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selftests/bpf: Selftest for sys_bind hooks 

Add selftest to work with bpf_sock_addr context from
`BPF_PROG_TYPE_CGROUP_SOCK_ADDR` programs.

Try to bind(2) on IP:port and apply:
* loads to make sure context can be read correctly, including narrow
  loads (byte, half) for IP and full-size loads (word) for all fields;
* stores to those fields allowed by verifier.

All combination from IPv4/IPv6 and TCP/UDP are tested.

Both scenarios are tested:
* valid programs can be loaded and attached;
* invalid programs can be neither loaded nor attached.

Test passes when expected data can be read from context in the
BPF-program, and after the call to bind(2) socket is bound to IP:port
pair that was written by BPF-program to the context.

Example:
  # ./test_sock_addr
  Attached bind4 program.
  Test case #1 (IPv4/TCP):
          Requested: bind(192.168.1.254, 4040) ..
             Actual: bind(127.0.0.1, 4444)
  Test case #2 (IPv4/UDP):
          Requested: bind(192.168.1.254, 4040) ..
             Actual: bind(127.0.0.1, 4444)
  Attached bind6 program.
  Test case #3 (IPv6/TCP):
          Requested: bind(face:b00c:1234:5678::abcd, 6060) ..
             Actual: bind(::1, 6666)
  Test case #4 (IPv6/UDP):
          Requested: bind(face:b00c:1234:5678::abcd, 6060) ..
             Actual: bind(::1, 6666)
  ### SUCCESS

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Andrey Ignatov 2018-03-30 15:08:03 -07:00 committed by Daniel Borkmann
parent 4fbac77d2d
commit e50b0a6f08
4 changed files with 517 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
tools/include/uapi/linux/bpf.h
View File

@ -136,6 +136,7 @@ enum bpf_prog_type {
BPF_PROG_TYPE_CGROUP_DEVICE,
BPF_PROG_TYPE_SK_MSG,
BPF_PROG_TYPE_RAW_TRACEPOINT,
BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
};
enum bpf_attach_type {
@ -147,6 +148,8 @@ enum bpf_attach_type {
BPF_SK_SKB_STREAM_VERDICT,
BPF_CGROUP_DEVICE,
BPF_SK_MSG_VERDICT,
BPF_CGROUP_INET4_BIND,
BPF_CGROUP_INET6_BIND,
__MAX_BPF_ATTACH_TYPE
};
@ -1009,6 +1012,26 @@ struct bpf_map_info {
__u64 netns_ino;
} __attribute__((aligned(8)));
/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
* by user and intended to be used by socket (e.g. to bind to, depends on
* attach attach type).
*/
struct bpf_sock_addr {
__u32 user_family; /* Allows 4-byte read, but no write. */
__u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
* Stored in network byte order.
*/
__u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
* Stored in network byte order.
*/
__u32 user_port; /* Allows 4-byte read and write.
* Stored in network byte order
*/
__u32 family; /* Allows 4-byte read, but no write */
__u32 type; /* Allows 4-byte read, but no write */
__u32 protocol; /* Allows 4-byte read, but no write */
};
/* User bpf_sock_ops struct to access socket values and specify request ops
* and their replies.
* Some of this fields are in network (bigendian) byte order and may need

6
tools/lib/bpf/libbpf.c
View File

@ -1859,6 +1859,9 @@ static void bpf_program__set_expected_attach_type(struct bpf_program *prog,
#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_FULL(string, ptype, 0)
#define BPF_SA_PROG_SEC(string, ptype) \
BPF_PROG_SEC_FULL(string, BPF_PROG_TYPE_CGROUP_SOCK_ADDR, ptype)
static const struct {
const char *sec;
size_t len;
@ -1882,10 +1885,13 @@ static const struct {
BPF_PROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS),
BPF_PROG_SEC("sk_skb", BPF_PROG_TYPE_SK_SKB),
BPF_PROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG),
BPF_SA_PROG_SEC("cgroup/bind4", BPF_CGROUP_INET4_BIND),
BPF_SA_PROG_SEC("cgroup/bind6", BPF_CGROUP_INET6_BIND),
};
#undef BPF_PROG_SEC
#undef BPF_PROG_SEC_FULL
#undef BPF_SA_PROG_SEC
static int bpf_program__identify_section(struct bpf_program *prog)
{

3
tools/testing/selftests/bpf/Makefile
View File

@ -23,7 +23,7 @@ urandom_read: urandom_read.c
# Order correspond to 'make run_tests' order
TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
test_align test_verifier_log test_dev_cgroup test_tcpbpf_user
test_align test_verifier_log test_dev_cgroup test_tcpbpf_user test_sock_addr
TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \
@ -51,6 +51,7 @@ $(TEST_GEN_PROGS): $(BPFOBJ)
$(TEST_GEN_PROGS_EXTENDED): $(OUTPUT)/libbpf.a
$(OUTPUT)/test_dev_cgroup: cgroup_helpers.c
$(OUTPUT)/test_sock_addr: cgroup_helpers.c
.PHONY: force

