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 D9C0E58FD0C for ; Fri, 11 Sep 2026 20:01:42 +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=1789156913; cv=none; b=EvkKXlMGNMvOIggoPVvpFiYVSR2epCCZK+p80fwaErWMSEjsOTu/HqID5cUBYqh938BIiP0GlwQqwfoy5US56oTkU3CV3hYNNAEjpE4b6z8vzAGCl6us1Z3amXP/2E6FJg959KO5tXTsQF+OmSikPKpcC++Xa1L2Oz2f1YX9SjE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156913; c=relaxed/simple; bh=luMifLYVnG3cb4mpLcLWiGjcrfy21qNyfYU+2kwx1Xc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ciPGa56MnSpvcCrTtbpRHwOH3jg21i72q+ZFiz8NoaaVGkBjRWZnhEV6JSyvesyzeI3mMP9ZseleXtTvICWfBlW6slxJzW5AUy/OwgFq/YcwGwvTgAuOc0ADyP9PyT2s8bowT5Bhzi/Rrg0b3w64kKpYlQwb7nuRwo8HXzwMXsA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=eXSHhqgN; 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="eXSHhqgN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E147B1F00893; Fri, 11 Sep 2026 20:01:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156901; bh=a+WyKuPFM9lowyQmwa/dS/B+T3d8OMAvDzzj7gxpftk=; h=From:To:Cc:Subject:Date:Reply-To; b=eXSHhqgNGwBXlLGNlojMwii4XzjFuRCmkcTn7fTLEXBQMrKuWjY6cLvdNqcmu3CV3 TpgWhB3TIzRs7k2++BWaNqwTnGb0c9Jwm6a5yhsIHI47xxYXP7i4oWfojSZjo+IHTP xxchODva4Lbp19+qgC4jMXwcbVC3NPKxHsO8nq6k= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89663: nfsd: revoke copy-notify stateids before dropping their reference Date: Fri, 11 Sep 2026 21:45:52 +0200 Message-ID: <2026091147-CVE-2026-89663-0c7f@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=3971; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=vTOicaClqhPYQG2w+9FYQEuu90dcLZfxc950q+9WjXE=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIqs33Dy2b9V6SZvcFearDcpvBX5zutHPLLe22eNs2 6dp+deyOmJZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAiRqkM80uE3Qt+speKL3q1 suRy3e1DM13+KDDM4Yh6kWHGvv7fwVNVHdVm0Z1b1zGdBQA= 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: nfsd: revoke copy-notify stateids before dropping their reference Copy-notify stateids live in the s2s_cp_stateids IDR and on their parent stid's sc_cp_list, pinned by a single membership reference. _free_cpntf_state_locked() only unlinks an entry once its refcount reaches zero, so any revoke path that runs while a concurrent find_cpntf_state()/manage_cpntf_state() holder has elevated cs_count drops the reference without unlinking, leaving the entry discoverable with its membership reference already consumed. A second revoke or a laundromat tick then frees it while the reader still holds the pointer -- a KASAN-detectable use-after-free at the reader's nfs4_put_cpntf_state(). This affected all three revoke paths: - The parent-stid drain (nfs4_free_cpntf_statelist()) repeatedly called _free_cpntf_state_locked() on the first list entry; a holder that had bumped cs_count made it return early, so the next iteration re-decremented and burned the holder's reference. - OFFLOAD_CANCEL (manage_cpntf_state()) and laundromat expiry likewise used _free_cpntf_state_locked() and could drop 2->1 without unlinking. Add revoke_cpntf_state_locked(), which unhashes the entry from the IDR and sc_cp_list first (deferring the final free to any holder), and use it from all three revoke paths. The drain now walks with list_for_each_entry_safe() and revokes each entry unconditionally, so it terminates in one pass per entry regardless of cs_count. The unhash is gated on !list_empty(&cps->cp_list); the idr_remove() gate matters because idr_alloc_cyclic() may have recycled the so_id by then. Keep _free_cpntf_state_locked() for the reference-holder put path only, where a concurrent revoke may already have unlinked the entry (its list_del_init() then a no-op). The Linux kernel CVE team has assigned CVE-2026-89663 to this issue. Affected and fixed versions =========================== Issue introduced in 5.6 with commit 624322f1adc58acd0b69f77a6ddc764207e97241 and fixed in 6.12.109 with commit 6b8149448cdcb476fba4559d1ecc247efee9971b Issue introduced in 5.6 with commit 624322f1adc58acd0b69f77a6ddc764207e97241 and fixed in 6.18.50 with commit b56d2c5f01cddbeca7d11cce81d97db4ec9a464f Issue introduced in 5.6 with commit 624322f1adc58acd0b69f77a6ddc764207e97241 and fixed in 7.2.4 with commit ff8a3cff02b92b2a82f1a9876038fcf953ae9c25 Issue introduced in 5.6 with commit 624322f1adc58acd0b69f77a6ddc764207e97241 and fixed in 7.3-rc1 with commit 3b0c3595db99bb4bebd7c8aa8a36f3c50e411bb7 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-2026-89663 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: fs/nfsd/nfs4state.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/6b8149448cdcb476fba4559d1ecc247efee9971b https://git.kernel.org/stable/c/b56d2c5f01cddbeca7d11cce81d97db4ec9a464f https://git.kernel.org/stable/c/ff8a3cff02b92b2a82f1a9876038fcf953ae9c25 https://git.kernel.org/stable/c/3b0c3595db99bb4bebd7c8aa8a36f3c50e411bb7