[PATCH 5/5] selftests/coredump: add coredump server selftests

[Christian Brauner <brauner@kernel.org>]

This adds extensive tests for the coredump server.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 tools/testing/selftests/coredump/Makefile         |    2 +-
 tools/testing/selftests/coredump/config           |    4 +
 tools/testing/selftests/coredump/stackdump_test.c | 1110 ++++++++++++++++++++-
 3 files changed, 1114 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/coredump/Makefile b/tools/testing/selftests/coredump/Makefile
index bc287a85b825..77b3665c73c7 100644
--- a/tools/testing/selftests/coredump/Makefile
+++ b/tools/testing/selftests/coredump/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
-CFLAGS = -Wall -O0 $(KHDR_INCLUDES)
+CFLAGS += -Wall -O0 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
 
 TEST_GEN_PROGS := stackdump_test
 TEST_FILES := stackdump
diff --git a/tools/testing/selftests/coredump/config b/tools/testing/selftests/coredump/config
new file mode 100644
index 000000000000..6ce9610b06d0
--- /dev/null
+++ b/tools/testing/selftests/coredump/config
@@ -0,0 +1,4 @@
+CONFIG_AF_UNIX_OOB=y
+CONFIG_COREDUMP=y
+CONFIG_NET=y
+CONFIG_UNIX=y
diff --git a/tools/testing/selftests/coredump/stackdump_test.c b/tools/testing/selftests/coredump/stackdump_test.c
index 4d922e5f89fe..a797a90c24b6 100644
--- a/tools/testing/selftests/coredump/stackdump_test.c
+++ b/tools/testing/selftests/coredump/stackdump_test.c
@@ -4,10 +4,14 @@
 #include <fcntl.h>
 #include <inttypes.h>
 #include <libgen.h>
+#include <linux/coredump.h>
+#include <linux/fs.h>
 #include <linux/limits.h>
 #include <pthread.h>
 #include <string.h>
 #include <sys/mount.h>
+#include <poll.h>
+#include <sys/epoll.h>
 #include <sys/resource.h>
 #include <sys/stat.h>
 #include <sys/socket.h>
@@ -15,6 +19,7 @@
 #include <unistd.h>
 
 #include "../kselftest_harness.h"
+#include "../filesystems/wrappers.h"
 #include "../pidfd/pidfd.h"
 
 #define STACKDUMP_FILE "stack_values"
@@ -49,14 +54,32 @@ FIXTURE(coredump)
 {
 	char original_core_pattern[256];
 	pid_t pid_coredump_server;
+	int fd_tmpfs_detached;
 };
 
+static int create_detached_tmpfs(void)
+{
+	int fd_context, fd_tmpfs;
+
+	fd_context = sys_fsopen("tmpfs", 0);
+	if (fd_context < 0)
+		return -1;
+
+	if (sys_fsconfig(fd_context, FSCONFIG_CMD_CREATE, NULL, NULL, 0) < 0)
+		return -1;
+
+	fd_tmpfs = sys_fsmount(fd_context, 0, 0);
+	close(fd_context);
+	return fd_tmpfs;
+}
+
 FIXTURE_SETUP(coredump)
 {
 	FILE *file;
 	int ret;
 
 	self->pid_coredump_server = -ESRCH;
+	self->fd_tmpfs_detached = -1;
 	file = fopen("/proc/sys/kernel/core_pattern", "r");
 	ASSERT_NE(NULL, file);
 
@@ -65,6 +88,8 @@ FIXTURE_SETUP(coredump)
 	ASSERT_LT(ret, sizeof(self->original_core_pattern));
 
 	self->original_core_pattern[ret] = '\0';
+	self->fd_tmpfs_detached = create_detached_tmpfs();
+	ASSERT_GE(self->fd_tmpfs_detached, 0);
 
 	ret = fclose(file);
 	ASSERT_EQ(0, ret);
@@ -103,6 +128,15 @@ FIXTURE_TEARDOWN(coredump)
 		goto fail;
 	}
 
+	if (self->fd_tmpfs_detached >= 0) {
+		ret = close(self->fd_tmpfs_detached);
+		if (ret < 0) {
+			reason = "Unable to close detached tmpfs";
+			goto fail;
+		}
+		self->fd_tmpfs_detached = -1;
+	}
+
 	return;
 fail:
 	/* This should never happen */
@@ -192,7 +226,7 @@ static int create_and_listen_unix_socket(const char *path)
 	if (ret < 0)
 		goto out;
 
-	ret = listen(fd, 1);
+	ret = listen(fd, 128);
 	if (ret < 0)
 		goto out;
 
@@ -551,4 +585,1078 @@ TEST_F(coredump, socket_no_listener)
 	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
 }
 
