From: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> Date: Tue, 21 Mar 2023 19:33:42 +0100 > Basic test to check consistency between: > - SCM_CREDENTIALS and SCM_PIDFD > - SO_PEERCRED and SO_PEERPIDFD > > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > Cc: Eric Dumazet <edumazet@xxxxxxxxxx> > Cc: Jakub Kicinski <kuba@xxxxxxxxxx> > Cc: Paolo Abeni <pabeni@xxxxxxxxxx> > Cc: Leon Romanovsky <leon@xxxxxxxxxx> > Cc: David Ahern <dsahern@xxxxxxxxxx> > Cc: Arnd Bergmann <arnd@xxxxxxxx> > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > Cc: Christian Brauner <brauner@xxxxxxxxxx> > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: netdev@xxxxxxxxxxxxxxx > Cc: linux-arch@xxxxxxxxxxxxxxx > Cc: linux-kselftest@xxxxxxxxxxxxxxx > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> > --- > tools/testing/selftests/net/.gitignore | 1 + > tools/testing/selftests/net/af_unix/Makefile | 3 +- > .../testing/selftests/net/af_unix/scm_pidfd.c | 336 ++++++++++++++++++ > 3 files changed, 339 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/selftests/net/.gitignore > index a6911cae368c..f2d23a1df596 100644 > --- a/tools/testing/selftests/net/.gitignore > +++ b/tools/testing/selftests/net/.gitignore > @@ -25,6 +25,7 @@ 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/selftests/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 := diag_uid test_unix_oob unix_connect > +CFLAGS += $(KHDR_INCLUDES) > +TEST_GEN_PROGS := diag_uid test_unix_oob unix_connect scm_pidfd > > include ../../lib.mk > diff --git a/tools/testing/selftests/net/af_unix/scm_pidfd.c b/tools/testing/selftests/net/af_unix/scm_pidfd.c > new file mode 100644 > index 000000000000..fa502510ee9e > --- /dev/null > +++ b/tools/testing/selftests/net/af_unix/scm_pidfd.c > @@ -0,0 +1,336 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#define _GNU_SOURCE > +#include <error.h> > +#include <limits.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <sys/socket.h> > +#include <linux/socket.h> > +#include <unistd.h> > +#include <string.h> > +#include <errno.h> > +#include <sys/un.h> > +#include <sys/signal.h> > +#include <sys/types.h> > +#include <sys/wait.h> #include "../../kselftest_harness.h" Could you rewrite with kselftest ? https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html Also, it would be better to have all combinations as FIXTURE_VARIANT() covered by unix_passcred_enabled() like (self, peer) = (0, 0), (SO_PASSPIDFD, 0), (0, SO_PASSPIDFD), (SO_PASSPIDFD, SO_PASSPIDFD), ... (SO_PASSPIDFD, SO_PEERCRED), ... Thanks, Kuniyuki > + > +#define clean_errno() (errno == 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 pid_t client_pid; > +static char sock_name[32]; > + > +static void die(int status) > +{ > + unlink(sock_name); > + kill(client_pid, SIGTERM); > + exit(status); > +} > + > +static void child_die() > +{ > + kill(getppid(), SIGTERM); > + exit(1); > +} > + > +static int safe_int(const char *numstr, int *converted) > +{ > + char *err = NULL; > + long sli; > + > + errno = 0; > + sli = strtol(numstr, &err, 0); > + if (errno == ERANGE && (sli == LONG_MAX || sli == LONG_MIN)) > + return -ERANGE; > + > + if (errno != 0 && sli == 0) > + return -EINVAL; > + > + if (err == numstr || *err != '\0') > + return -EINVAL; > + > + if (sli > INT_MAX || sli < INT_MIN) > + return -ERANGE; > + > + *converted = (int)sli; > + return 0; > +} > + > +static int char_left_gc(const char *buffer, size_t len) > +{ > + size_t i; > + > + for (i = 0; i < len; i++) { > + if (buffer[i] == ' ' || buffer[i] == '\t') > + continue; > + > + return i; > + } > + > + return 0; > +} > + > +static int char_right_gc(const char *buffer, size_t len) > +{ > + int i; > + > + for (i = len - 1; i >= 0; i--) { > + if (buffer[i] == ' ' || buffer[i] == '\t' || > + buffer[i] == '\n' || buffer[i] == '\0') > + continue; > + > + return i + 1; > + } > + > + return 0; > +} > + > +static char *trim_whitespace_in_place(char *buffer) > +{ > + buffer += char_left_gc(buffer, strlen(buffer)); > + buffer[char_right_gc(buffer, strlen(buffer))] = '\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 keylen) > +{ > + int ret; > + char