486
tools/testing/selftests/bpf/test_sock_addr.c Normal file
View File

@ -0,0 +1,486 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <linux/filter.h>
#include <bpf/bpf.h>
#include "cgroup_helpers.h"
#define CG_PATH "/foo"
#define SERV4_IP "192.168.1.254"
#define SERV4_REWRITE_IP "127.0.0.1"
#define SERV4_PORT 4040
#define SERV4_REWRITE_PORT 4444
#define SERV6_IP "face:b00c:1234:5678::abcd"
#define SERV6_REWRITE_IP "::1"
#define SERV6_PORT 6060
#define SERV6_REWRITE_PORT 6666
#define INET_NTOP_BUF 40
typedef int (*load_fn)(enum bpf_attach_type, const char *comment);
typedef int (*info_fn)(int, struct sockaddr *, socklen_t *);
struct program {
enum bpf_attach_type type;
load_fn loadfn;
int fd;
const char *name;
enum bpf_attach_type invalid_type;
};
char bpf_log_buf[BPF_LOG_BUF_SIZE];
static int mk_sockaddr(int domain, const char *ip, unsigned short port,
struct sockaddr *addr, socklen_t addr_len)
{
struct sockaddr_in6 *addr6;
struct sockaddr_in *addr4;
if (domain != AF_INET && domain != AF_INET6) {
log_err("Unsupported address family");
return -1;
}
memset(addr, 0, addr_len);
if (domain == AF_INET) {
if (addr_len < sizeof(struct sockaddr_in))
return -1;
addr4 = (struct sockaddr_in *)addr;
addr4->sin_family = domain;
addr4->sin_port = htons(port);
if (inet_pton(domain, ip, (void *)&addr4->sin_addr) != 1) {
log_err("Invalid IPv4: %s", ip);
return -1;
}
} else if (domain == AF_INET6) {
if (addr_len < sizeof(struct sockaddr_in6))
return -1;
addr6 = (struct sockaddr_in6 *)addr;
addr6->sin6_family = domain;
addr6->sin6_port = htons(port);
if (inet_pton(domain, ip, (void *)&addr6->sin6_addr) != 1) {
log_err("Invalid IPv6: %s", ip);
return -1;
}
}
return 0;
}
static int load_insns(enum bpf_attach_type attach_type,
const struct bpf_insn *insns, size_t insns_cnt,
const char *comment)
{
struct bpf_load_program_attr load_attr;
int ret;
memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
load_attr.prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
load_attr.expected_attach_type = attach_type;
load_attr.insns = insns;
load_attr.insns_cnt = insns_cnt;
load_attr.license = "GPL";
ret = bpf_load_program_xattr(&load_attr, bpf_log_buf, BPF_LOG_BUF_SIZE);
if (ret < 0 && comment) {
log_err(">>> Loading %s program error.\n"
">>> Output from verifier:\n%s\n-------\n",
comment, bpf_log_buf);
}
return ret;
}
/* [1] These testing programs try to read different context fields, including
* narrow loads of different sizes from user_ip4 and user_ip6, and write to
* those allowed to be overridden.
*
* [2] BPF_LD_IMM64 & BPF_JMP_REG are used below whenever there is a need to
* compare a register with unsigned 32bit integer. BPF_JMP_IMM can't be used
* in such cases since it accepts only _signed_ 32bit integer as IMM
* argument. Also note that BPF_LD_IMM64 contains 2 instructions what matters
* to count jumps properly.
*/
static int bind4_prog_load(enum bpf_attach_type attach_type,
const char *comment)
{
union {
uint8_t u4_addr8[4];
uint16_t u4_addr16[2];
uint32_t u4_addr32;
} ip4;
struct sockaddr_in addr4_rw;
if (inet_pton(AF_INET, SERV4_IP, (void *)&ip4) != 1) {
log_err("Invalid IPv4: %s", SERV4_IP);
return -1;
}
if (mk_sockaddr(AF_INET, SERV4_REWRITE_IP, SERV4_REWRITE_PORT,
(struct sockaddr *)&addr4_rw, sizeof(addr4_rw)) == -1)
return -1;
/* See [1]. */
struct bpf_insn insns[] = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
/* if (sk.family == AF_INET && */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, family)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET, 16),
/* (sk.type == SOCK_DGRAM || sk.type == SOCK_STREAM) && */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, type)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, SOCK_DGRAM, 1),
BPF_JMP_A(1),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, SOCK_STREAM, 12),
/* 1st_byte_of_user_ip4 == expected && */