+int recv_oob_marker(int fd)
+{
+	uint8_t oob_marker;
+	ssize_t ret;
+
+	ret = recv(fd, &oob_marker, 1, MSG_OOB);
+	if (ret < 0)
+		return -1;
+	if (ret > 1 || ret == 0)
+		return -EINVAL;
+
+	switch (oob_marker) {
+	case COREDUMP_OOB_INVALIDSIZE:
+		fprintf(stderr, "Received OOB marker: InvalidSize\n");
+		return COREDUMP_OOB_INVALIDSIZE;
+	case COREDUMP_OOB_UNSUPPORTED:
+		fprintf(stderr, "Received OOB marker: Unsupported\n");
+		return COREDUMP_OOB_UNSUPPORTED;
+	case COREDUMP_OOB_CONFLICTING:
+		fprintf(stderr, "Received OOB marker: Conflicting\n");
+		return COREDUMP_OOB_CONFLICTING;
+	default:
+		fprintf(stderr, "Received unknown OOB marker: %u\n", oob_marker);
+		break;
+	}
+	return -1;
+}
+
+static bool is_msg_oob_supported(void)
+{
+	int sv[2];
+	char c = 'X';
+	int ret;
+	static int supported = -1;
+
+	if (supported >= 0)
+		return supported == 1;
+
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) < 0)
+		return false;
+
+	ret = send(sv[0], &c, 1, MSG_OOB);
+	close(sv[0]);
+	close(sv[1]);
+
+	if (ret < 0) {
+		if (errno == EINVAL || errno == EOPNOTSUPP) {
+			supported = 0;
+			return false;
+		}
+
+		return false;
+	}
+	supported = 1;
+	return true;
+}
+
+static bool wait_for_oob_marker(int fd, enum coredump_oob oob_marker)
+{
+	ssize_t ret;
+	struct pollfd pfd = {
+		.fd = fd,
+		.events = POLLPRI,
+		.revents = 0,
+	};
+
+	if (!is_msg_oob_supported())
+		return true;
+
+	ret = poll(&pfd, 1, -1);
+	if (ret < 0)
+		return false;
+	if (!(pfd.revents & POLLPRI))
+		return false;
+	if (pfd.revents & POLLERR)
+		return false;
+	if (pfd.revents & POLLHUP)
+		return false;
+
+	ret = recv_oob_marker(fd);
+	if (ret < 0)
+		return false;
+	return ret == oob_marker;
+}
+
+static bool read_coredump_req(int fd, struct coredump_req *req)
+{
+	ssize_t ret;
+	size_t field_size, user_size, ack_size, kernel_size, remaining_size;
+
+	memset(req, 0, sizeof(*req));
+	field_size = sizeof(req->size);
+
+	/* Peek the size of the coredump request. */
+	ret = recv(fd, req, field_size, MSG_PEEK | MSG_WAITALL);
+	if (ret != field_size)
+		return false;
+	kernel_size = req->size;
+
+	if (kernel_size < COREDUMP_ACK_SIZE_VER0)
+		return false;
+	if (kernel_size >= PAGE_SIZE)
+		return false;
+
+	/* Use the minimum of user and kernel size to read the full request. */
+	user_size = sizeof(struct coredump_req);
+	ack_size = user_size < kernel_size ? user_size : kernel_size;
+	ret = recv(fd, req, ack_size, MSG_WAITALL);
+	if (ret != ack_size)
+		return false;
+
+	fprintf(stderr, "Read coredump request with size %u and mask 0x%llx\n",
+		req->size, (unsigned long long)req->mask);
+
+	if (user_size > kernel_size)
+		remaining_size = user_size - kernel_size;
+	else
+		remaining_size = kernel_size - user_size;
+
+	if (PAGE_SIZE <= remaining_size)
+		return false;
+
+	/*
+	 * Discard any additional data if the kernel's request was larger than
+	 * what we knew about or cared about.
+	 */
+	if (remaining_size) {
+		char buffer[PAGE_SIZE];
+
+		ret = recv(fd, buffer, sizeof(buffer), MSG_WAITALL);
+		if (ret != remaining_size)
+			return false;
+		fprintf(stderr, "Discarded %zu bytes of non-OOB data after coredump request\n", remaining_size);
+	}
+
+	return true;
+}
+
+static bool send_coredump_ack(int fd, const struct coredump_req *req,
+			      __u64 mask, size_t size_ack)
+{
+	ssize_t ret;
+	/*
+	 * Wrap struct coredump_ack in a larger struct so we can
+	 * simulate sending to much data to the kernel.
+	 */
+	struct large_ack_for_size_testing {
+		struct coredump_ack ack;
+		char buffer[PAGE_SIZE];
+	} large_ack = {};
+
+	if (!size_ack)
+		size_ack = sizeof(struct coredump_ack) < req->size_ack ?
+				   sizeof(struct coredump_ack) :
+				   req->size_ack;
+	large_ack.ack.mask = mask;
+	large_ack.ack.size = size_ack;
