Re: [PATCH 04/10] selftests/net: SO_PASSPIDFD_THREAD

---
 tools/testing/selftests/net/af_unix/Makefile    |   2 +
 tools/testing/selftests/net/af_unix/scm_pidfd.c | 269 ++++++++++++++++++++++++
 2 files changed, 271 insertions(+)

diff --git a/tools/testing/selftests/net/af_unix/Makefile b/tools/testing/selftests/net/af_unix/Makefile
index a66f10fb0c23..45b841758f1b 100644
--- a/tools/testing/selftests/net/af_unix/Makefile
+++ b/tools/testing/selftests/net/af_unix/Makefile

@@ -23,6 +23,8 @@ TEST_GEN_FILES := scm_rights_denial_lsm.bpf.o
 include ../../lib.mk
 include ../bpf.mk

+$(OUTPUT)/scm_pidfd: CFLAGS += -pthread
+
 $(OUTPUT)/scm_rights_denial_lsm: $(BPFOBJ)
 $(OUTPUT)/scm_rights_denial_lsm: CFLAGS += -I$(SCRATCH_DIR)/include
 $(OUTPUT)/scm_rights_denial_lsm: LDLIBS += -lelf -lz

diff --git a/tools/testing/selftests/net/af_unix/scm_pidfd.c b/tools/testing/selftests/net/af_unix/scm_pidfd.c
index 2c18b92a2603..019c48e1cdcd 100644
--- a/tools/testing/selftests/net/af_unix/scm_pidfd.c
+++ b/tools/testing/selftests/net/af_unix/scm_pidfd.c

@@ -10,6 +10,7 @@
 #include <unistd.h>
 #include <string.h>
 #include <errno.h>
+#include <pthread.h>
 #include <sys/un.h>
 #include <sys/signal.h>
 #include <sys/types.h>

@@ -27,6 +28,10 @@
 #define SCM_PIDFD 0x04
 #endif

+#ifndef SO_PASSPIDFD_THREAD
+#define SO_PASSPIDFD_THREAD 86
+#endif
+
 #define CHILD_EXIT_CODE_OK 123

 static void child_die()

@@ -553,4 +558,268 @@ TEST_F(scm_pidfd, test)
        close(pfd);
 }

+struct thread_ids {
+       pid_t pid;
+       pid_t tid;
+};
+
+static void *send_ids_thread(void *arg)
+{
+       int fd = *(int *)arg;
+       struct thread_ids ids = {
+               .pid = getpid(),
+               .tid = gettid(),
+       };
+       char sync;
+
+       if (send(fd, &ids, sizeof(ids), 0) != sizeof(ids))
+               return (void *)1;
+
+       /* stay alive until the receiver has looked at our pidfd */
+       if (read(fd, &sync, 1) != 1)
+               return (void *)1;
+
+       return NULL;
+}
+
+static void *send_ids_creds_thread(void *arg)
+{
+       int fd = *(int *)arg;
+       struct thread_ids ids = {
+               .pid = getpid(),
+               .tid = gettid(),
+       };
+       struct ucred ucred = {
+               .pid = getpid(),
+               .uid = getuid(),
+               .gid = getgid(),
+       };
+       char control[CMSG_SPACE(sizeof(ucred))] = { 0 };
+       struct iovec iov;
+       struct msghdr msg = { 0 };
+       struct cmsghdr *cmsg;
+       char sync;
+
+       iov.iov_base = &ids;
+       iov.iov_len = sizeof(ids);
+
+       msg.msg_iov = &iov;
+       msg.msg_iovlen = 1;
+       msg.msg_control = control;
+       msg.msg_controllen = sizeof(control);
+
+       cmsg = CMSG_FIRSTHDR(&msg);
+       cmsg->cmsg_level = SOL_SOCKET;
+       cmsg->cmsg_type = SCM_CREDENTIALS;
+       cmsg->cmsg_len = CMSG_LEN(sizeof(ucred));
+       memcpy(CMSG_DATA(cmsg), &ucred, sizeof(ucred));
+
+       if (sendmsg(fd, &msg, 0) != sizeof(ids))
+               return (void *)1;
+
+       if (read(fd, &sync, 1) != 1)
+               return (void *)1;
+
+       return NULL;
+}
+
+static void thread_client(int fd, int syncfd, void *(*sender)(void *))
+{
+       pthread_t thread;
+       void *ret;
+       char sync;
+
+       /* wait until the receiver enabled SO_PASSPIDFD */
+       if (read(syncfd, &sync, 1) != 1)
+               child_die();
+
+       if (pthread_create(&thread, NULL, sender, &fd))
+               child_die();
+
+       if (pthread_join(thread, &ret) || ret)
+               child_die();
+
+       exit(0);
+}
+
+static int recv_pidfd(int fd, struct thread_ids *ids)
+{
+       char control[CMSG_SPACE(sizeof(int))] = { 0 };
+       struct iovec iov;
+       struct msghdr msg = { 0 };
+       struct cmsghdr *cmsg;
+       int pidfd = -1;
+
+       iov.iov_base = ids;
+       iov.iov_len = sizeof(*ids);
+
+       msg.msg_iov = &iov;
+       msg.msg_iovlen = 1;
+       msg.msg_control = control;
+       msg.msg_controllen = sizeof(control);
+
+       if (recvmsg(fd, &msg, 0) != sizeof(*ids)) {
+               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)
+                       memcpy(&pidfd, CMSG_DATA(cmsg), sizeof(pidfd));
+       }
+
+       return pidfd;
+}
+
+static int thread_pidfd_flow(void *(*sender)(void *), int optname,
+                            struct thread_ids *ids, struct pidfd_info *info)
+{
+       int sk[2];
+       int syncpipe[2];
+       int pidfd;
+       int child_status = 0;
+       pid_t child;
+
+       if (socketpair(AF_UNIX, SOCK_STREAM, 0, sk))
+               return -1;
+
+       if (pipe(syncpipe))
+               return -1;
+
+       child = fork();
+       if (child < 0)
+               return -1;
+
+       if (child == 0) {
+               close(sk[0]);
+               close(syncpipe[1]);
+               thread_client(sk[1], syncpipe[0], sender);
+       }
+       close(sk[1]);
+       close(syncpipe[0]);
+
+       int on = 1;
+
+       if (setsockopt(sk[0], SOL_SOCKET, optname, &on, sizeof(on))) {
+               log_err("Failed to set pidfd passing option");
+               return -1;
+       }
+
+       if (write(syncpipe[1], "1", 1) != 1)
+               return -1;
+       close(syncpipe[1]);
+
+       pidfd = recv_pidfd(sk[0], ids);
+       if (pidfd < 0)
+               return -1;
+
+       info->mask = PIDFD_INFO_PID;
+       if (ioctl(pidfd, PIDFD_GET_INFO, info)) {
+               log_err("ioctl(PIDFD_GET_INFO)");
+               close(pidfd);
+               return -1;
+       }
+       close(pidfd);
+
+       /* release the sending thread */
+       if (write(sk[0], "x", 1) != 1)
+               return -1;
+       close(sk[0]);
+
+       waitpid(child, &child_status, 0);
+       if (!WIFEXITED(child_status) || WEXITSTATUS(child_status))
+               return -1;
+
+       return 0;
+}
+
+static int sockopt_set(int fd, int optname, int val)
+{
+       return setsockopt(fd, SOL_SOCKET, optname, &val, sizeof(val));
+}
+
+static int sockopt_get(int fd, int optname)
+{
+       socklen_t len = sizeof(int);
+       int val = -1;
+
+       if (getsockopt(fd, SOL_SOCKET, optname, &val, &len))
+               return -1;
+
+       return val;
+}
+
+TEST(scm_pidfd_setsockopt_values)
+{
+       int sk[2];
+
+       ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM, 0, sk));
+
+       ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD_THREAD, 1));
+       ASSERT_EQ(1, sockopt_get(sk[0], SO_PASSPIDFD_THREAD));
+       ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD));
+
+       /* The option set last wins. */
+       ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD, 1));
+       ASSERT_EQ(1, sockopt_get(sk[0], SO_PASSPIDFD));
+       ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD_THREAD));
+
+       ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD_THREAD, 1));
+       ASSERT_EQ(1, sockopt_get(sk[0], SO_PASSPIDFD_THREAD));
+       ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD));
+
+       /* Disabling one option leaves the other alone. */
+       ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD, 0));
+       ASSERT_EQ(1, sockopt_get(sk[0], SO_PASSPIDFD_THREAD));
+       ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD_THREAD, 0));
+       ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD));
+       ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD_THREAD));
+
+       close(sk[0]);
+       close(sk[1]);
+}
+
+TEST(scm_pidfd_thread)
+{
+       struct thread_ids ids;
+       struct pidfd_info info;
+
+       ASSERT_EQ(0, thread_pidfd_flow(send_ids_thread, SO_PASSPIDFD_THREAD,
+                                      &ids, &info));
+       ASSERT_NE(ids.pid, ids.tid);
+       EXPECT_EQ(ids.tid, info.pid);
+       EXPECT_EQ(ids.pid, info.tgid);
+}
+
+TEST(scm_pidfd_thread_group)
+{
+       struct thread_ids ids;
+       struct pidfd_info info;
+
+       ASSERT_EQ(0, thread_pidfd_flow(send_ids_thread, SO_PASSPIDFD,
+                                      &ids, &info));
+       ASSERT_NE(ids.pid, ids.tid);
+       EXPECT_EQ(ids.pid, info.pid);
+       EXPECT_EQ(ids.pid, info.tgid);
+}
+
+TEST(scm_pidfd_thread_creds)
+{
+       struct thread_ids ids;
+       struct pidfd_info info;
+
+       ASSERT_EQ(0, thread_pidfd_flow(send_ids_creds_thread, SO_PASSPIDFD_THREAD,
+                                      &ids, &info));
+       ASSERT_NE(ids.pid, ids.tid);
+       EXPECT_EQ(ids.tid, info.pid);
+       EXPECT_EQ(ids.pid, info.tgid);
+}
+
 TEST_HARNESS_MAIN

--

2.53.0