From: Menglong Dong imagedong@tencent.com
With previous patch, kernel is able to 'put_port' after sys_bind() fails. Add the test for that case: rebind another port after sys_bind() fails. If the bind success, it means previous bind operation is already undoed.
Signed-off-by: Menglong Dong imagedong@tencent.com --- tools/testing/selftests/bpf/test_sock.c | 150 ++++++++++++++++++++---- 1 file changed, 130 insertions(+), 20 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_sock.c b/tools/testing/selftests/bpf/test_sock.c index 94f9b126f5ed..fe10f8134278 100644 --- a/tools/testing/selftests/bpf/test_sock.c +++ b/tools/testing/selftests/bpf/test_sock.c @@ -35,12 +35,15 @@ struct sock_test { /* Endpoint to bind() to */ const char *ip; unsigned short port; + unsigned short port_retry; /* Expected test result */ enum { LOAD_REJECT, ATTACH_REJECT, BIND_REJECT, SUCCESS, + RETRY_SUCCESS, + RETRY_REJECT } result; };
@@ -251,6 +254,99 @@ static struct sock_test tests[] = { .port = 4098, .result = SUCCESS, }, + { + .descr = "bind4 deny specific IP & port of TCP, and retry", + .insns = { + BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), + + /* if (ip == expected && port == expected) */ + BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6, + offsetof(struct bpf_sock, src_ip4)), + BPF_JMP_IMM(BPF_JNE, BPF_REG_7, + __bpf_constant_ntohl(0x7F000001), 4), + BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6, + offsetof(struct bpf_sock, src_port)), + BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2), + + /* return DENY; */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_JMP_A(1), + + /* else return ALLOW; */ + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_EXIT_INSN(), + }, + .expected_attach_type = BPF_CGROUP_INET4_POST_BIND, + .attach_type = BPF_CGROUP_INET4_POST_BIND, + .domain = AF_INET, + .type = SOCK_STREAM, + .ip = "127.0.0.1", + .port = 4098, + .port_retry = 5000, + .result = RETRY_SUCCESS, + }, + { + .descr = "bind4 deny specific IP & port of UDP, and retry", + .insns = { + BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), + + /* if (ip == expected && port == expected) */ + BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6, + offsetof(struct bpf_sock, src_ip4)), + BPF_JMP_IMM(BPF_JNE, BPF_REG_7, + __bpf_constant_ntohl(0x7F000001), 4), + BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6, + offsetof(struct bpf_sock, src_port)), + BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2), + + /* return DENY; */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_JMP_A(1), + + /* else return ALLOW; */ + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_EXIT_INSN(), + }, + .expected_attach_type = BPF_CGROUP_INET4_POST_BIND, + .attach_type = BPF_CGROUP_INET4_POST_BIND, + .domain = AF_INET, + .type = SOCK_DGRAM, + .ip = "127.0.0.1", + .port = 4098, + .port_retry = 5000, + .result = RETRY_SUCCESS, + }, + { + .descr = "bind6 deny specific IP & port, and retry", + .insns = { + BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), + + /* if (ip == expected && port == expected) */ + BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6, + offsetof(struct bpf_sock, src_ip6[3])), + BPF_JMP_IMM(BPF_JNE, BPF_REG_7, + __bpf_constant_ntohl(0x00000001), 4), + BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6, + offsetof(struct bpf_sock, src_port)), + BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x2001, 2), + + /* return DENY; */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_JMP_A(1), + + /* else return ALLOW; */ + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_EXIT_INSN(), + }, + .expected_attach_type = BPF_CGROUP_INET6_POST_BIND, + .attach_type = BPF_CGROUP_INET6_POST_BIND, + .domain = AF_INET6, + .type = SOCK_STREAM, + .ip = "::1", + .port = 8193, + .port_retry = 9000, + .result = RETRY_SUCCESS, + }, { .descr = "bind4 allow all", .insns = { @@ -315,14 +411,15 @@ static int attach_sock_prog(int cgfd, int progfd, return bpf_prog_attach(progfd, cgfd, attach_type, BPF_F_ALLOW_OVERRIDE); }
-static int bind_sock(int domain, int type, const char *ip, unsigned short port) +static int bind_sock(int domain, int type, const char *ip, + unsigned short port, unsigned short port_retry) { struct sockaddr_storage addr; struct sockaddr_in6 *addr6; struct sockaddr_in *addr4; int sockfd = -1; socklen_t len; - int err = 0; + int res = SUCCESS;
sockfd = socket(domain, type, 0); if (sockfd < 0) @@ -348,21 +445,44 @@ static int bind_sock(int domain, int type, const char *ip, unsigned short port) goto err; }
- if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1) - goto err; + if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1) { + /* sys_bind() may fail for different reasons, errno has to be + * checked to confirm that BPF program rejected it. + */ + if (errno != EPERM) + goto err; + if (port_retry) + goto retry; + res = BIND_REJECT; + goto out; + }
+ goto out; +retry: + if (domain == AF_INET) + addr4->sin_port = htons(port_retry); + else + addr6->sin6_port = htons(port_retry); + if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1) { + if (errno != EPERM) + goto err; + res = RETRY_REJECT; + } else { + res = RETRY_SUCCESS; + } goto out; err: - err = -1; + res = -1; out: close(sockfd); - return err; + return res; }
static int run_test_case(int cgfd, const struct sock_test *test) { int progfd = -1; int err = 0; + int res;
printf("Test case: %s .. ", test->descr); progfd = load_sock_prog(test->insns, test->expected_attach_type); @@ -380,21 +500,11 @@ static int run_test_case(int cgfd, const struct sock_test *test) goto err; }
- if (bind_sock(test->domain, test->type, test->ip, test->port) == -1) { - /* sys_bind() may fail for different reasons, errno has to be - * checked to confirm that BPF program rejected it. - */ - if (test->result == BIND_REJECT && errno == EPERM) - goto out; - else - goto err; - } - + res = bind_sock(test->domain, test->type, test->ip, test->port, + test->port_retry); + if (res > 0 && test->result == res) + goto out;
- if (test->result != SUCCESS) - goto err; - - goto out; err: err = -1; out: