From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9B1BC6FD18 for ; Tue, 18 Apr 2023 12:31:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231630AbjDRMbR (ORCPT ); Tue, 18 Apr 2023 08:31:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231613AbjDRMbD (ORCPT ); Tue, 18 Apr 2023 08:31:03 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D06B9C16C for ; Tue, 18 Apr 2023 05:30:47 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 42001631A9 for ; Tue, 18 Apr 2023 12:30:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5809AC4339B; Tue, 18 Apr 2023 12:30:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681821024; bh=4lD04OAjI3ZG8K6M4vFAQ14rVCyn7UTx7mUU/WP1TE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B4+sczNKytWGRPJB8h3+eRzHgh85QClGxJPGmiaeMOSRfWmyiILcckESf6KxZdQ0N uUkzInTbHMl1IakXdHSkbF8X2mcXzDBos/zagXRcZ679j6qB2sjFC8Sa3WEZeyGYs6 uYqWXQ+wJnq4MbG3sGbKADgrtmvQuj682hYlm+As= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shuangpeng Bai , Oleksij Rempel , Marc Kleine-Budde Subject: [PATCH 5.4 35/92] can: j1939: j1939_tp_tx_dat_new(): fix out-of-bounds memory access Date: Tue, 18 Apr 2023 14:21:10 +0200 Message-Id: <20230418120306.069653726@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230418120304.658273364@linuxfoundation.org> References: <20230418120304.658273364@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Oleksij Rempel commit b45193cb4df556fe6251b285a5ce44046dd36b4a upstream. In the j1939_tp_tx_dat_new() function, an out-of-bounds memory access could occur during the memcpy() operation if the size of skb->cb is larger than the size of struct j1939_sk_buff_cb. This is because the memcpy() operation uses the size of skb->cb, leading to a read beyond the struct j1939_sk_buff_cb. Updated the memcpy() operation to use the size of struct j1939_sk_buff_cb instead of the size of skb->cb. This ensures that the memcpy() operation only reads the memory within the bounds of struct j1939_sk_buff_cb, preventing out-of-bounds memory access. Additionally, add a BUILD_BUG_ON() to check that the size of skb->cb is greater than or equal to the size of struct j1939_sk_buff_cb. This ensures that the skb->cb buffer is large enough to hold the j1939_sk_buff_cb structure. Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Reported-by: Shuangpeng Bai Tested-by: Shuangpeng Bai Signed-off-by: Oleksij Rempel Link: https://groups.google.com/g/syzkaller/c/G_LL-C3plRs/m/-8xCi6dCAgAJ Link: https://lore.kernel.org/all/20230404073128.3173900-1-o.rempel@pengutronix.de Cc: stable@vger.kernel.org [mkl: rephrase commit message] Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- net/can/j1939/transport.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -600,7 +600,10 @@ sk_buff *j1939_tp_tx_dat_new(struct j193 /* reserve CAN header */ skb_reserve(skb, offsetof(struct can_frame, data)); - memcpy(skb->cb, re_skcb, sizeof(skb->cb)); + /* skb->cb must be large enough to hold a j1939_sk_buff_cb structure */ + BUILD_BUG_ON(sizeof(skb->cb) < sizeof(*re_skcb)); + + memcpy(skb->cb, re_skcb, sizeof(*re_skcb)); skcb = j1939_skb_to_cb(skb); if (swap_src_dst) j1939_skbcb_swap(skcb);