| From c44899ba9c8fa06158d9bca54e31f4d29c17dacd Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 14 Dec 2022 23:11:58 -0700 |
| Subject: skbuff: Account for tail adjustment during pull operations |
| |
| From: Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com> |
| |
| [ 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 <quic_stranche@quicinc.com> |
| Signed-off-by: Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com> |
| Reviewed-by: Alexander Duyck <alexanderduyck@fb.com> |
| Link: https://lore.kernel.org/r/1671084718-24796-1-git-send-email-quic_subashab@quicinc.com |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/core/skbuff.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| diff --git a/net/core/skbuff.c b/net/core/skbuff.c |
| index 5dcdbffdee49..0186fbe06281 100644 |
| --- a/net/core/skbuff.c |
| +++ b/net/core/skbuff.c |
| @@ -1693,6 +1693,9 @@ unsigned char *__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 |
| |
