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 3CA8A4DEC29 for ; Thu, 17 Sep 2026 16:14:36 +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=1789661678; cv=none; b=juWOGUx5TBZql+gOLbrJXjxvvo4b9osn1RHlrpLZry+xdT0l7MaPPQcK2OAZGkNn0r4MyFpRQBL4td3WxaU8hAwxKELl2jf95q3aNUlF/Io1Tz5+lGggjXEVap6aWGFMmfCcw1TLzMW/2J3tDNVjeI65eROVy29trFfJrgIUhjY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789661678; c=relaxed/simple; bh=gtpiDGf20SwhrbXm7hV+xrZ1wbPCuhfGdBeB1fNDIvk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=tgw+hg+lZ0gBisV8tih02jektbTjcgfjshBU8B6SJz5r8wQ6aO+ayVd3qN2JYoaVY1VZZzQ3rH3FNluoPljk3SE2/bmU3A31OPkT8Qo6tQQQK7OPPYErEiUadXbBnipeu/HpKtdrBnTLZ4/9N7JVmw7Vz70e1+thnx0f/ddvSlE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=stJQH/Ty; 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="stJQH/Ty" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F7351F000FF; Thu, 17 Sep 2026 16:14:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789661675; bh=cK8WkaLU3v0f57ddgdg1JYx0eMYAAVigKsrbd3hzZuY=; h=From:To:Cc:Subject:Date:Reply-To; b=stJQH/TyJ+sRC0bmi7BV0zthoOBjm/HxCeTyr8n4bbJq53F+790TM+ASVXKRquw/A jpikF7Y/3ItvhtKhfkICOPYPCtbKFDfhA1HOQ5nLg2/HDso1E0IEfoxdTz6KNLWOYz oaTcBh4+cTnBxLcVwKdLZ4bNFHwlhOpPDBfRUEYg= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-90100: ptp: netc: fix period truncation and potential divide-by-zero in PEROUT Date: Thu, 17 Sep 2026 17:08:50 +0100 Message-ID: <2026091713-CVE-2026-90100-63f2@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=3269; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=abFx3aOe37bNBC47eQKtGU8W/UBEUsuh/G6wD/QUj6g=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlrBHJj7guLZS+z1LWWEHhj1nX51de385l/KWqHJknHH Y6dN8WjI5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACZy9RjDbHZGz9iDE76/3qfF /3nGc5l7BwMifBjmu8bvexeXplbzaa0Zo/pm+SerOP7zAgA= 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: ptp: netc: fix period truncation and potential divide-by-zero in PEROUT The max_period bound in net_timer_enable_perout() was computed as: max_period = (u64)NETC_TMR_DEFAULT_FIPER + integral_period; which exceeds U32_MAX when integral_period > 0 (e.g. 0x100000002 for the default 333333333 Hz clock). A period_ns that passes this check but exceeds U32_MAX is then silently truncated when stored into the u32 struct netc_pp::period field. A truncated value of zero can reach netc_timer_set_perout_alarm(), where the local u32 period variable would also be 0, causing a divide-by-zero in roundup_u64(delta, period) whenever the stime < min_time branch is taken (which always happens for a start time of {0, 0}). Additionally, netc_timer_enable_periodic_pulse() and netc_timer_enable_fiper() both compute: fiper = pp->period - integral_period; A zero pp->period results in an unsigned wraparound to 0xFFFFFFFD, mis-programming the FIPER hardware register. Fix all three issues by capping max_period at NETC_TMR_DEFAULT_FIPER (0xFFFFFFFF). This ensures that any period_ns passing the range check fits in a u32 without truncation, so the stored value is always valid and non-zero. The accepted range is reduced by integral_period ns (typically only a few nanoseconds), which is negligible in practice. The Linux kernel CVE team has assigned CVE-2026-90100 to this issue. Affected and fixed versions =========================== Issue introduced in 6.18 with commit 671e266835b8a87d6cc2c6db962de23783405dd8 and fixed in 6.18.52 with commit 51fe3fe0ffec033bd831c71d9bee3dee827e491c Issue introduced in 6.18 with commit 671e266835b8a87d6cc2c6db962de23783405dd8 and fixed in 7.2.6 with commit 08988d1941e180f0ad30d91233cb64f3418ba23c Issue introduced in 6.18 with commit 671e266835b8a87d6cc2c6db962de23783405dd8 and fixed in 7.3-rc1 with commit 777dbc9914b2f003f1d44af80c7a4a395c5961b2 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-2026-90100 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/ptp/ptp_netc.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/51fe3fe0ffec033bd831c71d9bee3dee827e491c https://git.kernel.org/stable/c/08988d1941e180f0ad30d91233cb64f3418ba23c https://git.kernel.org/stable/c/777dbc9914b2f003f1d44af80c7a4a395c5961b2