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=1793210102; b=BLUQZQQB/NP5SUJSD3j2VvzIArqoHOlpOkO2RPnARFg0isnNcioi8VDAVvxtJ23adjXC dPc+X+VZMmcKzwjOahSOnkQOfABO8Ehh+3WfJNMvUKGUuiW3Hxu3OptRKRN4OJC7ZeQLo pMtl9zk32/p2EYPt3C9U6o69r4dLCS4olIqtovZWc/PkY4EKIVVmLHUq7jYghxN7gjL/Q 9RY4V6ahbKt1dq+5qwvFjyDyarOzaHa/Rcphyx9cj8v4YDzbE9CNxmm5AbO9eaYISUCZl I9RcsQH8uZ3wpMasnHlq+GyVZOifFm5LD2ATg2iS7uaPmvXtYGvnYMB5PZJm3nPVZ1Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793210102; 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=ix5qKRpS47xNU5dLszbh5fMDUvF0T0Ms7zywr+w/IAA=; b=hBpX9rZRWnALdI3kwCEGAdKUDVfulfQKVV/p77aCFtnnWd6g6sO54wBASGP89FdvGDiF Gvu4IIDYUdMQKND+lquUlgCN0ZI6YzQLnDc/CZssnb/qZBDc8178Lmpw1uSoc85FaQQSJ tg4oH3OsCACJZYeQEbtHWZ7LDe/owCaMcrIi6dC2kjsvww7Lq7zup7GRcRg7sjk/Qz9wN oIoi976ufGNZENL2aFuodTVr1u0gyQj262TolpL1TpM8JcBvvrMzQAZDbTNL8LUwIm80C +hgIr9g768YrmhUxyZf0shalVnGSO8a6diPBYY8qlZUNdPTU4iT5tWZydWh0hVICR0A== 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=rN0qzjeW; 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 4F9DC606A31C; Wed, 28 Oct 2026 17:55:02 +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=rN0qzjeW Received: by smtp.kernel.org (Postfix) with ESMTPSA id CBF911F01825; Wed, 28 Oct 2026 17:55:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793210102; bh=ix5qKRpS47xNU5dLszbh5fMDUvF0T0Ms7zywr+w/IAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=rN0qzjeWnRvRY/qwrM8t/J6F0aB4InNVbAprAobwvoGqxR3pxd3N0uPD162b8LlFv mM74mFyQL7fzAAkIUXLISW2BWsgin4MWTCbd5uNRuz0FdLwOk8pw7t9RfHYBoVs6v8 er5E/LWUqwjq9aM0xzaaS6X7h0x5UxIaHtRtm3qY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Aswin Karuvally , Jakub Kicinski Subject: [PATCH 6.6 077/168] s390/ctcm: Prevent XID null dereference Date: Wed, 28 Oct 2026 18:00:13 +0100 Message-ID: <20261028165944.907406753@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165943.089486480@linuxfoundation.org> References: <20261028165943.089486480@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Aswin Karuvally commit b264d8422779d69febce914efc47a92a85cc382c upstream. The mpc_validate_xid() function sets grp->saved_xid2->xid2_flag2 to 0x40 to signal XID validation error. If peer XID is NULL or r/w channel pairing mismatch happens, grp->saved_xid2 is never initialized. An attempt to set the flag in such case leads to NULL dereference. Fix this by using the always available priv->xid->xid2_flag2 instead of grp->saved_xid2->xid2_flag2 for validation errors. Fixes: 293d984f0e36 ("ctcm: infrastructure for replaced ctc driver") Cc: stable@vger.kernel.org Signed-off-by: Aswin Karuvally Link: https://patch.msgid.link/20260827063408.2168914-1-aswin@linux.ibm.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/s390/net/ctcm_mpc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/s390/net/ctcm_mpc.c +++ b/drivers/s390/net/ctcm_mpc.c @@ -826,7 +826,7 @@ static void mpc_action_go_ready(fsm_inst fsm_deltimer(&grp->timer); - if (grp->saved_xid2->xid2_flag2 == 0x40) { + if (priv->xid->xid2_flag2 == 0x40) { priv->xid->xid2_flag2 = 0x00; if (grp->estconnfunc) { grp->estconnfunc(grp->port_num, 1, @@ -1636,7 +1636,6 @@ done: "The XID used in the MPC protocol is not valid, " "rc = %d\n", rc); priv->xid->xid2_flag2 = 0x40; - grp->saved_xid2->xid2_flag2 = 0x40; } return rc;