+	ret = send(fd, &large_ack, size_ack, MSG_NOSIGNAL);
+	if (ret != size_ack)
+		return false;
+
+	fprintf(stderr, "Sent coredump ack with size %zu and mask 0x%llx\n",
+		size_ack, (unsigned long long)mask);
+	return true;
+}
+
+static bool check_coredump_req(const struct coredump_req *req, size_t min_size,
+			       __u64 required_mask)
+{
+	if (req->size < min_size)
+		return false;
+	if ((req->mask & required_mask) != required_mask)
+		return false;
+	if (req->mask & ~required_mask)
+		return false;
+	return true;
+}
+
+TEST_F(coredump, socket_request_kernel)
+{
+	int pidfd, ret, status;
+	pid_t pid, pid_coredump_server;
+	struct stat st;
+	struct pidfd_info info = {};
+	int ipc_sockets[2];
+	char c;
+
+	ASSERT_TRUE(set_core_pattern("@@/tmp/coredump.socket"));
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+	ASSERT_EQ(ret, 0);
+
+	pid_coredump_server = fork();
+	ASSERT_GE(pid_coredump_server, 0);
+	if (pid_coredump_server == 0) {
+		struct coredump_req req = {};
+		int fd_server = -1, fd_coredump = -1, fd_core_file = -1, fd_peer_pidfd = -1;
+		int exit_code = EXIT_FAILURE;
+
+		close(ipc_sockets[0]);
+
+		fd_server = create_and_listen_unix_socket("/tmp/coredump.socket");
+		if (fd_server < 0)
+			goto out;
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+			goto out;
+
+		close(ipc_sockets[1]);
+
+		fd_coredump = accept4(fd_server, NULL, NULL, SOCK_CLOEXEC);
+		if (fd_coredump < 0)
+			goto out;
+
+		fd_peer_pidfd = get_peer_pidfd(fd_coredump);
+		if (fd_peer_pidfd < 0)
+			goto out;
+
+		if (!get_pidfd_info(fd_peer_pidfd, &info))
+			goto out;
+
+		if (!(info.mask & PIDFD_INFO_COREDUMP))
+			goto out;
+
+		if (!(info.coredump_mask & PIDFD_COREDUMPED))
+			goto out;
+
+		fd_core_file = creat("/tmp/coredump.file", 0644);
+		if (fd_core_file < 0)
+			goto out;
+
+		if (!read_coredump_req(fd_coredump, &req))
+			goto out;
+
+		if (!check_coredump_req(&req, COREDUMP_ACK_SIZE_VER0,
+					COREDUMP_KERNEL | COREDUMP_USERSPACE |
+					COREDUMP_REJECT | COREDUMP_WAIT))
+			goto out;
+
+		if (!send_coredump_ack(fd_coredump, &req,
+				       COREDUMP_KERNEL | COREDUMP_WAIT, 0))
+			goto out;
+
+		for (;;) {
+			char buffer[4096];
+			ssize_t bytes_read, bytes_write;
+
+			bytes_read = read(fd_coredump, buffer, sizeof(buffer));
+			if (bytes_read < 0)
+				goto out;
+
+			if (bytes_read == 0)
+				break;
+
+			bytes_write = write(fd_core_file, buffer, bytes_read);
+			if (bytes_read != bytes_write)
+				goto out;
+		}
+
+		exit_code = EXIT_SUCCESS;
+out:
+		if (fd_core_file >= 0)
+			close(fd_core_file);
+		if (fd_peer_pidfd >= 0)
+			close(fd_peer_pidfd);
+		if (fd_coredump >= 0)
+			close(fd_coredump);
+		if (fd_server >= 0)
+			close(fd_server);
+		_exit(exit_code);
+	}
+	self->pid_coredump_server = pid_coredump_server;
+
+	EXPECT_EQ(close(ipc_sockets[1]), 0);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+	if (pid == 0)
+		crashing_child();
+
+	pidfd = sys_pidfd_open(pid, 0);
+	ASSERT_GE(pidfd, 0);
+
+	waitpid(pid, &status, 0);
+	ASSERT_TRUE(WIFSIGNALED(status));
+	ASSERT_TRUE(WCOREDUMP(status));
+
+	ASSERT_TRUE(get_pidfd_info(pidfd, &info));
+	ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0);
+	ASSERT_GT((info.coredump_mask & PIDFD_COREDUMPED), 0);
+
+	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
+
+	ASSERT_EQ(stat("/tmp/coredump.file", &st), 0);
+	ASSERT_GT(st.st_size, 0);
+	system("file /tmp/coredump.file");
+}
+
+TEST_F(coredump, socket_request_userspace)
+{
+	int pidfd, ret, status;
+	pid_t pid, pid_coredump_server;
+	struct pidfd_info info = {};
+	int ipc_sockets[2];
+	char c;
+
+	ASSERT_TRUE(set_core_pattern("@@/tmp/coredump.socket"));
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+	ASSERT_EQ(ret, 0);
+
+	pid_coredump_server = fork();