BPF_LDX_MEM(BPF_B, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, user_ip4)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr8[0], 10),
/* 1st_half_of_user_ip4 == expected && */
BPF_LDX_MEM(BPF_H, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, user_ip4)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr16[0], 8),
/* whole_user_ip4 == expected) { */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, user_ip4)),
BPF_LD_IMM64(BPF_REG_8, ip4.u4_addr32), /* See [2]. */
BPF_JMP_REG(BPF_JNE, BPF_REG_7, BPF_REG_8, 4),
/* user_ip4 = addr4_rw.sin_addr */
BPF_MOV32_IMM(BPF_REG_7, addr4_rw.sin_addr.s_addr),
BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
offsetof(struct bpf_sock_addr, user_ip4)),
/* user_port = addr4_rw.sin_port */
BPF_MOV32_IMM(BPF_REG_7, addr4_rw.sin_port),
BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
offsetof(struct bpf_sock_addr, user_port)),
/* } */
/* return 1 */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
};
return load_insns(attach_type, insns,
sizeof(insns) / sizeof(struct bpf_insn), comment);
}
static int bind6_prog_load(enum bpf_attach_type attach_type,
const char *comment)
{
struct sockaddr_in6 addr6_rw;
struct in6_addr ip6;
if (inet_pton(AF_INET6, SERV6_IP, (void *)&ip6) != 1) {
log_err("Invalid IPv6: %s", SERV6_IP);
return -1;
}
if (mk_sockaddr(AF_INET6, SERV6_REWRITE_IP, SERV6_REWRITE_PORT,
(struct sockaddr *)&addr6_rw, sizeof(addr6_rw)) == -1)
return -1;
/* See [1]. */
struct bpf_insn insns[] = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
/* if (sk.family == AF_INET6 && */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, family)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET6, 18),
/* 5th_byte_of_user_ip6 == expected && */
BPF_LDX_MEM(BPF_B, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, user_ip6[1])),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip6.s6_addr[4], 16),
/* 3rd_half_of_user_ip6 == expected && */
BPF_LDX_MEM(BPF_H, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, user_ip6[1])),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip6.s6_addr16[2], 14),
/* last_word_of_user_ip6 == expected) { */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, user_ip6[3])),
BPF_LD_IMM64(BPF_REG_8, ip6.s6_addr32[3]), /* See [2]. */
BPF_JMP_REG(BPF_JNE, BPF_REG_7, BPF_REG_8, 10),
#define STORE_IPV6_WORD(N) \
BPF_MOV32_IMM(BPF_REG_7, addr6_rw.sin6_addr.s6_addr32[N]), \
BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7, \
offsetof(struct bpf_sock_addr, user_ip6[N]))
/* user_ip6 = addr6_rw.sin6_addr */
STORE_IPV6_WORD(0),
STORE_IPV6_WORD(1),
STORE_IPV6_WORD(2),
STORE_IPV6_WORD(3),
/* user_port = addr6_rw.sin6_port */
BPF_MOV32_IMM(BPF_REG_7, addr6_rw.sin6_port),
BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
offsetof(struct bpf_sock_addr, user_port)),
/* } */
/* return 1 */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
};
return load_insns(attach_type, insns,
sizeof(insns) / sizeof(struct bpf_insn), comment);
}
static void print_ip_port(int sockfd, info_fn fn, const char *fmt)
{
char addr_buf[INET_NTOP_BUF];
struct sockaddr_storage addr;
struct sockaddr_in6 *addr6;
struct sockaddr_in *addr4;
socklen_t addr_len;
unsigned short port;
void *nip;
addr_len = sizeof(struct sockaddr_storage);
memset(&addr, 0, addr_len);
if (fn(sockfd, (struct sockaddr *)&addr, (socklen_t *)&addr_len) == 0) {
if (addr.ss_family == AF_INET) {
addr4 = (struct sockaddr_in *)&addr;
nip = (void *)&addr4->sin_addr;
port = ntohs(addr4->sin_port);
} else if (addr.ss_family == AF_INET6) {
addr6 = (struct sockaddr_in6 *)&addr;
nip = (void *)&addr6->sin6_addr;
port = ntohs(addr6->sin6_port);
} else {
return;
}
const char *addr_str =
inet_ntop(addr.ss_family, nip, addr_buf, INET_NTOP_BUF);
printf(fmt, addr_str ? addr_str : "??", port);
}
}
static void print_local_ip_port(int sockfd, const char *fmt)
