybz/DguuMobnpTvHnPtx4 xNkosXlapU10EsNUuecKu5RlXjvtWm161UngIGOaHTMA 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/mlx5e: Fix HV VHCA stats zero-sized buffer allocation mlx5e_hv_vhca_stats_create() is called from mlx5e_nic_enable(), before mlx5e_open(). At that point priv->stats_nch is still zero, because it is only ever incremented in mlx5e_channel_stats_alloc(), which is reached only from mlx5e_open_channel(). mlx5e_hv_vhca_stats_buf_size() therefore returns 0, and kvzalloc(0, GFP_KERNEL) returns ZERO_SIZE_PTR ((void *)16) rather than NULL. The "if (!buf)" guard does not catch this, and mlx5e_hv_vhca_stats_create() completes "successfully" with priv->stats_agent.buf set to ZERO_SIZE_PTR. Once channels are opened (priv->stats_nch > 0) and the hypervisor enables stats reporting, mlx5e_hv_vhca_stats_work() recomputes buf_len using the new non-zero stats_nch and calls memset(buf, 0, buf_len) on ZERO_SIZE_PTR, faulting at address 0x10. Allocate the buffer based on priv->max_nch, which is set in mlx5e_priv_init() and is the upper bound on stats_nch: - Add a separate helper mlx5e_hv_vhca_stats_buf_max_size() that returns sizeof(per_ring_stats) * max(max_nch, stats_nch), and use it for the kvzalloc() in mlx5e_hv_vhca_stats_create(). - Keep mlx5e_hv_vhca_stats_buf_size() (which returns based on stats_nch) for the worker's active payload size, so the wire format (block->rings = stats_nch) and the amount of data filled by mlx5e_hv_vhca_fill_stats() are unchanged. The max(max_nch, stats_nch) guard handles the rare case where mlx5e_attach_netdev() recomputes max_nch downward across a detach/resume cycle while priv->stats_nch persists (mlx5e_detach_netdev does not call mlx5e_priv_cleanup, so stats_nch is only reset when the netdev is destroyed). Without the guard, the worker could compute buf_len from stats_nch and overrun the smaller buffer allocated based on the reduced max_nch. Allocating a non-zero buffer also makes the kvzalloc() failure path in mlx5e_hv_vhca_stats_create() reachable for the first time: it returns early without (re)creating the agent. Clear priv->stats_agent.{agent,buf} in mlx5e_hv_vhca_stats_destroy() after freeing them, so that if a later create() bails out on this path, a subsequent teardown does not double-free the stale agent/buffer left from a previous enable/disable cycle. This mirrors the existing mlx5e pattern of preallocating arrays of size max_nch (e.g. priv->channel_stats) and lazily populating entries up to stats_nch on demand. The Linux kernel CVE team has assigned CVE-2026-72343 to this issue. Affected and fixed versions =========================== Issue introduced in 5.17 with commit fa691d0c9c0812b9045f3a9420862e47b3b92518 and fixed in 6.1.178 with commit 3b3a552cf88e10bb7bda88b29cf1fd8267043d50 Issue introduced in 5.17 with commit fa691d0c9c0812b9045f3a9420862e47b3b92518 and fixed in 6.6.145 with commit 5b927dcec5f1087942bf123a82e64a3f66475f01 Issue introduced in 5.17 with commit fa691d0c9c0812b9045f3a9420862e47b3b92518 and fixed in 6.12.97 with commit 22c1d5ecccf92c849bdca1556179aafc95794baf Issue introduced in 5.17 with commit fa691d0c9c0812b9045f3a9420862e47b3b92518 and fixed in 6.18.40 with commit 420aabb32da4381d8d7cdcaa6a77fad9eaceb0a4 Issue introduced in 5.17 with commit fa691d0c9c0812b9045f3a9420862e47b3b92518 and fixed in 7.1.5 with commit abc4c56427f144c96b2827a4db3b90eb5b7349a2 Issue introduced in 5.17 with commit fa691d0c9c0812b9045f3a9420862e47b3b92518 and fixed in 7.2-rc3 with commit 25f6b929c7e379cbea7cb8caa67b49b2d1efae17 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-2026-72343 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/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.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/3b3a552cf88e10bb7bda88b29cf1fd8267043d50 https://git.kernel.org/stable/c/5b927dcec5f1087942bf123a82e64a3f66475f01 https://git.kernel.org/stable/c/22c1d5ecccf92c849bdca1556179aafc95794baf https://git.kernel.org/stable/c/420aabb32da4381d8d7cdcaa6a77fad9eaceb0a4 https://git.kernel.org/stable/c/abc4c56427f144c96b2827a4db3b90eb5b7349a2 https://git.kernel.org/stable/c/25f6b929c7e379cbea7cb8caa67b49b2d1efae17