+	ASSERT_GE(pid_coredump_server, 0);
+	if (pid_coredump_server == 0) {
+		struct coredump_req req = {};
+		int fd_server = -1, fd_coredump = -1, fd_peer_pidfd = -1;
+		int exit_code = EXIT_FAILURE;
+
+		close(ipc_sockets[0]);
+
+		fd_server = create_and_listen_unix_socket("/tmp/coredump.socket");
+		if (fd_server < 0)
+			goto out;
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+			goto out;
+
+		close(ipc_sockets[1]);
+
+		fd_coredump = accept4(fd_server, NULL, NULL, SOCK_CLOEXEC);
+		if (fd_coredump < 0)
+			goto out;
+
+		fd_peer_pidfd = get_peer_pidfd(fd_coredump);
+		if (fd_peer_pidfd < 0)
+			goto out;
+
+		if (!get_pidfd_info(fd_peer_pidfd, &info))
+			goto out;
+
+		if (!(info.mask & PIDFD_INFO_COREDUMP))
+			goto out;
+
+		if (!(info.coredump_mask & PIDFD_COREDUMPED))
+			goto out;
+
+		if (!read_coredump_req(fd_coredump, &req))
+			goto out;
+
+		if (!check_coredump_req(&req, COREDUMP_ACK_SIZE_VER0,
+					COREDUMP_KERNEL | COREDUMP_USERSPACE |
+					COREDUMP_REJECT | COREDUMP_WAIT))
+			goto out;
+
+		if (!send_coredump_ack(fd_coredump, &req,
+				       COREDUMP_USERSPACE | COREDUMP_WAIT, 0))
+			goto out;
+
+		for (;;) {
+			char buffer[4096];
+			ssize_t bytes_read;
+
+			bytes_read = read(fd_coredump, buffer, sizeof(buffer));
+			if (bytes_read > 0)
+				goto out;
+
+			if (bytes_read < 0)
+				goto out;
+
+			if (bytes_read == 0)
+				break;
+		}
+
+		exit_code = EXIT_SUCCESS;
+out:
+		if (fd_peer_pidfd >= 0)
+			close(fd_peer_pidfd);
+		if (fd_coredump >= 0)
+			close(fd_coredump);
+		if (fd_server >= 0)
+			close(fd_server);
+		_exit(exit_code);
+	}
+	self->pid_coredump_server = pid_coredump_server;
+
+	EXPECT_EQ(close(ipc_sockets[1]), 0);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+	if (pid == 0)
+		crashing_child();
+
+	pidfd = sys_pidfd_open(pid, 0);
+	ASSERT_GE(pidfd, 0);
+
+	waitpid(pid, &status, 0);
+	ASSERT_TRUE(WIFSIGNALED(status));
+	ASSERT_TRUE(WCOREDUMP(status));
+
+	ASSERT_TRUE(get_pidfd_info(pidfd, &info));
+	ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0);
+	ASSERT_GT((info.coredump_mask & PIDFD_COREDUMPED), 0);
+
+	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
+}
+
+TEST_F(coredump, socket_request_reject)
+{
+	int pidfd, ret, status;
+	pid_t pid, pid_coredump_server;
+	struct pidfd_info info = {};
+	int ipc_sockets[2];
+	char c;
+
+	ASSERT_TRUE(set_core_pattern("@@/tmp/coredump.socket"));
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+	ASSERT_EQ(ret, 0);
+
+	pid_coredump_server = fork();
+	ASSERT_GE(pid_coredump_server, 0);
+	if (pid_coredump_server == 0) {
+		struct coredump_req req = {};
+		int fd_server = -1, fd_coredump = -1, fd_peer_pidfd = -1;
+		int exit_code = EXIT_FAILURE;
+
+		close(ipc_sockets[0]);
+
+		fd_server = create_and_listen_unix_socket("/tmp/coredump.socket");
+		if (fd_server < 0)
+			goto out;
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+			goto out;
+
+		close(ipc_sockets[1]);
+
+		fd_coredump = accept4(fd_server, NULL, NULL, SOCK_CLOEXEC);
+		if (fd_coredump < 0)
+			goto out;
+
+		fd_peer_pidfd = get_peer_pidfd(fd_coredump);
+		if (fd_peer_pidfd < 0)
+			goto out;
+
+		if (!get_pidfd_info(fd_peer_pidfd, &info))
+			goto out;
+
+		if (!(info.mask & PIDFD_INFO_COREDUMP))
+			goto out;
+
+		if (!(info.coredump_mask & PIDFD_COREDUMPED))
+			goto out;
+
+		if (!read_coredump_req(fd_coredump, &req))
+			goto out;
+
+		if (!check_coredump_req(&req, COREDUMP_ACK_SIZE_VER0,
+					COREDUMP_KERNEL | COREDUMP_USERSPACE |
+					COREDUMP_REJECT | COREDUMP_WAIT))
+			goto out;
+
+		if (!send_coredump_ack(fd_coredump, &req,
+				       COREDUMP_REJECT | COREDUMP_WAIT, 0))
+			goto out;
+
+		for (;;) {
+			char buffer[4096];
+			ssize_t bytes_read;
+
+			bytes_read = read(fd_coredump, buffer, sizeof(buffer));
