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Commit d849f9f9 authored by Daniel Borkmann's avatar Daniel Borkmann
Browse files

Merge branch 'bpf-sk-msg-fields' 



John Fastabend says:

====================
In this series we add the ability for sk msg programs to read basic
sock information about the sock they are attached to. The second
patch adds the tests to the selftest test_verifier.

One observation that I had from writing this seriess is lots of the
./net/core/filter.c code is almost duplicated across program types.
I thought about building a template/macro that we could use as a
single block of code to read sock data out for multiple programs,
but I wasn't convinced it was worth it yet. The result was using a
macro saved a couple lines of code per block but made the code
a bit harder to read IMO. We can probably revisit the idea later
if we get more duplication.

v2: add errstr field to negative test_verifier test cases to ensure
    we get the expected err string back from the verifier.
====================

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parents 1cb61381 4da0dcab

include/linux/filter.h

+1 −0
Original line number Diff line number Diff line
@@ -517,6 +517,7 @@ struct sk_msg_buff { 
	bool sg_copy[MAX_SKB_FRAGS];

	__u32 flags;

	struct sock *sk_redir;

	struct sock *sk;

	struct sk_buff *skb;

	struct list_head list;

};

include/uapi/linux/bpf.h

+8 −0
Original line number Diff line number Diff line
@@ -2176,6 +2176,14 @@ enum sk_action { 
struct sk_msg_md {

	void *data;

	void *data_end;



	__u32 family;

	__u32 remote_ip4;	/* Stored in network byte order */

	__u32 local_ip4;	/* Stored in network byte order */

	__u32 remote_ip6[4];	/* Stored in network byte order */

	__u32 local_ip6[4];	/* Stored in network byte order */

	__u32 remote_port;	/* Stored in network byte order */

	__u32 local_port;	/* stored in host byte order */

};



#define BPF_TAG_SIZE	8

kernel/bpf/sockmap.c

+1 −0
Original line number Diff line number Diff line
@@ -523,6 +523,7 @@ static unsigned int smap_do_tx_msg(struct sock *sk, 
	}



	bpf_compute_data_pointers_sg(md);

	md->sk = sk;

	rc = (*prog->bpf_func)(md, prog->insnsi);

	psock->apply_bytes = md->apply_bytes;

net/core/filter.c

+111 −3
Original line number Diff line number Diff line
@@ -5148,18 +5148,23 @@ static bool sk_msg_is_valid_access(int off, int size, 
	switch (off) {

	case offsetof(struct sk_msg_md, data):

		info->reg_type = PTR_TO_PACKET;

		if (size != sizeof(__u64))

			return false;

		break;

	case offsetof(struct sk_msg_md, data_end):

		info->reg_type = PTR_TO_PACKET_END;

		if (size != sizeof(__u64))

			return false;

		break;

	default:

		if (size != sizeof(__u32))

			return false;

	}



	if (off < 0 || off >= sizeof(struct sk_msg_md))

		return false;

	if (off % size != 0)

		return false;

	if (size != sizeof(__u64))

		return false;



	return true;

}
@@ -5835,7 +5840,8 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type, 
		break;



	case offsetof(struct bpf_sock_ops, local_ip4):

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_rcv_saddr) != 4);

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common,

					  skc_rcv_saddr) != 4);



		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

					      struct bpf_sock_ops_kern, sk),
@@ -6152,6 +6158,7 @@ static u32 sk_msg_convert_ctx_access(enum bpf_access_type type, 
				     struct bpf_prog *prog, u32 *target_size)

{

	struct bpf_insn *insn = insn_buf;

	int off;



	switch (si->off) {

	case offsetof(struct sk_msg_md, data):
@@ -6164,6 +6171,107 @@ static u32 sk_msg_convert_ctx_access(enum bpf_access_type type, 
				      si->dst_reg, si->src_reg,

				      offsetof(struct sk_msg_buff, data_end));

		break;

	case offsetof(struct sk_msg_md, family):

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_family) != 2);



		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

					      struct sk_msg_buff, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct sk_msg_buff, sk));

		*insn++ = BPF_LDX_MEM(BPF_H, si->dst_reg, si->dst_reg,

				      offsetof(struct sock_common, skc_family));

		break;



	case offsetof(struct sk_msg_md, remote_ip4):

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_daddr) != 4);



		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

						struct sk_msg_buff, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct sk_msg_buff, sk));

		*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,

				      offsetof(struct sock_common, skc_daddr));

		break;



	case offsetof(struct sk_msg_md, local_ip4):

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common,

					  skc_rcv_saddr) != 4);



		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

					      struct sk_msg_buff, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct sk_msg_buff, sk));

		*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,

				      offsetof(struct sock_common,

					       skc_rcv_saddr));

		break;



	case offsetof(struct sk_msg_md, remote_ip6[0]) ...

	     offsetof(struct sk_msg_md, remote_ip6[3]):

#if IS_ENABLED(CONFIG_IPV6)

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common,

					  skc_v6_daddr.s6_addr32[0]) != 4);



		off = si->off;

		off -= offsetof(struct sk_msg_md, remote_ip6[0]);

		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

						struct sk_msg_buff, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct sk_msg_buff, sk));

		*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,

				      offsetof(struct sock_common,

					       skc_v6_daddr.s6_addr32[0]) +

				      off);

#else

		*insn++ = BPF_MOV32_IMM(si->dst_reg, 0);

#endif

		break;



	case offsetof(struct sk_msg_md, local_ip6[0]) ...

	     offsetof(struct sk_msg_md, local_ip6[3]):

#if IS_ENABLED(CONFIG_IPV6)

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common,

					  skc_v6_rcv_saddr.s6_addr32[0]) != 4);



		off = si->off;

		off -= offsetof(struct sk_msg_md, local_ip6[0]);

		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

						struct sk_msg_buff, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct sk_msg_buff, sk));

		*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,

				      offsetof(struct sock_common,

					       skc_v6_rcv_saddr.s6_addr32[0]) +

				      off);

#else

		*insn++ = BPF_MOV32_IMM(si->dst_reg, 0);

#endif

		break;



	case offsetof(struct sk_msg_md, remote_port):

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_dport) != 2);



		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

						struct sk_msg_buff, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct sk_msg_buff, sk));

		*insn++ = BPF_LDX_MEM(BPF_H, si->dst_reg, si->dst_reg,

				      offsetof(struct sock_common, skc_dport));

#ifndef __BIG_ENDIAN_BITFIELD

		*insn++ = BPF_ALU32_IMM(BPF_LSH, si->dst_reg, 16);

#endif

		break;



	case offsetof(struct sk_msg_md, local_port):

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_num) != 2);



		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

						struct sk_msg_buff, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct sk_msg_buff, sk));

		*insn++ = BPF_LDX_MEM(BPF_H, si->dst_reg, si->dst_reg,

				      offsetof(struct sock_common, skc_num));

		break;

	}



	return insn - insn_buf;

tools/include/uapi/linux/bpf.h

+8 −0
Original line number Diff line number Diff line
@@ -2176,6 +2176,14 @@ enum sk_action { 
struct sk_msg_md {

	void *data;

	void *data_end;



	__u32 family;

	__u32 remote_ip4;	/* Stored in network byte order */

	__u32 local_ip4;	/* Stored in network byte order */

	__u32 remote_ip6[4];	/* Stored in network byte order */

	__u32 local_ip6[4];	/* Stored in network byte order */

	__u32 remote_port;	/* Stored in network byte order */

	__u32 local_port;	/* stored in host byte order */

};



#define BPF_TAG_SIZE	8