Commit 440c5752 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'Do not limit cb_flags when creating child sk' 



Martin KaFai says:

====================
This set fixes an issue that the bpf_skops_init_child() unnecessarily
limited the child sk from inheriting all bpf_sock_ops_cb_flags
of the listen sk.  It also adds a test to check that.
====================

Tested-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 48ca6243 96d46c50

include/net/tcp.h

+0 −33
Original line number Diff line number Diff line
@@ -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)

net/ipv4/tcp_minisocks.c

+0 −1
Original line number Diff line number Diff line
@@ -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);

tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c

+12 −0
Original line number Diff line number Diff line
@@ -264,9 +264,19 @@ static int check_error_linum(const struct sk_fds *sk_fds) 


static void check_hdr_and_close_fds(struct sk_fds *sk_fds)

{

	const __u32 expected_inherit_cb_flags =

		BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG |

		BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG |

		BPF_SOCK_OPS_STATE_CB_FLAG;



	if (sk_fds_shutdown(sk_fds))

		goto check_linum;



	if (CHECK(expected_inherit_cb_flags != skel->bss->inherit_cb_flags,

		  "Unexpected inherit_cb_flags", "0x%x != 0x%x\n",

		  skel->bss->inherit_cb_flags, expected_inherit_cb_flags))

		goto check_linum;



	if (check_hdr_stg(&exp_passive_hdr_stg, sk_fds->passive_fd,

			  "passive_hdr_stg"))

		goto check_linum;
@@ -321,6 +331,8 @@ static void reset_test(void) 
	memset(&skel->bss->active_estab_in, 0, optsize);

	memset(&skel->bss->active_fin_in, 0, optsize);



	skel->bss->inherit_cb_flags = 0;



	skel->data->test_kind = TCPOPT_EXP;

	skel->data->test_magic = 0xeB9F;

tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c

+2 −2
Original line number Diff line number Diff line
@@ -304,10 +304,10 @@ int misc_estab(struct bpf_sock_ops *skops) 
		passive_lport_n = __bpf_htons(passive_lport_h);

		bpf_setsockopt(skops, SOL_TCP, TCP_SAVE_SYN,

			       &true_val, sizeof(true_val));

		set_hdr_cb_flags(skops);

		set_hdr_cb_flags(skops, 0);

		break;

	case BPF_SOCK_OPS_TCP_CONNECT_CB:

		set_hdr_cb_flags(skops);

		set_hdr_cb_flags(skops, 0);

		break;

	case BPF_SOCK_OPS_PARSE_HDR_OPT_CB:

		return handle_parse_hdr(skops);

tools/testing/selftests/bpf/progs/test_tcp_hdr_options.c

+5 −2
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 


__u8 test_kind = TCPOPT_EXP;

__u16 test_magic = 0xeB9F;

__u32 inherit_cb_flags = 0;



struct bpf_test_option passive_synack_out = {};

struct bpf_test_option passive_fin_out	= {};
@@ -467,6 +468,8 @@ static int handle_passive_estab(struct bpf_sock_ops *skops) 
	struct tcphdr *th;

	int err;



	inherit_cb_flags = skops->bpf_sock_ops_cb_flags;



	err = load_option(skops, &passive_estab_in, true);

	if (err == -ENOENT) {

		/* saved_syn is not found. It was in syncookie mode.
@@ -600,10 +603,10 @@ int estab(struct bpf_sock_ops *skops) 
	case BPF_SOCK_OPS_TCP_LISTEN_CB:

		bpf_setsockopt(skops, SOL_TCP, TCP_SAVE_SYN,

			       &true_val, sizeof(true_val));

		set_hdr_cb_flags(skops);

		set_hdr_cb_flags(skops, BPF_SOCK_OPS_STATE_CB_FLAG);

		break;

	case BPF_SOCK_OPS_TCP_CONNECT_CB:

		set_hdr_cb_flags(skops);

		set_hdr_cb_flags(skops, 0);

		break;

	case BPF_SOCK_OPS_PARSE_HDR_OPT_CB:

		return handle_parse_hdr(skops);