+			if (bytes_read > 0)
+				goto out;
+
+			if (bytes_read < 0)
+				goto out;
+
+			if (bytes_read == 0)
+				break;
+		}
+
+		exit_code = EXIT_SUCCESS;
+out:
+		if (fd_peer_pidfd >= 0)
+			close(fd_peer_pidfd);
+		if (fd_coredump >= 0)
+			close(fd_coredump);
+		if (fd_server >= 0)
+			close(fd_server);
+		_exit(exit_code);
+	}
+	self->pid_coredump_server = pid_coredump_server;
+
+	EXPECT_EQ(close(ipc_sockets[1]), 0);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+	if (pid == 0)
+		crashing_child();
+
+	pidfd = sys_pidfd_open(pid, 0);
+	ASSERT_GE(pidfd, 0);
+
+	waitpid(pid, &status, 0);
+	ASSERT_TRUE(WIFSIGNALED(status));
+	ASSERT_FALSE(WCOREDUMP(status));
+
+	ASSERT_TRUE(get_pidfd_info(pidfd, &info));
+	ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0);
+	ASSERT_GT((info.coredump_mask & PIDFD_COREDUMPED), 0);
+
+	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
+}
+
+TEST_F(coredump, socket_request_invalid_flag_combination)
+{
+	int pidfd, ret, status;
+	pid_t pid, pid_coredump_server;
+	struct pidfd_info info = {};
+	int ipc_sockets[2];
+	char c;
+
+	ASSERT_TRUE(set_core_pattern("@@/tmp/coredump.socket"));
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+	ASSERT_EQ(ret, 0);
+
+	pid_coredump_server = fork();
+	ASSERT_GE(pid_coredump_server, 0);
+	if (pid_coredump_server == 0) {
+		struct coredump_req req = {};
+		int fd_server = -1, fd_coredump = -1, fd_peer_pidfd = -1;
+		int exit_code = EXIT_FAILURE;
+
+		close(ipc_sockets[0]);
+
+		fd_server = create_and_listen_unix_socket("/tmp/coredump.socket");
+		if (fd_server < 0)
+			goto out;
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+			goto out;
+
+		close(ipc_sockets[1]);
+
+		fd_coredump = accept4(fd_server, NULL, NULL, SOCK_CLOEXEC);
+		if (fd_coredump < 0)
+			goto out;
+
+		fd_peer_pidfd = get_peer_pidfd(fd_coredump);
+		if (fd_peer_pidfd < 0)
+			goto out;
+
+		if (!get_pidfd_info(fd_peer_pidfd, &info))
+			goto out;
+
+		if (!(info.mask & PIDFD_INFO_COREDUMP))
+			goto out;
+
+		if (!(info.coredump_mask & PIDFD_COREDUMPED))
+			goto out;
+
+		if (!read_coredump_req(fd_coredump, &req))
+			goto out;
+
+		if (!check_coredump_req(&req, COREDUMP_ACK_SIZE_VER0,
+					COREDUMP_KERNEL | COREDUMP_USERSPACE |
+					COREDUMP_REJECT | COREDUMP_WAIT))
+			goto out;
+
+		if (!send_coredump_ack(fd_coredump, &req,
+				       COREDUMP_KERNEL | COREDUMP_REJECT | COREDUMP_WAIT, 0))
+			goto out;
+
+		if (!wait_for_oob_marker(fd_coredump, COREDUMP_OOB_CONFLICTING))
+			goto out;
+
+		exit_code = EXIT_SUCCESS;
+out:
+		if (fd_peer_pidfd >= 0)
+			close(fd_peer_pidfd);
+		if (fd_coredump >= 0)
+			close(fd_coredump);
+		if (fd_server >= 0)
+			close(fd_server);
+		_exit(exit_code);
+	}
+	self->pid_coredump_server = pid_coredump_server;
+
+	EXPECT_EQ(close(ipc_sockets[1]), 0);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+	if (pid == 0)
+		crashing_child();
+
+	pidfd = sys_pidfd_open(pid, 0);
+	ASSERT_GE(pidfd, 0);
+
+	waitpid(pid, &status, 0);
+	ASSERT_TRUE(WIFSIGNALED(status));
+	ASSERT_FALSE(WCOREDUMP(status));
+
+	ASSERT_TRUE(get_pidfd_info(pidfd, &info));
+	ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0);
+	ASSERT_GT((info.coredump_mask & PIDFD_COREDUMPED), 0);
+
+	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
+}
+
+TEST_F(coredump, socket_request_unknown_flag)
+{
+	int pidfd, ret, status;
+	pid_t pid, pid_coredump_server;
+	struct pidfd_info info = {};
+	int ipc_sockets[2];
+	char c;
+
+	ASSERT_TRUE(set_core_pattern("@@/tmp/coredump.socket"));
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+	ASSERT_EQ(ret, 0);
+
+	pid_coredump_server = fork();
+	ASSERT_GE(pid_coredump_server, 0);
+	if (pid_coredump_server == 0) {
+		struct coredump_req req = {};
