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[88.74.206.207]) by smtp.gmail.com with ESMTPSA id p16-20020a1709060dd000b0094f698073e0sm3044509eji.123.2023.05.22.06.24.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 May 2023 06:24:57 -0700 (PDT) From: Alexander Mikhalitsyn To: davem@davemloft.net Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Alexander Mikhalitsyn , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Leon Romanovsky , David Ahern , Arnd Bergmann , Kees Cook , Christian Brauner , Kuniyuki Iwashima , linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH net-next v6 3/3] selftests: net: add SCM_PIDFD / SO_PEERPIDFD test Date: Mon, 22 May 2023 15:24:39 +0200 Message-Id: <20230522132439.634031-4-aleksandr.mikhalitsyn@canonical.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230522132439.634031-1-aleksandr.mikhalitsyn@canonical.com> References: <20230522132439.634031-1-aleksandr.mikhalitsyn@canonical.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Basic test to check consistency between: - SCM_CREDENTIALS and SCM_PIDFD - SO_PEERCRED and SO_PEERPIDFD Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Leon Romanovsky Cc: David Ahern Cc: Arnd Bergmann Cc: Kees Cook Cc: Christian Brauner Cc: Kuniyuki Iwashima Cc: linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Signed-off-by: Alexander Mikhalitsyn --- v3: - started using kselftest lib (thanks to Kuniyuki Iwashima for suggestion/= review) - now test covers abstract sockets too and SOCK_DGRAM sockets --- tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/af_unix/Makefile | 3 +- .../testing/selftests/net/af_unix/scm_pidfd.c | 430 ++++++++++++++++++ 3 files changed, 433 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/net/af_unix/scm_pidfd.c diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftes= ts/net/.gitignore index 80f06aa62034..83fd1ebd34ec 100644 --- a/tools/testing/selftests/net/.gitignore +++ b/tools/testing/selftests/net/.gitignore @@ -26,6 +26,7 @@ reuseport_bpf_cpu reuseport_bpf_numa reuseport_dualstack rxtimestamp +scm_pidfd sk_bind_sendto_listen sk_connect_zero_addr socket diff --git a/tools/testing/selftests/net/af_unix/Makefile b/tools/testing/s= elftests/net/af_unix/Makefile index 1e4b397cece6..221c387a7d7f 100644 --- a/tools/testing/selftests/net/af_unix/Makefile +++ b/tools/testing/selftests/net/af_unix/Makefile @@ -1,3 +1,4 @@ -TEST_GEN_PROGS :=3D diag_uid test_unix_oob unix_connect +CFLAGS +=3D $(KHDR_INCLUDES) +TEST_GEN_PROGS :=3D diag_uid test_unix_oob unix_connect scm_pidfd =20 include ../../lib.mk diff --git a/tools/testing/selftests/net/af_unix/scm_pidfd.c b/tools/testin= g/selftests/net/af_unix/scm_pidfd.c new file mode 100644 index 000000000000..a86222143d79 --- /dev/null +++ b/tools/testing/selftests/net/af_unix/scm_pidfd.c @@ -0,0 +1,430 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../../kselftest_harness.h" + +#define clean_errno() (errno =3D=3D 0 ? "None" : strerror(errno)) +#define log_err(MSG, ...) = \ + fprintf(stderr, "(%s:%d: errno: %s) " MSG "\n", __FILE__, __LINE__, \ + clean_errno(), ##__VA_ARGS__) + +#ifndef SCM_PIDFD +#define SCM_PIDFD 0x04 +#endif + +static void child_die() +{ + exit(1); +} + +static int safe_int(const char *numstr, int *converted) +{ + char *err =3D NULL; + long sli; + + errno =3D 0; + sli =3D strtol(numstr, &err, 0); + if (errno =3D=3D ERANGE && (sli =3D=3D LONG_MAX || sli =3D=3D LONG_MIN)) + return -ERANGE; + + if (errno !=3D 0 && sli =3D=3D 0) + return -EINVAL; + + if (err =3D=3D numstr || *err !