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=1793209560; b=vULzmfTW5+ZaZw281w9fcgu4MOKWtHPZhpGg2VSd4uzPi8d5HiSXxvt7C96/r879i266 HaFXOobTpBon9r2CmqGxJj+lALGbfcXdrcxTfwtp7Xqo5U0Yj6SLmXwnxkqm4j72YdB32 3HDcZgUbRKRbZFBdS8+N/mD6GwS7dSYhRw2xF+MRxlEbjFI6wnIvYD6porqIDuhjuerD2 ycMdYjX2QKnF3XpPx2mFCdX9M/aH+6BKLwp34W1BWadnRe+WuzC39rLQcPMkEhTHWzWd7 oJ0kHSJjME9fuqOptlX30TrREJAoflTRyrfJll43ySS4gFGUtB51Zpdf4fR41AAA8xQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793209560; 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=Vtt69r2od9Gu0CcXenq4/oMZgkz2IjeUKZF5xNsJXyA=; b=s5ndpDbcLPLlHj2WXyjsq/OllOjhnDl1XOcXeruJBOD76TnPU6K5UU0z3mAxFm67qsuE xaLxscDovSMzIlPrPelWTrLipaKNcs4rh1JWwmzAugXEVjRN6FE3ljwifz2+dSlSKeJAG CD+n28QBm8GzMJIj0UZKHY8yUPMflPInJmvN9xS0DZelFknIlmua7+vY4gISZPKUxRI4B lXlFCsTNRLd3P+AeJ8ATxYZ3WeSrk+nI3ddHNjrczgOW9jY28VaoVwQ1PyUCaZ683LyZ5 5MEF26VhOllCfZdwuWcHwWaZyd0R96oT0FEC8HGm+2KaDnzkrO/nUhGESBOCZrT7p1g== 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=FZgNRBGs; 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 5F202606A31C; Wed, 28 Oct 2026 17:46:00 +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=FZgNRBGs Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6352D1F01825; Wed, 28 Oct 2026 17:45:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793209559; bh=Vtt69r2od9Gu0CcXenq4/oMZgkz2IjeUKZF5xNsJXyA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FZgNRBGsO6QmfiJnDNWnubMQubtMjzdfo+DkJrEUJakxGPxENBtQvDYytl4pYRc0U ZCEXIbyJBOKOUpxgM9TiAkhjtTSij6Gz/tm+1Af9aCPgmVh2x5N5fRjvN4lOyxlfQK tFEr7SpX3BtHsQOKaAlNhLDCAIC1dNnVOtq69bls= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Aswin Karuvally , Jakub Kicinski Subject: [PATCH 5.10 471/516] s390/ctcm: Prevent XID null dereference Date: Wed, 28 Oct 2026 18:00:23 +0100 Message-ID: <20261028170014.638951323@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170003.522232767@linuxfoundation.org> References: <20261028170003.522232767@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 5.10-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 @@ -838,7 +838,7 @@ 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, @@ -1647,7 +1647,6 @@ 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;