+		int fd_server = -1, fd_coredump = -1, fd_peer_pidfd = -1;
+		int exit_code = EXIT_FAILURE;
+
+		close(ipc_sockets[0]);
+
+		fd_server = create_and_listen_unix_socket("/tmp/coredump.socket");
+		if (fd_server < 0)
+			goto out;
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+			goto out;
+
+		close(ipc_sockets[1]);
+
+		fd_coredump = accept4(fd_server, NULL, NULL, SOCK_CLOEXEC);
+		if (fd_coredump < 0)
+			goto out;
+
+		fd_peer_pidfd = get_peer_pidfd(fd_coredump);
+		if (fd_peer_pidfd < 0)
+			goto out;
+
+		if (!get_pidfd_info(fd_peer_pidfd, &info))
+			goto out;
+
+		if (!(info.mask & PIDFD_INFO_COREDUMP))
+			goto out;
+
+		if (!(info.coredump_mask & PIDFD_COREDUMPED))
+			goto out;
+
+		if (!read_coredump_req(fd_coredump, &req))
+			goto out;
+
+		if (!check_coredump_req(&req, COREDUMP_ACK_SIZE_VER0,
+					COREDUMP_KERNEL | COREDUMP_USERSPACE |
+					COREDUMP_REJECT | COREDUMP_WAIT))
+			goto out;
+
+		if (!send_coredump_ack(fd_coredump, &req, (1ULL << 63), 0))
+			goto out;
+
+		if (!wait_for_oob_marker(fd_coredump, COREDUMP_OOB_UNSUPPORTED))
+			goto out;
+
+		exit_code = EXIT_SUCCESS;
+out:
+		if (fd_peer_pidfd >= 0)
+			close(fd_peer_pidfd);
+		if (fd_coredump >= 0)
+			close(fd_coredump);
+		if (fd_server >= 0)
+			close(fd_server);
+		_exit(exit_code);
+	}
+	self->pid_coredump_server = pid_coredump_server;
+
+	EXPECT_EQ(close(ipc_sockets[1]), 0);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+	if (pid == 0)
+		crashing_child();
+
+	pidfd = sys_pidfd_open(pid, 0);
+	ASSERT_GE(pidfd, 0);
+
+	waitpid(pid, &status, 0);
+	ASSERT_TRUE(WIFSIGNALED(status));
+	ASSERT_FALSE(WCOREDUMP(status));
+
+	ASSERT_TRUE(get_pidfd_info(pidfd, &info));
+	ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0);
+	ASSERT_GT((info.coredump_mask & PIDFD_COREDUMPED), 0);
+
+	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
+}
+
+TEST_F(coredump, socket_request_invalid_size_small)
+{
+	int pidfd, ret, status;
+	pid_t pid, pid_coredump_server;
+	struct pidfd_info info = {};
+	int ipc_sockets[2];
+	char c;
+
+	ASSERT_TRUE(set_core_pattern("@@/tmp/coredump.socket"));
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+	ASSERT_EQ(ret, 0);
+
+	pid_coredump_server = fork();
+	ASSERT_GE(pid_coredump_server, 0);
+	if (pid_coredump_server == 0) {
+		struct coredump_req req = {};
+		int fd_server = -1, fd_coredump = -1, fd_peer_pidfd = -1;
+		int exit_code = EXIT_FAILURE;
+
+		close(ipc_sockets[0]);
+
+		fd_server = create_and_listen_unix_socket("/tmp/coredump.socket");
+		if (fd_server < 0)
+			goto out;
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+			goto out;
+
+		close(ipc_sockets[1]);
+
+		fd_coredump = accept4(fd_server, NULL, NULL, SOCK_CLOEXEC);
+		if (fd_coredump < 0)
+			goto out;
+
+		fd_peer_pidfd = get_peer_pidfd(fd_coredump);
+		if (fd_peer_pidfd < 0)
+			goto out;
+
+		if (!get_pidfd_info(fd_peer_pidfd, &info))
+			goto out;
+
+		if (!(info.mask & PIDFD_INFO_COREDUMP))
+			goto out;
+
+		if (!(info.coredump_mask & PIDFD_COREDUMPED))
+			goto out;
+
+		if (!read_coredump_req(fd_coredump, &req))
+			goto out;
+
+		if (!check_coredump_req(&req, COREDUMP_ACK_SIZE_VER0,
+					COREDUMP_KERNEL | COREDUMP_USERSPACE |
+					COREDUMP_REJECT | COREDUMP_WAIT))
+			goto out;
+
+		if (!send_coredump_ack(fd_coredump, &req,
+				       COREDUMP_REJECT | COREDUMP_WAIT,
+				       COREDUMP_ACK_SIZE_VER0 / 2))
+			goto out;
+
+		if (!wait_for_oob_marker(fd_coredump, COREDUMP_OOB_INVALIDSIZE))
+			goto out;
+
+		exit_code = EXIT_SUCCESS;
+out:
+		if (fd_peer_pidfd >= 0)
+			close(fd_peer_pidfd);
+		if (fd_coredump >= 0)
+			close(fd_coredump);
+		if (fd_server >= 0)
+			close(fd_server);
+		_exit(exit_code);
+	}
+	self->pid_coredump_server = pid_coredump_server;
+
