Commit fa183a86 authored by Andrii Nakryiko's avatar Andrii Nakryiko
Browse files

Merge branch 'BPF iterator for UNIX domain socket.' 

Kuniyuki Iwashima says:

====================

This patch set adds BPF iterator support for UNIX domain socket.  The first
patch implements it, and the second adds "%c" support for BPF_SEQ_PRINTF().

Thanks to Yonghong Song for the fix [0] for the LLVM code gen.  The fix
prevents the LLVM compiler from transforming the loop exit condition '<' to
'!=', where the upper bound is not a constant.  The transformation leads
the verifier to interpret it as an infinite loop.

And thanks to Andrii Nakryiko for its workaround [1].

[0] https://reviews.llvm.org/D107483
[1] https://lore.kernel.org/netdev/CAEf4BzZ3sVx1m1mOCcPcuVPiY6cWEAO=6VGHDiXEs9ZVD-RoLg@mail.gmail.com/

Changelog:
  v6:
  - Align the header "Inde" column
  - Change int vars to __u64 not to break test_progs-no_alu32
  - Move the if statement into the for loop not to depend on the fix [0]
  - Drop the README change
  - Modify "%c" positive test patterns

  v5:
  https://lore.kernel.org/netdev/20210812164557.79046-1-kuniyu@amazon.co.jp/
  - Align header line of bpf_iter_unix.c
  - Add test for "%c"

  v4:
  https://lore.kernel.org/netdev/20210810092807.13190-1-kuniyu@amazon.co.jp/
  - Check IS_BUILTIN(CONFIG_UNIX)
  - Support "%c" in BPF_SEQ_PRINTF()
  - Uncomment the code to print the name of the abstract socket
  - Mention the LLVM fix in README.rst
  - Remove the 'aligned' attribute in bpf_iter.h
  - Keep the format string on a single line

  v3:
  https://lore.kernel.org/netdev/20210804070851.97834-1-kuniyu@amazon.co.jp/
  - Export some functions for CONFIG_UNIX=m

  v2:
  https://lore.kernel.org/netdev/20210803011110.21205-1-kuniyu@amazon.co.jp/
  - Implement bpf_iter specific seq_ops->stop()
  - Add bpf_iter__unix in bpf_iter.h
  - Move common definitions in selftest to bpf_tracing_net.h
  - Include the code for abstract UNIX domain socket as comment in selftest
  - Use ASSERT_OK_PTR() instead of CHECK()
  - Make ternary operators on single line

  v1:
  https://lore.kernel.org/netdev/20210729233645.4869-1-kuniyu@amazon.co.jp/


====================

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
parents d1bf7c4d ce547335

include/linux/btf_ids.h

+2 −1
Original line number Diff line number Diff line
@@ -172,7 +172,8 @@ extern struct btf_id_set name; 
	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, tcp_timewait_sock)		\

	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, tcp6_sock)			\

	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, udp_sock)			\

	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, udp6_sock)

	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, udp6_sock)			\

	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UNIX, unix_sock)



enum {

#define BTF_SOCK_TYPE(name, str) name,

kernel/bpf/helpers.c

+14 −0
Original line number Diff line number Diff line
@@ -907,6 +907,20 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args, 
			tmp_buf += err;

			num_spec++;



			continue;

		} else if (fmt[i] == 'c') {

			if (!tmp_buf)

				goto nocopy_fmt;



			if (tmp_buf_end == tmp_buf) {

				err = -ENOSPC;

				goto out;

			}



			*tmp_buf = raw_args[num_spec];

			tmp_buf++;

			num_spec++;



			continue;

		}

net/unix/af_unix.c

+93 −0
Original line number Diff line number Diff line
@@ -113,6 +113,7 @@ 
#include <linux/security.h>

#include <linux/freezer.h>

#include <linux/file.h>

#include <linux/btf_ids.h>



#include "scm.h"
@@ -3143,6 +3144,64 @@ static const struct seq_operations unix_seq_ops = { 
	.stop   = unix_seq_stop,

	.show   = unix_seq_show,

};



#if IS_BUILTIN(CONFIG_UNIX) && defined(CONFIG_BPF_SYSCALL)

struct bpf_iter__unix {

	__bpf_md_ptr(struct bpf_iter_meta *, meta);

	__bpf_md_ptr(struct unix_sock *, unix_sk);

	uid_t uid __aligned(8);

};



static int unix_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,

			      struct unix_sock *unix_sk, uid_t uid)

{

	struct bpf_iter__unix ctx;



	meta->seq_num--;  /* skip SEQ_START_TOKEN */

	ctx.meta = meta;

	ctx.unix_sk = unix_sk;

	ctx.uid = uid;

	return bpf_iter_run_prog(prog, &ctx);

}



static int bpf_iter_unix_seq_show(struct seq_file *seq, void *v)

{

	struct bpf_iter_meta meta;

	struct bpf_prog *prog;

	struct sock *sk = v;

	uid_t uid;



	if (v == SEQ_START_TOKEN)

		return 0;



	uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));

	meta.seq = seq;

	prog = bpf_iter_get_info(&meta, false);

	return unix_prog_seq_show(prog, &meta, v, uid);

