diff options
| author | Yan Zhai <yan@cloudflare.com> | 2023-01-30 12:51:48 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-01-31 21:07:04 -0800 |
| commit | 876e8ca8366735a604bac86ff7e2732fc9d85d2d (patch) | |
| tree | 1811ea6007be8a446e37f283d8015b19d8bc3035 /net/core | |
| parent | efec2e2a722ed609fc7b64feef720fd601633b73 (diff) | |
net: fix NULL pointer in skb_segment_list
Commit 3a1296a38d0c ("net: Support GRO/GSO fraglist chaining.")
introduced UDP listifyed GRO. The segmentation relies on frag_list being
untouched when passing through the network stack. This assumption can be
broken sometimes, where frag_list itself gets pulled into linear area,
leaving frag_list being NULL. When this happens it can trigger
following NULL pointer dereference, and panic the kernel. Reverse the
test condition should fix it.
[19185.577801][ C1] BUG: kernel NULL pointer dereference, address:
...
[19185.663775][ C1] RIP: 0010:skb_segment_list+0x1cc/0x390
...
[19185.834644][ C1] Call Trace:
[19185.841730][ C1] <TASK>
[19185.848563][ C1] __udp_gso_segment+0x33e/0x510
[19185.857370][ C1] inet_gso_segment+0x15b/0x3e0
[19185.866059][ C1] skb_mac_gso_segment+0x97/0x110
[19185.874939][ C1] __skb_gso_segment+0xb2/0x160
[19185.883646][ C1] udp_queue_rcv_skb+0xc3/0x1d0
[19185.892319][ C1] udp_unicast_rcv_skb+0x75/0x90
[19185.900979][ C1] ip_protocol_deliver_rcu+0xd2/0x200
[19185.910003][ C1] ip_local_deliver_finish+0x44/0x60
[19185.918757][ C1] __netif_receive_skb_one_core+0x8b/0xa0
[19185.927834][ C1] process_backlog+0x88/0x130
[19185.935840][ C1] __napi_poll+0x27/0x150
[19185.943447][ C1] net_rx_action+0x27e/0x5f0
[19185.951331][ C1] ? mlx5_cq_tasklet_cb+0x70/0x160 [mlx5_core]
[19185.960848][ C1] __do_softirq+0xbc/0x25d
[19185.968607][ C1] irq_exit_rcu+0x83/0xb0
[19185.976247][ C1] common_interrupt+0x43/0xa0
[19185.984235][ C1] asm_common_interrupt+0x22/0x40
...
[19186.094106][ C1] </TASK>
Fixes: 3a1296a38d0c ("net: Support GRO/GSO fraglist chaining.")
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Yan Zhai <yan@cloudflare.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/Y9gt5EUizK1UImEP@debian
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/skbuff.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 4a0eb5593275..a31ff4d83ecc 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4100,7 +4100,7 @@ struct sk_buff *skb_segment_list(struct sk_buff *skb, skb_shinfo(skb)->frag_list = NULL; - do { + while (list_skb) { nskb = list_skb; list_skb = list_skb->next; @@ -4146,8 +4146,7 @@ struct sk_buff *skb_segment_list(struct sk_buff *skb, if (skb_needs_linearize(nskb, features) && __skb_linearize(nskb)) goto err_linearize; - - } while (list_skb); + } skb->truesize = skb->truesize - delta_truesize; skb->data_len = skb->data_len - delta_len; |