+	EXPECT_EQ(close(ipc_sockets[1]), 0);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+	if (pid == 0)
+		crashing_child();
+
+	pidfd = sys_pidfd_open(pid, 0);
+	ASSERT_GE(pidfd, 0);
+
+	waitpid(pid, &status, 0);
+	ASSERT_TRUE(WIFSIGNALED(status));
+	ASSERT_FALSE(WCOREDUMP(status));
+
+	ASSERT_TRUE(get_pidfd_info(pidfd, &info));
+	ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0);
+	ASSERT_GT((info.coredump_mask & PIDFD_COREDUMPED), 0);
+
+	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
+}
+
+TEST_F(coredump, socket_request_invalid_size_large)
+{
+	int pidfd, ret, status;
+	pid_t pid, pid_coredump_server;
+	struct pidfd_info info = {};
+	int ipc_sockets[2];
+	char c;
+
+	ASSERT_TRUE(set_core_pattern("@@/tmp/coredump.socket"));
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+	ASSERT_EQ(ret, 0);
+
+	pid_coredump_server = fork();
+	ASSERT_GE(pid_coredump_server, 0);
+	if (pid_coredump_server == 0) {
+		struct coredump_req req = {};
+		int fd_server = -1, fd_coredump = -1, fd_peer_pidfd = -1;
+		int exit_code = EXIT_FAILURE;
+
+		close(ipc_sockets[0]);
+
+		fd_server = create_and_listen_unix_socket("/tmp/coredump.socket");
+		if (fd_server < 0)
+			goto out;
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+			goto out;
+
+		close(ipc_sockets[1]);
+
+		fd_coredump = accept4(fd_server, NULL, NULL, SOCK_CLOEXEC);
+		if (fd_coredump < 0)
+			goto out;
+
+		fd_peer_pidfd = get_peer_pidfd(fd_coredump);
+		if (fd_peer_pidfd < 0)
+			goto out;
+
+		if (!get_pidfd_info(fd_peer_pidfd, &info))
+			goto out;
+
+		if (!(info.mask & PIDFD_INFO_COREDUMP))
+			goto out;
+
+		if (!(info.coredump_mask & PIDFD_COREDUMPED))
+			goto out;
+
+		if (!read_coredump_req(fd_coredump, &req))
+			goto out;
+
+		if (!check_coredump_req(&req, COREDUMP_ACK_SIZE_VER0,
+					COREDUMP_KERNEL | COREDUMP_USERSPACE |
+					COREDUMP_REJECT | COREDUMP_WAIT))
+			goto out;
+
+		if (!send_coredump_ack(fd_coredump, &req,
+				       COREDUMP_REJECT | COREDUMP_WAIT,
+				       COREDUMP_ACK_SIZE_VER0 + PAGE_SIZE))
+			goto out;
+
+		if (!wait_for_oob_marker(fd_coredump, COREDUMP_OOB_INVALIDSIZE))
+			goto out;
+
+		exit_code = EXIT_SUCCESS;
+out:
+		if (fd_peer_pidfd >= 0)
+			close(fd_peer_pidfd);
+		if (fd_coredump >= 0)
+			close(fd_coredump);
+		if (fd_server >= 0)
+			close(fd_server);
+		_exit(exit_code);
+	}
+	self->pid_coredump_server = pid_coredump_server;
+
+	EXPECT_EQ(close(ipc_sockets[1]), 0);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+	if (pid == 0)
+		crashing_child();
+
+	pidfd = sys_pidfd_open(pid, 0);
+	ASSERT_GE(pidfd, 0);
+
+	waitpid(pid, &status, 0);
+	ASSERT_TRUE(WIFSIGNALED(status));
+	ASSERT_FALSE(WCOREDUMP(status));
+
+	ASSERT_TRUE(get_pidfd_info(pidfd, &info));
+	ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0);
+	ASSERT_GT((info.coredump_mask & PIDFD_COREDUMPED), 0);
+
+	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
+}
+
+
+static int open_coredump_tmpfile(int fd_tmpfs_detached)
+{
+	return openat(fd_tmpfs_detached, ".", O_TMPFILE | O_RDWR | O_EXCL, 0600);
+}
+
+#define NUM_CRASHING_COREDUMPS 5
+
+TEST_F_TIMEOUT(coredump, socket_multiple_crashing_coredumps, 500)
+{
+	int pidfd[NUM_CRASHING_COREDUMPS], status[NUM_CRASHING_COREDUMPS];
+	pid_t pid[NUM_CRASHING_COREDUMPS], pid_coredump_server;
+	struct pidfd_info info = {};
+	int ipc_sockets[2];
+	char c;
+
+	ASSERT_TRUE(set_core_pattern("@@/tmp/coredump.socket"));
+
+	ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets), 0);
+
+	pid_coredump_server = fork();
+	ASSERT_GE(pid_coredump_server, 0);
+	if (pid_coredump_server == 0) {
+		int fd_server = -1, fd_coredump = -1, fd_peer_pidfd = -1, fd_core_file = -1;
+		int exit_code = EXIT_FAILURE;
+		struct coredump_req req = {};
+
+		close(ipc_sockets[0]);
+		fd_server = create_and_listen_unix_socket("/tmp/coredump.socket");
