This is a note to let you know that I've just added the patch titled
skbuff: Account for tail adjustment during pull operations
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
skbuff-account-for-tail-adjustment-during-pull-opera.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit dcb40af8e3b1b9d2ba09cc454d423f0ad8849d12
Author: Subash Abhinov Kasiviswanathan <quic_subashab@xxxxxxxxxxx>
Date: Wed Dec 14 23:11:58 2022 -0700
skbuff: Account for tail adjustment during pull operations
[ 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@xxxxxxxxxxx>
Signed-off-by: Subash Abhinov Kasiviswanathan <quic_subashab@xxxxxxxxxxx>
Reviewed-by: Alexander Duyck <alexanderduyck@xxxxxx>
Link: https://lore.kernel.org/r/1671084718-24796-1-git-send-email-quic_subashab@xxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 4178fc28c277..7f501dff4501 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1953,6 +1953,9 @@ 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. :-( */
