From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2F3C879C9 for ; Thu, 12 Jan 2023 14:23:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 876E6C433D2; Thu, 12 Jan 2023 14:23:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673533433; bh=rNQTsYg8sYVv3soKiNAWWlKgR8CqY1vX29xuB3yE4t0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RdIcG4teRL1GOI9lU2lJNn74H9Jz3YjGjzOkrECPuP6TqoCCf2KHplBFPXk0EeW/o GVQ7XG+EAikXmjY/+cfdac6q7+OWgXYzTArYDkGHdbPibvWLtY7MmoE1IzyBnfJmA6 BAq2GgI2TYkIA1HWPCWP52oEj6mEEXzPizGdzJCE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sean Tranchetti , Subash Abhinov Kasiviswanathan , Alexander Duyck , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 477/783] skbuff: Account for tail adjustment during pull operations Date: Thu, 12 Jan 2023 14:53:13 +0100 Message-Id: <20230112135546.312669296@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230112135524.143670746@linuxfoundation.org> References: <20230112135524.143670746@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Subash Abhinov Kasiviswanathan [ Upstream commit 2d7afdcbc9d32423f177ee12b7c93783aea338fb ] Extending the tail can have some unexpected side effects if a program uses a helper like BPF_FUNC_skb_pull_data to read partial content beyond the head skb headlen when all the skbs in the gso frag_list are linear with no head_frag - kernel BUG at net/core/skbuff.c:4219! pc : skb_segment+0xcf4/0xd2c lr : skb_segment+0x63c/0xd2c Call trace: skb_segment+0xcf4/0xd2c __udp_gso_segment+0xa4/0x544 udp4_ufo_fragment+0x184/0x1c0 inet_gso_segment+0x16c/0x3a4 skb_mac_gso_segment+0xd4/0x1b0 __skb_gso_segment+0xcc/0x12c udp_rcv_segment+0x54/0x16c udp_queue_rcv_skb+0x78/0x144 udp_unicast_rcv_skb+0x8c/0xa4 __udp4_lib_rcv+0x490/0x68c udp_rcv+0x20/0x30 ip_protocol_deliver_rcu+0x1b0/0x33c ip_local_deliver+0xd8/0x1f0 ip_rcv+0x98/0x1a4 deliver_ptype_list_skb+0x98/0x1ec __netif_receive_skb_core+0x978/0xc60 Fix this by marking these skbs as GSO_DODGY so segmentation can handle the tail updates accordingly. Fixes: 3dcbdb134f32 ("net: gso: Fix skb_segment splat when splitting gso_size mangled skb having linear-headed frag_list") Signed-off-by: Sean Tranchetti Signed-off-by: Subash Abhinov Kasiviswanathan Reviewed-by: Alexander Duyck Link: https://lore.kernel.org/r/1671084718-24796-1-git-send-email-quic_subashab@quicinc.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/skbuff.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 176bcbb07aab..2b12e0730b85 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2115,6 +2115,9 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta) insp = list; } else { /* Eaten partially. */ + if (skb_is_gso(skb) && !list->head_frag && + skb_headlen(list)) + skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; if (skb_shared(list)) { /* Sucks! We need to fork list. :-( */ -- 2.35.1