}



static void bpf_iter_unix_seq_stop(struct seq_file *seq, void *v)

{

	struct bpf_iter_meta meta;

	struct bpf_prog *prog;



	if (!v) {

		meta.seq = seq;

		prog = bpf_iter_get_info(&meta, true);

		if (prog)

			(void)unix_prog_seq_show(prog, &meta, v, 0);

	}



	unix_seq_stop(seq, v);

}



static const struct seq_operations bpf_iter_unix_seq_ops = {

	.start	= unix_seq_start,

	.next	= unix_seq_next,

	.stop	= bpf_iter_unix_seq_stop,

	.show	= bpf_iter_unix_seq_show,

};

#endif

#endif



static const struct net_proto_family unix_family_ops = {
@@ -3183,6 +3242,35 @@ static struct pernet_operations unix_net_ops = { 
	.exit = unix_net_exit,

};



#if IS_BUILTIN(CONFIG_UNIX) && defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)

DEFINE_BPF_ITER_FUNC(unix, struct bpf_iter_meta *meta,

		     struct unix_sock *unix_sk, uid_t uid)



static const struct bpf_iter_seq_info unix_seq_info = {

	.seq_ops		= &bpf_iter_unix_seq_ops,

	.init_seq_private	= bpf_iter_init_seq_net,

	.fini_seq_private	= bpf_iter_fini_seq_net,

	.seq_priv_size		= sizeof(struct seq_net_private),

};



static struct bpf_iter_reg unix_reg_info = {

	.target			= "unix",

	.ctx_arg_info_size	= 1,

	.ctx_arg_info		= {

		{ offsetof(struct bpf_iter__unix, unix_sk),

		  PTR_TO_BTF_ID_OR_NULL },

	},

	.seq_info		= &unix_seq_info,

};



static void __init bpf_iter_register(void)

{

	unix_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UNIX];

	if (bpf_iter_reg_target(&unix_reg_info))

		pr_warn("Warning: could not register bpf iterator unix\n");

}

#endif



static int __init af_unix_init(void)

{

	int rc = -1;
@@ -3198,6 +3286,11 @@ static int __init af_unix_init(void) 
	sock_register(&unix_family_ops);

	register_pernet_subsys(&unix_net_ops);

	unix_bpf_build_proto();



#if IS_BUILTIN(CONFIG_UNIX) && defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)

	bpf_iter_register();

#endif



out:

	return rc;

}

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

+16 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include "bpf_iter_tcp6.skel.h"

#include "bpf_iter_udp4.skel.h"

#include "bpf_iter_udp6.skel.h"

#include "bpf_iter_unix.skel.h"

#include "bpf_iter_test_kern1.skel.h"

#include "bpf_iter_test_kern2.skel.h"

#include "bpf_iter_test_kern3.skel.h"
@@ -313,6 +314,19 @@ static void test_udp6(void) 
	bpf_iter_udp6__destroy(skel);

}



static void test_unix(void)

{

	struct bpf_iter_unix *skel;



	skel = bpf_iter_unix__open_and_load();

	if (!ASSERT_OK_PTR(skel, "bpf_iter_unix__open_and_load"))

		return;



	do_dummy_read(skel->progs.dump_unix);



	bpf_iter_unix__destroy(skel);

}



/* The expected string is less than 16 bytes */

static int do_read_with_fd(int iter_fd, const char *expected,

			   bool read_one_char)
@@ -1255,6 +1269,8 @@ void test_bpf_iter(void) 
		test_udp4();

	if (test__start_subtest("udp6"))

		test_udp6();

	if (test__start_subtest("unix"))

		test_unix();

	if (test__start_subtest("anon"))

		test_anon_iter(false);

	if (test__start_subtest("anon-read-one-char"))

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

+3 −1
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ 
#define EXP_ADDR_OUT "0000000000000000 ffff00000add4e55 "

#define EXP_ADDR_RET sizeof(EXP_ADDR_OUT "unknownhashedptr")



#define EXP_STR_OUT  "str1 longstr"

#define EXP_STR_OUT  "str1         a  b c      d e longstr"

#define EXP_STR_RET  sizeof(EXP_STR_OUT)



#define EXP_OVER_OUT "%over"
@@ -114,6 +114,8 @@ void test_snprintf_negative(void) 
	ASSERT_ERR(load_single_snprintf("%"), "invalid specifier 3");

	ASSERT_ERR(load_single_snprintf("%12345678"), "invalid specifier 4");

	ASSERT_ERR(load_single_snprintf("%--------"), "invalid specifier 5");

	ASSERT_ERR(load_single_snprintf("%lc"), "invalid specifier 6");

	ASSERT_ERR(load_single_snprintf("%llc"), "invalid specifier 7");

	ASSERT_ERR(load_single_snprintf("\x80"), "non ascii character");

	ASSERT_ERR(load_single_snprintf("\x1"), "non printable character");

}