path[512]; > + FILE *f; > + size_t n = 0; > + pid_t result = -1; > + char *line = NULL; > + > + snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd); > + > + f = fopen(path, "re"); > + if (!f) > + return -1; > + > + while (getline(&line, &n, f) != -1) { > + char *numstr; > + > + if (strncmp(line, key, keylen)) > + continue; > + > + numstr = trim_whitespace_in_place(line + 4); > + ret = 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 = { 0 }; > + struct cmsghdr *cmsg; > + struct iovec iov; > + struct ucred *ucred = NULL; > + int data = 0; > + char control[CMSG_SPACE(sizeof(struct ucred)) + > + CMSG_SPACE(sizeof(int))] = { 0 }; > + int *pidfd = NULL; > + pid_t parent_pid; > + int err; > + > + iov.iov_base = &data; > + iov.iov_len = sizeof(data); > + > + msg.msg_iov = &iov; > + msg.msg_iovlen = 1; > + msg.msg_control = control; > + msg.msg_controllen = sizeof(control); > + > + err = 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 = CMSG_FIRSTHDR(&msg); cmsg != NULL; > + cmsg = CMSG_NXTHDR(&msg, cmsg)) { > + if (cmsg->cmsg_level == SOL_SOCKET && > + cmsg->cmsg_type == SCM_PIDFD) { > + if (cmsg->cmsg_len < sizeof(*pidfd)) { > + log_err("CMSG parse: SCM_PIDFD wrong len"); > + return 1; > + } > + > + pidfd = (void *)CMSG_DATA(cmsg); > + } > + > + if (cmsg->cmsg_level == SOL_SOCKET && > + cmsg->cmsg_type == SCM_CREDENTIALS) { > + if (cmsg->cmsg_len < sizeof(*ucred)) { > + log_err("CMSG parse: SCM_CREDENTIALS wrong len"); > + return 1; > + } > + > + ucred = (void *)CMSG_DATA(cmsg); > + } > + } > + > + /* send(pfd, "x", sizeof(char), 0) */ > + if (data != '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 = > + get_pid_from_fdinfo_file(*pidfd, "Pid:", sizeof("Pid:") - 1); > + if (parent_pid != getppid()) { > + log_err("wrong SCM_PIDFD %d != %d", parent_pid, getppid()); > + return 1; > + } > + > + return 0; > +} > + > +void client(struct sockaddr_un *listen_addr) > +{ > + int cfd; > + socklen_t len; > + struct ucred peer_cred; > + int peer_pidfd; > + pid_t peer_pid; > + int on = 0; > + > + cfd = socket(AF_UNIX, SOCK_STREAM, 0); > + if (cfd < 0) { > + log_err("socket"); > + child_die(); > + } > + > + if (connect(cfd, (struct sockaddr *)listen_addr, > + sizeof(*listen_addr)) != 0) { > + log_err("connect"); > + child_die(); > + } > + > + on = 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(); > + } > + > + if (cmsg_check(cfd)) { > + log_err("cmsg_check failed"); > + child_die(); > + } > + > + len = sizeof(peer_cred); > + if (getsockopt(cfd, SOL_SOCKET, SO_PEERCRED, &peer_cred, &len)) { > + log_err("Failed to get SO_PEERCRED"); > + child_die(); > + } > + > + len = 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 != getppid()) { > + log_err("Failed to get SO_PEERPIDFD"); > + child_die(); > + } > + > + peer_pid = get_pid_from_fdinfo_file(peer_pidfd, > + "Pid:", sizeof("Pid:") - 1); > + if (peer_pid != peer_cred.pid) { > + log_err("Failed to get SO_PEERPIDFD"); > + child_die(); > + } > +} > + > +int main(int argc, char **argv) > +{ > + int lfd, pfd; > + int child_status = 0; > + struct sockaddr_un listen_addr; > + > + lfd = socket(AF_UNIX, SOCK_STREAM, 0); > + if (lfd < 0) { > + perror("socket"); > + exit(1); > + } > + > + memset(&listen_addr, 0, sizeof(listen_addr)); > + listen_addr.sun_family = AF_UNIX; > + sprintf(sock_name, "scm_pidfd_%d", getpid()); > + unlink(sock_name); > + strcpy(listen_addr.sun_path, sock_name); > + > + if ((bind(lfd, (struct sockaddr *)&listen_addr, sizeof(listen_addr))) != > + 0) { > + perror("socket bind failed"); > + exit(1); > + } > + > + if (listen(lfd, 1) < 0) { > + perror("listen"); > + exit(1); > + } > + > + client_pid = fork(); > + if (client_pid < 0) { > + perror("fork"); > + exit(1); > + } > + > + if (client_pid == 0) { > + client(&listen_addr); > + exit(0); > + } > + > + pfd = accept(lfd, NULL, NULL); > + if (pfd < 0) { > + perror("accept"); > + die(1); > + } > + > + if (send(pfd, "x", sizeof(char), 0) < 0) { > + perror("send"); > + die(1); > + } > + > + waitpid(client_pid, &child_status, 0); > + die(WIFEXITED(child_status) ? WEXITSTATUS(child_status) : 1); > + die(0); > +} > \ No newline at end of file > -- > 2.34.1
