Extend SCM_PIDFD test scenarios to also cover dead task's
pidfd retrieval and reading its exit info.
Cc: linux-kselft...@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: net...@vger.kernel.org
Cc: Shuah Khan <sh...@kernel.org>
Cc: "David S. Miller" <da...@davemloft.net>
Cc: Eric Dumazet <eduma...@google.com>
Cc: Jakub Kicinski <k...@kernel.org>
Cc: Paolo Abeni <pab...@redhat.com>
Cc: Simon Horman <ho...@kernel.org>
Cc: Christian Brauner <brau...@kernel.org>
Cc: Kuniyuki Iwashima <kun...@google.com>
Cc: Lennart Poettering <mzxre...@0pointer.de>
Cc: Luca Boccassi <bl...@debian.org>
Cc: David Rheinsberg <da...@readahead.eu>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalit...@canonical.com>
---
.../testing/selftests/net/af_unix/scm_pidfd.c | 217 ++++++++++++++----
1 file changed, 173 insertions(+), 44 deletions(-)
diff --git a/tools/testing/selftests/net/af_unix/scm_pidfd.c
b/tools/testing/selftests/net/af_unix/scm_pidfd.c
index 7e534594167e..37e034874034 100644
--- a/tools/testing/selftests/net/af_unix/scm_pidfd.c
+++ b/tools/testing/selftests/net/af_unix/scm_pidfd.c
@@ -15,6 +15,7 @@
#include <sys/types.h>
#include <sys/wait.h>
+#include "../../pidfd/pidfd.h"
#include "../../kselftest_harness.h"
#define clean_errno() (errno == 0 ? "None" : strerror(errno))
@@ -26,6 +27,8 @@
#define SCM_PIDFD 0x04
#endif
+#define CHILD_EXIT_CODE_OK 123
+
static void child_die()
{
exit(1);
@@ -126,16 +129,65 @@ static pid_t get_pid_from_fdinfo_file(int pidfd, const
char *key, size_t keylen)
return result;
}
+struct cmsg_data {
+ struct ucred *ucred;
+ int *pidfd;
+};
+
+static int parse_cmsg(struct msghdr *msg, struct cmsg_data *res)
+{
+ struct cmsghdr *cmsg;
+ int data = 0;
+
+ 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(*res->pidfd)) {
+ log_err("CMSG parse: SCM_PIDFD wrong len");
+ return 1;
+ }
+
+ res->pidfd = (void *)CMSG_DATA(cmsg);
+ }
+
+ if (cmsg->cmsg_level == SOL_SOCKET &&
+ cmsg->cmsg_type == SCM_CREDENTIALS) {
+ if (cmsg->cmsg_len < sizeof(*res->ucred)) {
+ log_err("CMSG parse: SCM_CREDENTIALS wrong
len");
+ return 1;
+ }
+
+ res->ucred = (void *)CMSG_DATA(cmsg);
+ }
+ }
+
+ if (!res->pidfd) {
+ log_err("CMSG parse: SCM_PIDFD not found");
+ return 1;
+ }
+
+ if (!res->ucred) {
+ log_err("CMSG parse: SCM_CREDENTIALS not found");
+ return 1;
+ }
+
+ return 0;
+}
+
static int cmsg_check(int fd)
{
struct msghdr msg = { 0 };
- struct cmsghdr *cmsg;
+ struct cmsg_data res;
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;
@@ -158,53 +210,99 @@ static int cmsg_check(int fd)
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;
- }
+ /* send(pfd, "x", sizeof(char), 0) */
+ if (data != 'x') {
+ log_err("recvmsg: data corruption");
+ return 1;
+ }
- pidfd = (void *)CMSG_DATA(cmsg);
- }
+ if (parse_cmsg(&msg, &res)) {
+ log_err("CMSG parse: parse_cmsg() failed");
+ return 1;
+ }
- 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;
- }
+ /* pidfd from SCM_PIDFD should point to the parent process PID */
+ parent_pid =
+ get_pid_from_fdinfo_file(*res.pidfd, "Pid:", sizeof("Pid:") -
1);
+ if (parent_pid != getppid()) {
+ log_err("wrong SCM_PIDFD %d != %d", parent_pid, getppid());
+ close(*res.pidfd);
+ return 1;
+ }
- ucred = (void *)CMSG_DATA(cmsg);
- }
+ close(*res.pidfd);
+ return 0;
+}
+
+static int cmsg_check_dead(int fd, int expected_pid)
+{
+ int err;
+ struct msghdr msg = { 0 };
+ struct cmsg_data res;
+ struct iovec iov;
+ int data = 0;
+ char control[CMSG_SPACE(sizeof(struct ucred)) +
+ CMSG_SPACE(sizeof(int))] = { 0 };
+ pid_t client_pid;
+ struct pidfd_info info = {
+ .mask = PIDFD_INFO_EXIT,
+ };
+
+ 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;
}
- /* send(pfd, "x", sizeof(char), 0) */
- if (data != 'x') {
+ if (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC)) {
+ log_err("recvmsg: truncated");
+ return 1;
+ }
+
+ /* send(cfd, "y", sizeof(char), 0) */
+ if (data != 'y') {
log_err("recvmsg: data corruption");
return 1;
}
- if (!pidfd) {
- log_err("CMSG parse: SCM_PIDFD not found");
+ if (parse_cmsg(&msg, &res)) {
+ log_err("CMSG parse: parse_cmsg() failed");
return 1;
}
- if (!ucred) {
- log_err("CMSG parse: SCM_CREDENTIALS not found");
+ /*
+ * pidfd from SCM_PIDFD should point to the client_pid.
