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 6B2551E98EF; Sun, 7 Jun 2026 10:13:20 +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=1780827201; cv=none; b=CYID41OesOvlyzXuPIuOEgxPyYRpi7e4LYmSnSh8WuEu5H/d2f1I9Lhr8uAwkmI0zW/xfL9FZO9HNIOSdTSt1BscieqY8RqfB2VWcZ9pBFBs3/SXW95dJ1sm26IITvt7qUeJjuajRhjlkQY6R7DgOcH+LerF58ngT9z4Ecqfw+8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780827201; c=relaxed/simple; bh=EAt+AqdO+gWyyXMOV8Wf0u8fX5dTVO1x7MBbJDDFt98=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CKEvf9GEhjMZY6j7jiukjc5Hke6e/sEiDlvrizTmr34wITq5Fhip4FqPYpZNapsK0o65hdF+HUvgugv84iPAQSR8uSq4jfm0N4S/NbtAUla5kKvYID58DEb58TYyehRcW5TLci5PFhkYN6euh0DJFg0L0bfl0RvH+xAaFDBGFfE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=puWoojgM; 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="puWoojgM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9ECE11F00893; Sun, 7 Jun 2026 10:13:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780827200; bh=fzs0t7lUI8FXYnXdhTixQm7dulm4BzxY7wVHGxx9OrE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=puWoojgMAqDe9phd9BI1KQPmJIJN5PcThiUb1frZ2p3aAjRm5tMpNaSm3OUv9Aqzu 3ZBUwwSlxIKl8aD1b6okMiV+MU9j5ty1EfY4ozsJjmm/JrxcpPhKJAm6yO5d5Dzwui HeCfXyYkhSfj1PifaupDgyPEdVmMsGhWFbV8Vh1I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Danielle Ratson , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 049/315] ethtool: cmis: require exact CDB reply length Date: Sun, 7 Jun 2026 11:57:16 +0200 Message-ID: <20260607095729.390836234@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260607095727.528828913@linuxfoundation.org> References: <20260607095727.528828913@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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: Jakub Kicinski [ Upstream commit 6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1 ] Malicious SFP module could respond with rpl_len longer than what cmis_cdb_process_reply() expected, leading to OOB writes. Malicious HW is a bit theoretical but some modules may just be buggy and/or the reads may occasionally get corrupted, so let's protect the kernel. The existing check protects from short replies. We need to protect from long ones, too. All callers that pass a non-zero rpl_exp_len cast the reply payload to a fixed-layout struct and read fields at fixed offsets, with no version negotiation or short-reply handling: - cmis_cdb_validate_password() - cmis_cdb_module_features_get() - cmis_fw_update_fw_mng_features_get() so let's assume that responses longer than expected do not have to be handled gracefully here. Add a warning message to make the debug easier in case my understanding is wrong... Note that page_data->length (argument of kmalloc) comes from last arg to ethtool_cmis_page_init() which is rpl_exp_len. Note2 that AIs also like to point out overflows in args->req.payload itself (which is a fixed-size 120 B buffer, on the stack), but callers should be reading structs defined by the standard, so protecting from requests for more data than max seem like defensive programming. Fixes: a39c84d79625 ("ethtool: cmis_cdb: Add a layer for supporting CDB commands") Reviewed-by: Danielle Ratson Link: https://patch.msgid.link/20260522231312.1710836-7-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ethtool/cmis_cdb.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/ethtool/cmis_cdb.c b/net/ethtool/cmis_cdb.c index 3057576bc81e3d..fe156991d0becd 100644 --- a/net/ethtool/cmis_cdb.c +++ b/net/ethtool/cmis_cdb.c @@ -513,8 +513,13 @@ static int cmis_cdb_process_reply(struct net_device *dev, } rpl = (struct ethtool_cmis_cdb_rpl *)page_data->data; - if ((args->rpl_exp_len > rpl->hdr.rpl_len + rpl_hdr_len) || - !rpl->hdr.rpl_chk_code) { + if (rpl->hdr.rpl_len != args->rpl_exp_len) { + netdev_warn(dev, "CDB reply length mismatch, expected %u got %u\n", + args->rpl_exp_len, rpl->hdr.rpl_len); + err = -EIO; + goto out; + } + if (!rpl->hdr.rpl_chk_code) { err = -EIO; goto out; } -- 2.53.0