From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93FD12E7379; Thu, 28 May 2026 20:27:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780000035; cv=none; b=mp0p25diQO/WIQtSlokAdb53DYrcOQfmWvxZv1iuT8B26b/hgO55wXHW3aXzcEjPQmh0vv/FHf/Bt6FKxf/aGyvUTrIQO83hkFJrZ1GEn1B0gcAyCAVVodSyy8vgLuG8PnKEbui78Xsm+HxGFghB+0nfAWVXMazaWbluTYz8IcI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780000035; c=relaxed/simple; bh=JJvOLt47s883xP3jKJS4Pkf9sHPWvgl+QvZpn9ljvmM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P38V8hJ2tgJ3RdyceP4GAq2614/ERB+61haLGXR03vAaHbJEmejiaAtJqGSF4y6NmnlSxnUCsdJ/3xm5HNgLgvKI+Cn33IEAWMxjkbSV6pA+Ku1BjNn2nTMcCtNBoFrEr1EEl+qU5mU3tWQxfF3R02nxXmDFybKg5rvenr/mIOE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MVUR8yXB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="MVUR8yXB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F36481F000E9; Thu, 28 May 2026 20:27:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780000034; bh=NDUIFfJ2dlj9L7Eq7T72zx/QpquKXMtAeYpHUvpjv3M=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=MVUR8yXBWmMdHX5j7fvPO8uC9zh8d7f33tMAq/yzYxD3Rxq/5cGHv4muUBn1nmwJS 6HPpylvsezkq/d1VWe/fCtVzu1x1hQ6xZrCnI155ywEnK/0sBn29CRVu9pFbn0VTMl RXDiBbwH0zswPj5fRJ6es1IZedT8Ici2KC9OgICs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Xiang Mei , Paolo Abeni , Sasha Levin Subject: [PATCH 6.18 280/377] net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot Date: Thu, 28 May 2026 21:48:38 +0200 Message-ID: <20260528194646.463967140@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260528194638.371537336@linuxfoundation.org> References: <20260528194638.371537336@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit 277740023def559a4a2ddc3e8e784ee37a0f16a9 ] On the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is reserved for an SMC-Dv1 device. smc_find_ism_v2_device_clnt() populates V2 entries starting at index 1, so when no V1 device is selected slot 0 is left in its kzalloc()'ed state with ism_dev[0] == NULL and ism_chid[0] == 0. smc_v2_determine_accepted_chid() then matches the peer's CHID against the array starting from index 0 using the CHID alone. A malicious peer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches the empty slot, ini->ism_selected becomes 0, and the subsequent ism_dev[0]->lgr_lock dereference in smc_conn_create() faults at offsetof(struct smcd_dev, lgr_lock) == 0x68: BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0 Write of size 4 at addr 0000000000000068 by task exploit/144 Call Trace: _raw_spin_lock_bh smc_conn_create (net/smc/smc_core.c:1997) __smc_connect (net/smc/af_smc.c:1447) smc_connect (net/smc/af_smc.c:1720) __sys_connect __x64_sys_connect do_syscall_64 Require ism_dev[i] to be non-NULL before accepting a CHID match. Fixes: a7c9c5f4af7f ("net/smc: CLC accept / confirm V2") Reported-by: Weiming Shi Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Xiang Mei Link: https://patch.msgid.link/20260511062138.2839584-1-xmei5@asu.edu Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/smc/af_smc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 6421c2e1c84de..5915fcdef743d 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -1400,7 +1400,8 @@ smc_v2_determine_accepted_chid(struct smc_clc_msg_accept_confirm *aclc, int i; for (i = 0; i < ini->ism_offered_cnt + 1; i++) { - if (ini->ism_chid[i] == ntohs(aclc->d1.chid)) { + if (ini->ism_dev[i] && + ini->ism_chid[i] == ntohs(aclc->d1.chid)) { ini->ism_selected = i; return 0; } -- 2.53.0