{
print_ip_port(sockfd, getsockname, fmt);
}
static int start_server(int type, const struct sockaddr_storage *addr,
socklen_t addr_len)
{
int fd;
fd = socket(addr->ss_family, type, 0);
if (fd == -1) {
log_err("Failed to create server socket");
goto out;
}
if (bind(fd, (const struct sockaddr *)addr, addr_len) == -1) {
log_err("Failed to bind server socket");
goto close_out;
}
if (type == SOCK_STREAM) {
if (listen(fd, 128) == -1) {
log_err("Failed to listen on server socket");
goto close_out;
}
}
print_local_ip_port(fd, "\t Actual: bind(%s, %d)\n");
goto out;
close_out:
close(fd);
fd = -1;
out:
return fd;
}
static void print_test_case_num(int domain, int type)
{
static int test_num;
printf("Test case #%d (%s/%s):\n", ++test_num,
(domain == AF_INET ? "IPv4" :
domain == AF_INET6 ? "IPv6" :
"unknown_domain"),
(type == SOCK_STREAM ? "TCP" :
type == SOCK_DGRAM ? "UDP" :
"unknown_type"));
}
static int run_test_case(int domain, int type, const char *ip,
unsigned short port)
{
struct sockaddr_storage addr;
socklen_t addr_len = sizeof(addr);
int servfd = -1;
int err = 0;
print_test_case_num(domain, type);
if (mk_sockaddr(domain, ip, port, (struct sockaddr *)&addr,
addr_len) == -1)
return -1;
printf("\tRequested: bind(%s, %d) ..\n", ip, port);
servfd = start_server(type, &addr, addr_len);
if (servfd == -1)
goto err;
goto out;
err:
err = -1;
out:
close(servfd);
return err;
}
static void close_progs_fds(struct program *progs, size_t prog_cnt)
{
size_t i;
for (i = 0; i < prog_cnt; ++i) {
close(progs[i].fd);
progs[i].fd = -1;
}
}
static int load_and_attach_progs(int cgfd, struct program *progs,
size_t prog_cnt)
{
size_t i;
for (i = 0; i < prog_cnt; ++i) {
progs[i].fd = progs[i].loadfn(progs[i].invalid_type, NULL);
if (progs[i].fd != -1) {
log_err("Load with invalid type accepted for %s",
progs[i].name);
goto err;
}
progs[i].fd = progs[i].loadfn(progs[i].type, progs[i].name);
if (progs[i].fd == -1) {
log_err("Failed to load program %s", progs[i].name);
goto err;
}
if (bpf_prog_attach(progs[i].fd, cgfd, progs[i].invalid_type,
BPF_F_ALLOW_OVERRIDE) != -1) {
log_err("Attach with invalid type accepted for %s",
progs[i].name);
goto err;
}
if (bpf_prog_attach(progs[i].fd, cgfd, progs[i].type,
BPF_F_ALLOW_OVERRIDE) == -1) {
log_err("Failed to attach program %s", progs[i].name);
goto err;
}
printf("Attached %s program.\n", progs[i].name);
}
return 0;
err:
close_progs_fds(progs, prog_cnt);
return -1;
}
static int run_domain_test(int domain, int cgfd, struct program *progs,
size_t prog_cnt, const char *ip, unsigned short port)
{
int err = 0;
if (load_and_attach_progs(cgfd, progs, prog_cnt) == -1)
goto err;
if (run_test_case(domain, SOCK_STREAM, ip, port) == -1)
goto err;
if (run_test_case(domain, SOCK_DGRAM, ip, port) == -1)
goto err;
goto out;
err:
err = -1;
out:
close_progs_fds(progs, prog_cnt);
return err;
}
static int run_test(void)
{
size_t inet6_prog_cnt;
size_t inet_prog_cnt;
int cgfd = -1;
int err = 0;
struct program inet6_progs[] = {
{BPF_CGROUP_INET6_BIND, bind6_prog_load, -1, "bind6",
BPF_CGROUP_INET4_BIND},
};
inet6_prog_cnt = sizeof(inet6_progs) / sizeof(struct program);
struct program inet_progs[] = {
{BPF_CGROUP_INET4_BIND, bind4_prog_load, -1, "bind4",
BPF_CGROUP_INET6_BIND},
};
inet_prog_cnt = sizeof(inet_progs) / sizeof(struct program);
if (setup_cgroup_environment())
goto err;
cgfd = create_and_get_cgroup(CG_PATH);
if (!cgfd)
goto err;
if (join_cgroup(CG_PATH))
goto err;
if (run_domain_test(AF_INET, cgfd, inet_progs, inet_prog_cnt, SERV4_IP,
SERV4_PORT) == -1)
goto err;
if (run_domain_test(AF_INET6, cgfd, inet6_progs, inet6_prog_cnt,
SERV6_IP, SERV6_PORT) == -1)
goto err;
goto out;
err:
err = -1;
out:
close(cgfd);
cleanup_cgroup_environment();
printf(err ? "### FAIL\n" : "### SUCCESS\n");
return err;
}
int main(int argc, char **argv)
{
return run_test();
}