+ * Let's read exit information and check if it's what
+ * we expect to see.
+ */
+ if (ioctl(*res.pidfd, PIDFD_GET_INFO, &info)) {
+ log_err("%s: ioctl(PIDFD_GET_INFO) failed", __func__);
+ close(*res.pidfd);
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());
+ if (!(info.mask & PIDFD_INFO_EXIT)) {
+ log_err("%s: No exit information from ioctl(PIDFD_GET_INFO)",
__func__);
+ close(*res.pidfd);
return 1;
}
+ err = WIFEXITED(info.exit_code) ? WEXITSTATUS(info.exit_code) : 1;
+ if (err != CHILD_EXIT_CODE_OK) {
+ log_err("%s: wrong exit_code %d != %d", __func__, err,
CHILD_EXIT_CODE_OK);
+ close(*res.pidfd);
+ return 1;
+ }
+
+ close(*res.pidfd);
return 0;
}
@@ -291,6 +389,24 @@ static void fill_sockaddr(struct sock_addr *addr, bool
abstract)
memcpy(sun_path_buf, addr->sock_name, strlen(addr->sock_name));
}
+static int sk_enable_cred_pass(int sk)
+{
+ int on = 0;
+
+ on = 1;
+ if (setsockopt(sk, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on))) {
+ log_err("Failed to set SO_PASSCRED");
+ return 1;
+ }
+
+ if (setsockopt(sk, SOL_SOCKET, SO_PASSPIDFD, &on, sizeof(on))) {
+ log_err("Failed to set SO_PASSPIDFD");
+ return 1;
+ }
+
+ return 0;
+}
+
static void client(FIXTURE_DATA(scm_pidfd) *self,
const FIXTURE_VARIANT(scm_pidfd) *variant)
{
@@ -299,7 +415,6 @@ static void client(FIXTURE_DATA(scm_pidfd) *self,
struct ucred peer_cred;
int peer_pidfd;
pid_t peer_pid;
- int on = 0;
cfd = socket(AF_UNIX, variant->type, 0);
if (cfd < 0) {
@@ -322,14 +437,8 @@ static void client(FIXTURE_DATA(scm_pidfd) *self,
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");
+ if (sk_enable_cred_pass(cfd)) {
+ log_err("sk_enable_cred_pass() failed");
child_die();
}
@@ -340,6 +449,12 @@ static void client(FIXTURE_DATA(scm_pidfd) *self,
child_die();
}
+ /* send something to the parent so it can receive SCM_PIDFD too and
validate it */
+ if (send(cfd, "y", sizeof(char), 0) == -1) {
+ log_err("Failed to send(cfd, \"y\", sizeof(char), 0)");
+ child_die();
+ }
+
/* skip further for SOCK_DGRAM as it's not applicable */
if (variant->type == SOCK_DGRAM)
return;
@@ -398,7 +513,13 @@ TEST_F(scm_pidfd, test)
close(self->server);
close(self->startup_pipe[0]);
client(self, variant);
- exit(0);
+
+ /*
+ * It's a bit unusual, but in case of success we return non-zero
+ * exit code (CHILD_EXIT_CODE_OK) and then we expect to read it
+ * from ioctl(PIDFD_GET_INFO) in cmsg_check_dead().
+ */
+ exit(CHILD_EXIT_CODE_OK);
}
close(self->startup_pipe[1]);
@@ -421,9 +542,17 @@ TEST_F(scm_pidfd, test)
ASSERT_NE(-1, err);
}
- close(pfd);
waitpid(self->client_pid, &child_status, 0);
- ASSERT_EQ(0, WIFEXITED(child_status) ? WEXITSTATUS(child_status) : 1);
+ /* see comment before exit(CHILD_EXIT_CODE_OK) */
+ ASSERT_EQ(CHILD_EXIT_CODE_OK, WIFEXITED(child_status) ?
WEXITSTATUS(child_status) : 1);
+
+ err = sk_enable_cred_pass(pfd);
+ ASSERT_EQ(0, err);
+
+ err = cmsg_check_dead(pfd, self->client_pid);
+ ASSERT_EQ(0, err);
+
+ close(pfd);
}
TEST_HARNESS_MAIN
--
2.43.0