=3D '\0') + return -EINVAL; + + if (sli > INT_MAX || sli < INT_MIN) + return -ERANGE; + + *converted =3D (int)sli; + return 0; +} + +static int char_left_gc(const char *buffer, size_t len) +{ + size_t i; + + for (i =3D 0; i < len; i++) { + if (buffer[i] =3D=3D ' ' || buffer[i] =3D=3D '\t') + continue; + + return i; + } + + return 0; +} + +static int char_right_gc(const char *buffer, size_t len) +{ + int i; + + for (i =3D len - 1; i >=3D 0; i--) { + if (buffer[i] =3D=3D ' ' || buffer[i] =3D=3D '\t' || + buffer[i] =3D=3D '\n' || buffer[i] =3D=3D '\0') + continue; + + return i + 1; + } + + return 0; +} + +static char *trim_whitespace_in_place(char *buffer) +{ + buffer +=3D char_left_gc(buffer, strlen(buffer)); + buffer[char_right_gc(buffer, strlen(buffer))] =3D '\0'; + return buffer; +} + +/* borrowed (with all helpers) from pidfd/pidfd_open_test.c */ +static pid_t get_pid_from_fdinfo_file(int pidfd, const char *key, size_t k= eylen) +{ + int ret; + char path[512]; + FILE *f; + size_t n =3D 0; + pid_t result =3D -1; + char *line =3D NULL; + + snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd); + + f =3D fopen(path, "re"); + if (!f) + return -1; + + while (getline(&line, &n, f) !=3D -1) { + char *numstr; + + if (strncmp(line, key, keylen)) + continue; + + numstr =3D trim_whitespace_in_place(line + 4); + ret =3D safe_int(numstr, &result); + if (ret < 0) + goto out; + + break; + } + +out: + free(line); + fclose(f); + return result; +} + +static int cmsg_check(int fd) +{ + struct msghdr msg =3D { 0 }; + struct cmsghdr *cmsg; + struct iovec iov; + struct ucred *ucred =3D NULL; + int data =3D 0; + char control[CMSG_SPACE(sizeof(struct ucred)) + + CMSG_SPACE(sizeof(int))] =3D { 0 }; + int *pidfd =3D NULL; + pid_t parent_pid; + int err; + + iov.iov_base =3D &data; + iov.iov_len =3D sizeof(data); + + msg.msg_iov =3D &iov; + msg.msg_iovlen =3D 1; + msg.msg_control =3D control; + msg.msg_controllen =3D sizeof(control); + + err =3D recvmsg(fd, &msg, 0); + if (err < 0) { + log_err("recvmsg"); + return 1; + } + + if (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC)) { + log_err("recvmsg: truncated"); + return 1; + } + + for (cmsg =3D CMSG_FIRSTHDR(&msg); cmsg !=3D NULL; + cmsg =3D CMSG_NXTHDR(&msg, cmsg)) { + if (cmsg->cmsg_level =3D=3D SOL_SOCKET && + cmsg->cmsg_type =3D=3D SCM_PIDFD) { + if (cmsg->cmsg_len < sizeof(*pidfd)) { + log_err("CMSG parse: SCM_PIDFD wrong len"); + return 1; + } + + pidfd =3D (void *)CMSG_DATA(cmsg); + } + + if (cmsg->cmsg_level =3D=3D SOL_SOCKET && + cmsg->cmsg_type =3D=3D SCM_CREDENTIALS) { + if (cmsg->cmsg_len < sizeof(*ucred)) { + log_err("CMSG parse: SCM_CREDENTIALS wrong len"); + return 1; + } + + ucred =3D (void *)CMSG_DATA(cmsg); + } + } + + /* send(pfd, "x", sizeof(char), 0) */ + if (data !=3D 'x') { + log_err("recvmsg: data corruption"); + return 1; + } + + if (!pidfd) { + log_err("CMSG parse: SCM_PIDFD not found"); + return 1; + } + + if (!ucred) { + log_err("CMSG parse: SCM_CREDENTIALS not found"); + return 1; + } + + /* pidfd from SCM_PIDFD should point to the parent process PID */ + parent_pid =3D + get_pid_from_fdinfo_file(*pidfd, "Pid:", sizeof("Pid:") - 1); + if (parent_pid !=3D getppid()) { + log_err("wrong SCM_PIDFD %d !=3D %d", parent_pid, getppid()); + return 1; + } + + return 0; +} + +struct sock_addr { + char sock_name[32]; + struct sockaddr_un listen_addr; + socklen_t addrlen; +}; + +FIXTURE(scm_pidfd) +{ + int server; + pid_t client_pid; + int startup_pipe[2]; + struct sock_addr server_addr; + struct sock_addr *client_addr; +}; + +FIXTURE_VARIANT(scm_pidfd) +{ + int type; + bool abstract; +}; + +FIXTURE_VARIANT_ADD(scm_pidfd, stream_pathname) +{ + .type =3D SOCK_STREAM, + .abstract =3D 0, +}; + +FIXTURE_VARIANT_ADD(scm_pidfd, stream_abstract) +{ + .type =3D SOCK_STREAM, + .abstract =3D 1, +}; + +FIXTURE_VARIANT_ADD(scm_pidfd, dgram_pathname) +{ + .type =3D SOCK_DGRAM, + .abstract =3D 0, +}; + +FIXTURE_VARIANT_ADD(scm_pidfd, dgram_abstract) +{ + .type =3D SOCK_DGRAM, + .abstract =3D 1, +}; + +FIXTURE_SETUP(scm_pidfd) +{ + self->client_addr =3D mmap(NULL, sizeof(*self->client_addr), PROT_READ | = PROT_WRITE, + MAP_SHARED | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(MAP_FAILED, self->client_addr); +} + +FIXTURE_TEARDOWN(scm_pidfd) +{ + close(self->server); + + kill(self->client_pid, SIGKILL); + waitpid(self->client_pid, NULL, 0); + + if (!variant->abstract) { + unlink(self->server_addr.sock_name); + unlink(self->client_addr->sock_name); + } +} + +static