From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793831760; b=MB11lYKQNx32b6MPmYYK0Kfh+KWTpvsDcuWx7CW0JECyQ5Py9cwvr+bqeVCp3IZF3E98 4H4880aWIdvR6dK4GXUrRcTdxPYdYmAn9GtZJgK1YpUF/Q6CNBimPC8k9fDkaqlaAtEo0 UWdiiZ3a9TDEIMbZ9+Fb5Qhiz1BYHD+bsxQdkSAf6Mkjhve1VoXUiN61sO9DNpnnADKnA U72tt2Vj1lvpU7C9ZrPjfVAZQx4khyQ8701y/ZRjztWnp2b0takF7OYMwzBaBXUY4MQoq f7QJv6htwgQ/JxTyG44idFkguPbBI1ZSASoCqR3aSty/UD0el8UYZKGz28Z84kM7QWA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831760; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=zQw7x93FI4XdwbZFOsj1NHAcrjlbqfEnXoJqWJ+PG6Y=; b=TI1kGsOOwY/73yQa7vdvFEUOLFXRkLDxrNuq0B6Jf3sK96SW0KQG4BUfhkNUcmzXFHwF ZoGwl2o+7jrSaiUKmimeAGAnkiPqWUEOeNv+EhPC8t1a2AfcEJ1grbcFwhsLPpTrOoVR5 sxPvWtMVeHn3VLb6/zHdxqbApkxZyCHERzTHQ81C2PM7wfYq7hCuuBf8UVQoLpmoEAjiU eeTjqWwfJSnNzlb/ASgc1vhuTsBV0ltXNwnfgmX9SHoKqKgU5lh7xqOFDuLiDGe/975FN b1oD0HFLqalAAF2DUdwsrArhn4yPyj0ScHPIMOJ5ze/r7Xf1Aoqfcku/QQfZbIyhIiw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="sfVqeog/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C2103606A31B; Wed, 4 Nov 2026 22:35:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=sfVqeog/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BE311F00919; Wed, 4 Nov 2026 22:35:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831759; bh=zQw7x93FI4XdwbZFOsj1NHAcrjlbqfEnXoJqWJ+PG6Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=sfVqeog/xxaYCcYjC7BfT4FqVmfFq1X6/cRTa+YARGHNuqV6pQ8QlkGnT9nfCnhWl bIUlM2acdzb9xZGK5vuf/KhscU0ErG2lY2CKHhNX4bDKzH+c/Ir5XcGlEkQjYHhyJ+ BBuhqECqP2Ko5N2nQ246+mWxjKOmDLhzakQuMvyo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Xiang Mei (Microsoft)" , AutonomousCodeSecurity@microsoft.com, "Cen Zhang (Microsoft Security FORGE Labs)" , Chuck Lever Subject: [PATCH 6.18 0895/1005] nfsd: hold cl_lock in client_has_openowners() Date: Wed, 4 Nov 2026 16:10:28 -0500 Message-ID: <20261104211108.280736744@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cen Zhang (Microsoft Security FORGE Labs) commit 5336899b5491eaa2ac22c2925d87daab2b140eb3 upstream. client_has_openowners() walks clp->cl_openowners and reads so_stateids without clp->cl_lock. nfs4_put_stateowner() unhashes that openowner under cl_lock and then frees it, so a concurrent EXCHANGE_ID with mismatched creds can use-after-free the nfs4_openowner. BUG: KASAN: slab-use-after-free in client_has_state+0x10a/0x140 fs/nfsd/nfs4state.c:3718 client_has_openowners() nfsd4_exchange_id nfsd4_proc_compound nfsd_dispatch svc_process Take clp->cl_lock while client_has_openowners() walks the openowner list. Fixes: 4eaea1342507 ("nfsd: improve client_has_state to check for unused openowners") Cc: stable@vger.kernel.org Reported-by: Xiang Mei (Microsoft) Cc: AutonomousCodeSecurity@microsoft.com Signed-off-by: Cen Zhang (Microsoft Security FORGE Labs) Link: https://patch.msgid.link/20260828041925.36758-1-blbllhy@gmail.com Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/nfs4state.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -3759,12 +3759,18 @@ nfsd4_set_ex_flags(struct nfs4_client *n static bool client_has_openowners(struct nfs4_client *clp) { struct nfs4_openowner *oo; + bool found = false; + spin_lock(&clp->cl_lock); list_for_each_entry(oo, &clp->cl_openowners, oo_perclient) { - if (!list_empty(&oo->oo_owner.so_stateids)) - return true; + if (!list_empty(&oo->oo_owner.so_stateids)) { + found = true; + break; + } } - return false; + spin_unlock(&clp->cl_lock); + + return found; } static bool client_has_state(struct nfs4_client *clp)