+		if (fd_server < 0) {
+			fprintf(stderr, "Failed to create and listen on unix socket\n");
+			goto out;
+		}
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0) {
+			fprintf(stderr, "Failed to notify parent via ipc socket\n");
+			goto out;
+		}
+		close(ipc_sockets[1]);
+
+		for (int i = 0; i < NUM_CRASHING_COREDUMPS; i++) {
+			fd_coredump = accept4(fd_server, NULL, NULL, SOCK_CLOEXEC);
+			if (fd_coredump < 0) {
+				fprintf(stderr, "accept4 failed: %m\n");
+				goto out;
+			}
+
+			fd_peer_pidfd = get_peer_pidfd(fd_coredump);
+			if (fd_peer_pidfd < 0) {
+				fprintf(stderr, "get_peer_pidfd failed for fd %d: %m\n", fd_coredump);
+				goto out;
+			}
+
+			if (!get_pidfd_info(fd_peer_pidfd, &info)) {
+				fprintf(stderr, "get_pidfd_info failed for fd %d\n", fd_peer_pidfd);
+				goto out;
+			}
+
+			if (!(info.mask & PIDFD_INFO_COREDUMP)) {
+				fprintf(stderr, "pidfd info missing PIDFD_INFO_COREDUMP for fd %d\n", fd_peer_pidfd);
+				goto out;
+			}
+			if (!(info.coredump_mask & PIDFD_COREDUMPED)) {
+				fprintf(stderr, "pidfd info missing PIDFD_COREDUMPED for fd %d\n", fd_peer_pidfd);
+				goto out;
+			}
+
+			if (!read_coredump_req(fd_coredump, &req)) {
+				fprintf(stderr, "read_coredump_req failed for fd %d\n", fd_coredump);
+				goto out;
+			}
+
+			if (!check_coredump_req(&req, COREDUMP_ACK_SIZE_VER0,
+						COREDUMP_KERNEL | COREDUMP_USERSPACE |
+						COREDUMP_REJECT | COREDUMP_WAIT)) {
+				fprintf(stderr, "check_coredump_req failed for fd %d\n", fd_coredump);
+				goto out;
+			}
+
+			if (!send_coredump_ack(fd_coredump, &req,
+					       COREDUMP_KERNEL | COREDUMP_WAIT, 0)) {
+				fprintf(stderr, "send_coredump_ack failed for fd %d\n", fd_coredump);
+				goto out;
+			}
+
+			fd_core_file = open_coredump_tmpfile(self->fd_tmpfs_detached);
+			if (fd_core_file < 0) {
+				fprintf(stderr, "%m - open_coredump_tmpfile failed for fd %d\n", fd_coredump);
+				goto out;
+			}
+
+			for (;;) {
+				char buffer[4096];
+				ssize_t bytes_read, bytes_write;
+
+				bytes_read = read(fd_coredump, buffer, sizeof(buffer));
+				if (bytes_read < 0) {
+					fprintf(stderr, "read failed for fd %d: %m\n", fd_coredump);
+					goto out;
+				}
+
+				if (bytes_read == 0)
+					break;
+
+				bytes_write = write(fd_core_file, buffer, bytes_read);
+				if (bytes_read != bytes_write) {
+					fprintf(stderr, "write failed for fd %d: %m\n", fd_core_file);
+					goto out;
+				}
+			}
+
+			close(fd_core_file);
+			close(fd_peer_pidfd);
+			close(fd_coredump);
+			fd_peer_pidfd = -1;
+			fd_coredump = -1;
+		}
+
+		exit_code = EXIT_SUCCESS;
+out:
+		if (fd_core_file >= 0)
+			close(fd_core_file);
+		if (fd_peer_pidfd >= 0)
+			close(fd_peer_pidfd);
+		if (fd_coredump >= 0)
+			close(fd_coredump);
+		if (fd_server >= 0)
+			close(fd_server);
+		_exit(exit_code);
+	}
+	self->pid_coredump_server = pid_coredump_server;
+
+	EXPECT_EQ(close(ipc_sockets[1]), 0);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+	for (int i = 0; i < NUM_CRASHING_COREDUMPS; i++) {
+		pid[i] = fork();
+		ASSERT_GE(pid[i], 0);
+		if (pid[i] == 0)
+			crashing_child();
+		pidfd[i] = sys_pidfd_open(pid[i], 0);
+		ASSERT_GE(pidfd[i], 0);
+	}
+
+	for (int i = 0; i < NUM_CRASHING_COREDUMPS; i++) {
+		waitpid(pid[i], &status[i], 0);
+		ASSERT_TRUE(WIFSIGNALED(status[i]));
+		ASSERT_TRUE(WCOREDUMP(status[i]));
+	}
+
+	for (int i = 0; i < NUM_CRASHING_COREDUMPS; i++) {
+		info.mask = PIDFD_INFO_EXIT | PIDFD_INFO_COREDUMP;
+		ASSERT_EQ(ioctl(pidfd[i], PIDFD_GET_INFO, &info), 0);
+		ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0);
+		ASSERT_GT((info.coredump_mask & PIDFD_COREDUMPED), 0);
+	}
+
+	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
+}
+
 TEST_HARNESS_MAIN

-- 
2.47.2