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=1793207713; b=zfi0uUNK3w71VQIiLTekhiyM4dOwkViEKIK4nkjdpTfonAAyAarPgFNGmUd9cWZb/+tv twrRKcFeJGy8HXoocqtV3wNHz7T5tDbEIv/mat0NAPGGYQ4UGhyWwRZWBfK266wQDbvkk Aai9UD1iEdrA7OoyknVreDgArOEffAsqE535j+WyJnA4dx7OYDhyQwcArtlVe9F9YOvBG zvzucs0gW6pUfDx1CnKXje3EgHGtODr1+xlBAS/hAvfTiSyjXI0Ax+YQElm8xJBWIZjg4 wPanVyGbBNhAiurdxmHw49ONvNUzenJ6swqW8eQ38/4ytllndxugtmcaW+EKafyL3Tw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793207713; 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=lnKoXyGVxrc5j/gzGxnniyUSHk5VwAV1BBI2yVbBQSA=; b=a6D9ghMoj55sitjgONdLG7xvp2S5z4oHg5NKO0DcDMhNsysreOWbm0ApIzWOyPJpLGz8 4Kexzc9D+wwHYFKBpXn+aKtGlbdcUryVv1wS6tRp0E1gIsHCyH8IAeD79+6kcczB5gWZE 1GxdiISacj722LjHh5+Af7k4HTt7zT+96TE2KZFoNkTA8f3cK28qbrBGRi1PglWP3/PpA a61jTivlnS0e4poMzPUm8OYpd018kQdWcLtDT9shlQjSwzTa1lPOD5UL/LhVZTq6cuKWo h3BY/BUzL2aQSvukOn8PNI5Lr3McPwgGe800406SP50NcNhS6sYX83AMz0SSJU9AnhQ== 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="Z7/UjCp0"; 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 49DAE606A335; Wed, 28 Oct 2026 17:15:13 +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=Z7/UjCp0 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98FDF1F031E8; Wed, 28 Oct 2026 17:15:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793207713; bh=lnKoXyGVxrc5j/gzGxnniyUSHk5VwAV1BBI2yVbBQSA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Z7/UjCp0mXBgGGJCdmxVW13UZylVQybZrZpM/V6H3SnpeXHAZjcloyUQktnGqtugb p1U7JaUeELhCrMJgAK0/xgUcNgwhdcTkxiykbfHnTzdRzU/zjLFd/sGjpazLfTmhmX 2Aab4z4L/ORhhEJbCgwccDnURxicKo6wXpXmqseQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Aswin Karuvally , Jakub Kicinski Subject: [PATCH 6.12 112/247] s390/ctcm: Prevent XID null dereference Date: Wed, 28 Oct 2026 17:58:35 +0100 Message-ID: <20261028165950.051545834@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165947.349197979@linuxfoundation.org> References: <20261028165947.349197979@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 6.12-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;