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=1792774268; b=n936XL9lwP8lmhkur7xB5JxKMI4yZ86K7N84d/wTQgr3bh9DB2zLgRMKiHHKfgmQZUjU BoncU8ww+h/iidyS3WkC0wrryYvFMOokNmABT2DL6bxJ5koXWOon0+5wXQQMRJP9OwCZz 91K2lrDEpr9jb7+6d0B8XDqI55cZ4fv5E5X2pVfyosagkveYktYuWuwJ++pFi4l6wFEIO OahhkXLcJVhG/xgUDsIuPZSVoZjDzMO6zuoOwGlkYQE8xlvaoXbqpbYhST3zuvAHo+8f0 lCbOGqcNpl9Z/BNEpcAZ1EPkNUSJiT8iVMZSAzbuEi8utJuJ9yKKg7AQTdyIx8ecchg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774268; 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=yxN4heFFK0dHkPTfyYHikIG1D8uHn7AIdaCXgjaHZPY=; b=Va5Yk6+yPiRRJF6G7H3UYuvNk6hsM5uSNZVZzPnqpxXiQVnUz0Ga3GqC3fjFtwXKrUdW wcVS7Pkt3tCDC8i60NsOLFqlee85ziOZhiTp3r8ZrYlLBkEdyjNmbDeId0RFhUA/VehRo lDrf7dAn0hkvHUpg/7zkzD7aiCvV2KMjvU6SRTEDSxAiedqGq1o96Ww8yI54fh6Tenwe+ vZ7jdDnVGB3X3uuZG5fdjROrJ/QzF5cjqzVn6UfzRBQ4QZTvSV3Qxhb1fuNuatdBtINQx exC9TmVz0n0h8A1lC2tvZM09Q3/XsRbVLcrwAfFR3FbTeywnDkZl/kDCDlaU9jL8k/A== 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=Dl+hrW5p; 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 CFBFD606A31A; Fri, 23 Oct 2026 16:51:07 +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=Dl+hrW5p Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C2491F01825; Fri, 23 Oct 2026 16:51:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774267; bh=yxN4heFFK0dHkPTfyYHikIG1D8uHn7AIdaCXgjaHZPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Dl+hrW5pTyA9E7LqUT2YL4Ex5l4K+4/OvaPYWYAJHhclx6HTkZHtUjE9rx6zb2hiU 7AueEMzhY03xUNhx0y9qywHi1R++pO8uYNHds8nhlYsCDdrDNlIpWOzm4vMznempht Y4XG1iFVY75NdALQpmtRxCC1sqBN9uRJAJhpLyf0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Aswin Karuvally , Jakub Kicinski Subject: [PATCH 6.18 139/193] s390/ctcm: Prevent XID null dereference Date: Fri, 23 Oct 2026 18:36:56 +0200 Message-ID: <20261023163717.495796608@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163714.201276352@linuxfoundation.org> References: <20261023163714.201276352@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: 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 @@ -827,7 +827,7 @@ 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, @@ -1637,7 +1637,6 @@ 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;