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 C449A2AD00; Sun, 7 Jun 2026 10:16:49 +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=1780827410; cv=none; b=SQLwkXS+ZQ+4qy+eOSwlZMn5sefM5vts9ge2KIGzdcbvHhVe9B1REM1/Bof2LcRsLM5u7D8kMlALerczFFemuTSzQyjIj2mySjxwCEe7icsxthzj+nrpg37AfhLcrebjk6rOvwTZudPYMfI/1EebRPUzceUdHSnfuVnwBc5Ly88= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780827410; c=relaxed/simple; bh=WwCEJ8x7tWMI6fDwUUjdtrSFYhYqgOH8yMIt0ncNSK8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NU3TiHQvBd8zTE+XCG60JU9Yolh64uAPOs+QgPaKJktDBOc5bqB7gbfRjoGb83nxWH4FTF5QAqlaCpgVmESQCfX4K96keZxzzZflrfhP6r4GIE6dDEZEIKpVPeIeaveFXAJivf3IzObWVWfZPWS9a9qBLwnzRU+t/S6nUF/qBXA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UqMqqPT8; 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="UqMqqPT8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FC231F00893; Sun, 7 Jun 2026 10:16:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780827409; bh=Jq+BmpWYD/hAikipeathwnNTJpRjAItpO43kFmdx5SU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UqMqqPT8l7ecS8gmENFTJPq4rmG88mLKSIpvzaFhoBoliixbW21MP6uFeIim0/HS7 +T0ZBxpGtofPCaYTEeSeKKc5zSrko5oSnH8W8PUo5kB31ut2Gfvvu6wvcXar6oZ5cf 3peSo5KEM82R0x6WJNGZ3yePBc8eSboIYIidGbAs= 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 6.12 053/307] ethtool: cmis: require exact CDB reply length Date: Sun, 7 Jun 2026 11:57:30 +0200 Message-ID: <20260607095729.670354372@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260607095727.647295505@linuxfoundation.org> References: <20260607095727.647295505@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 6.12-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 8bf99295bfbe96..690002366d965a 100644 --- a/net/ethtool/cmis_cdb.c +++ b/net/ethtool/cmis_cdb.c @@ -508,8 +508,13 @@ 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