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| author | Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com> | 2022-12-14 23:11:58 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-12-16 21:18:58 -0800 |
| commit | 2d7afdcbc9d32423f177ee12b7c93783aea338fb (patch) | |
| tree | ef275c6ef0a7c083be4a0e70bcb4a38feb107a57 /net | |
| parent | 214964a13ab56a9757d146b79b468a7ca190fbfb (diff) | |
| download | lwn-2d7afdcbc9d32423f177ee12b7c93783aea338fb.tar.gz lwn-2d7afdcbc9d32423f177ee12b7c93783aea338fb.zip | |
skbuff: Account for tail adjustment during pull operations
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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/skbuff.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 3cbba7099c0f..4a0eb5593275 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2482,6 +2482,9 @@ 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. :-( */ |