void fill_sockaddr(struct sock_addr *addr, bool abstract) +{ + char *sun_path_buf =3D (char *)&addr->listen_addr.sun_path; + + addr->listen_addr.sun_family =3D AF_UNIX; + addr->addrlen =3D offsetof(struct sockaddr_un, sun_path); + snprintf(addr->sock_name, sizeof(addr->sock_name), "scm_pidfd_%d", getpid= ()); + addr->addrlen +=3D strlen(addr->sock_name); + if (abstract) { + *sun_path_buf =3D '\0'; + addr->addrlen++; + sun_path_buf++; + } else { + unlink(addr->sock_name); + } + memcpy(sun_path_buf, addr->sock_name, strlen(addr->sock_name)); +} + +static void client(FIXTURE_DATA(scm_pidfd) *self, + const FIXTURE_VARIANT(scm_pidfd) *variant) +{ + int err; + int cfd; + socklen_t len; + struct ucred peer_cred; + int peer_pidfd; + pid_t peer_pid; + int on =3D 0; + + cfd =3D socket(AF_UNIX, variant->type, 0); + if (cfd < 0) { + log_err("socket"); + child_die(); + } + + if (variant->type =3D=3D SOCK_DGRAM) { + fill_sockaddr(self->client_addr, variant->abstract); + + if (bind(cfd, (struct sockaddr *)&self->client_addr->listen_addr, self->= client_addr->addrlen)) { + log_err("bind"); + child_die(); + } + } + + if (connect(cfd, (struct sockaddr *)&self->server_addr.listen_addr, + self->server_addr.addrlen) !=3D 0) { + log_err("connect"); + child_die(); + } + + on =3D 1; + if (setsockopt(cfd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on))) { + log_err("Failed to set SO_PASSCRED"); + child_die(); + } + + if (setsockopt(cfd, SOL_SOCKET, SO_PASSPIDFD, &on, sizeof(on))) { + log_err("Failed to set SO_PASSPIDFD"); + child_die(); + } + + close(self->startup_pipe[1]); + + if (cmsg_check(cfd)) { + log_err("cmsg_check failed"); + child_die(); + } + + /* skip further for SOCK_DGRAM as it's not applicable */ + if (variant->type =3D=3D SOCK_DGRAM) + return; + + len =3D sizeof(peer_cred); + if (getsockopt(cfd, SOL_SOCKET, SO_PEERCRED, &peer_cred, &len)) { + log_err("Failed to get SO_PEERCRED"); + child_die(); + } + + len =3D sizeof(peer_pidfd); + if (getsockopt(cfd, SOL_SOCKET, SO_PEERPIDFD, &peer_pidfd, &len)) { + log_err("Failed to get SO_PEERPIDFD"); + child_die(); + } + + /* pid from SO_PEERCRED should point to the parent process PID */ + if (peer_cred.pid !=3D getppid()) { + log_err("peer_cred.pid !=3D getppid(): %d !=3D %d", peer_cred.pid, getpp= id()); + child_die(); + } + + peer_pid =3D get_pid_from_fdinfo_file(peer_pidfd, + "Pid:", sizeof("Pid:") - 1); + if (peer_pid !=3D peer_cred.pid) { + log_err("peer_pid !=3D peer_cred.pid: %d !=3D %d", peer_pid, peer_cred.p= id); + child_die(); + } +} + +TEST_F(scm_pidfd, test) +{ + int err; + int pfd; + int child_status =3D 0; + + self->server =3D socket(AF_UNIX, variant->type, 0); + ASSERT_NE(-1, self->server); + + fill_sockaddr(&self->server_addr, variant->abstract); + + err =3D bind(self->server, (struct sockaddr *)&self->server_addr.listen_a= ddr, self->server_addr.addrlen); + ASSERT_EQ(0, err); + + if (variant->type =3D=3D SOCK_STREAM) { + err =3D listen(self->server, 1); + ASSERT_EQ(0, err); + } + + err =3D pipe(self->startup_pipe); + ASSERT_NE(-1, err); + + self->client_pid =3D fork(); + ASSERT_NE(-1, self->client_pid); + if (self->client_pid =3D=3D 0) { + close(self->server); + close(self->startup_pipe[0]); + client(self, variant); + exit(0); + } + close(self->startup_pipe[1]); + + if (variant->type =3D=3D SOCK_STREAM) { + pfd =3D accept(self->server, NULL, NULL); + ASSERT_NE(-1, pfd); + } else { + pfd =3D self->server; + } + + /* wait until the child arrives at checkpoint */ + read(self->startup_pipe[0], &err, sizeof(int)); + close(self->startup_pipe[0]); + + if (variant->type =3D=3D SOCK_DGRAM) { + err =3D sendto(pfd, "x", sizeof(char), 0, (struct sockaddr *)&self->clie= nt_addr->listen_addr, self->client_addr->addrlen); + ASSERT_NE(-1, err); + } else { + err =3D send(pfd, "x", sizeof(char), 0); + ASSERT_NE(-1, err); + } + + close(pfd); + waitpid(self->client_pid, &child_status, 0); + ASSERT_EQ(0, WIFEXITED(child_status) ? WEXITSTATUS(child_status) : 1); +} + +TEST_HARNESS_MAIN --=20 2.34.1