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bpf: tcp: Do not limit cb_flags when creating child sk from listen sk

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The commit 0813a84156 ("bpf: tcp: Allow bpf prog to write and parse TCP header option")
unnecessarily introduced bpf_skops_init_child() which limited the child
sk from inheriting all bpf_sock_ops_cb_flags of the listen sk.  That
breaks existing user expectation.

This patch removes the bpf_skops_init_child() and just allows
sock_copy() to do its job to copy everything from listen sk to
the child sk.

Fixes: 0813a84156 ("bpf: tcp: Allow bpf prog to write and parse TCP header option")
Reported-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201002013448.2542025-1-kafai@fb.com
This commit is contained in:
Martin KaFai Lau 2020-10-01 18:34:48 -07:00 • committed by Alexei Starovoitov
parent 48ca6243c6
commit 82f45c6c4a
2 changed files with 0 additions and 34 deletions
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33
include/net/tcp.h
View file

@ -2228,34 +2228,6 @@ int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
#endif /* CONFIG_NET_SOCK_MSG */
#ifdef CONFIG_CGROUP_BPF
/* Copy the listen sk's HDR_OPT_CB flags to its child.
*
* During 3-Way-HandShake, the synack is usually sent from
* the listen sk with the HDR_OPT_CB flags set so that
* bpf-prog will be called to write the BPF hdr option.
*
* In fastopen, the child sk is used to send synack instead
* of the listen sk. Thus, inheriting the HDR_OPT_CB flags
* from the listen sk gives the bpf-prog a chance to write
* BPF hdr option in the synack pkt during fastopen.
*
* Both fastopen and non-fastopen child will inherit the
* HDR_OPT_CB flags to keep the bpf-prog having a consistent
* behavior when deciding to clear this cb flags (or not)
* during the PASSIVE_ESTABLISHED_CB.
*
* In the future, other cb flags could be inherited here also.
*/
static inline void bpf_skops_init_child(const struct sock *sk,
struct sock *child)
{
tcp_sk(child)->bpf_sock_ops_cb_flags =
tcp_sk(sk)->bpf_sock_ops_cb_flags &
(BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG |
BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG |
BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG);
}
static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops,
struct sk_buff *skb,
unsigned int end_offset)
@ -2264,11 +2236,6 @@ static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops,
skops->skb_data_end = skb->data + end_offset;
}
#else
static inline void bpf_skops_init_child(const struct sock *sk,
struct sock *child)
{
}
static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops,
struct sk_buff *skb,
unsigned int end_offset)

1
net/ipv4/tcp_minisocks.c
View file

@ -548,7 +548,6 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
newtp->fastopen_req = NULL;
RCU_INIT_POINTER(newtp->fastopen_rsk, NULL);
bpf_skops_init_child(sk, newsk);
tcp_bpf_clone(sk, newsk);
__TCP_INC_STATS(sock_net(sk), TCP_MIB_PASSIVEOPENS);