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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/testing/selftests/pidfd/pidfd_getfd_test.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/testing/selftests/pidfd/pidfd_getfd_test.c')
-rw-r--r-- | tools/testing/selftests/pidfd/pidfd_getfd_test.c | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/tools/testing/selftests/pidfd/pidfd_getfd_test.c b/tools/testing/selftests/pidfd/pidfd_getfd_test.c new file mode 100644 index 000000000..0930e2411 --- /dev/null +++ b/tools/testing/selftests/pidfd/pidfd_getfd_test.c @@ -0,0 +1,246 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define _GNU_SOURCE +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#include <linux/types.h> +#include <sched.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syscall.h> +#include <sys/prctl.h> +#include <sys/wait.h> +#include <unistd.h> +#include <sys/socket.h> +#include <linux/kcmp.h> + +#include "pidfd.h" +#include "../kselftest_harness.h" + +/* + * UNKNOWN_FD is an fd number that should never exist in the child, as it is + * used to check the negative case. + */ +#define UNKNOWN_FD 111 +#define UID_NOBODY 65535 + +static int sys_kcmp(pid_t pid1, pid_t pid2, int type, unsigned long idx1, + unsigned long idx2) +{ + return syscall(__NR_kcmp, pid1, pid2, type, idx1, idx2); +} + +static int __child(int sk, int memfd) +{ + int ret; + char buf; + + /* + * Ensure we don't leave around a bunch of orphaned children if our + * tests fail. + */ + ret = prctl(PR_SET_PDEATHSIG, SIGKILL); + if (ret) { + fprintf(stderr, "%s: Child could not set DEATHSIG\n", + strerror(errno)); + return -1; + } + + ret = send(sk, &memfd, sizeof(memfd), 0); + if (ret != sizeof(memfd)) { + fprintf(stderr, "%s: Child failed to send fd number\n", + strerror(errno)); + return -1; + } + + /* + * The fixture setup is completed at this point. The tests will run. + * + * This blocking recv enables the parent to message the child. + * Either we will read 'P' off of the sk, indicating that we need + * to disable ptrace, or we will read a 0, indicating that the other + * side has closed the sk. This occurs during fixture teardown time, + * indicating that the child should exit. + */ + while ((ret = recv(sk, &buf, sizeof(buf), 0)) > 0) { + if (buf == 'P') { + ret = prctl(PR_SET_DUMPABLE, 0); + if (ret < 0) { + fprintf(stderr, + "%s: Child failed to disable ptrace\n", + strerror(errno)); + return -1; + } + } else { + fprintf(stderr, "Child received unknown command %c\n", + buf); + return -1; + } + ret = send(sk, &buf, sizeof(buf), 0); + if (ret != 1) { + fprintf(stderr, "%s: Child failed to ack\n", + strerror(errno)); + return -1; + } + } + if (ret < 0) { + fprintf(stderr, "%s: Child failed to read from socket\n", + strerror(errno)); + return -1; + } + + return 0; +} + +static int child(int sk) +{ + int memfd, ret; + + memfd = sys_memfd_create("test", 0); + if (memfd < 0) { + fprintf(stderr, "%s: Child could not create memfd\n", + strerror(errno)); + ret = -1; + } else { + ret = __child(sk, memfd); + close(memfd); + } + + close(sk); + return ret; +} + +FIXTURE(child) +{ + /* + * remote_fd is the number of the FD which we are trying to retrieve + * from the child. + */ + int remote_fd; + /* pid points to the child which we are fetching FDs from */ + pid_t pid; + /* pidfd is the pidfd of the child */ + int pidfd; + /* + * sk is our side of the socketpair used to communicate with the child. + * When it is closed, the child will exit. + */ + int sk; +}; + +FIXTURE_SETUP(child) +{ + int ret, sk_pair[2]; + + ASSERT_EQ(0, socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sk_pair)) { + TH_LOG("%s: failed to create socketpair", strerror(errno)); + } + self->sk = sk_pair[0]; + + self->pid = fork(); + ASSERT_GE(self->pid, 0); + + if (self->pid == 0) { + close(sk_pair[0]); + if (child(sk_pair[1])) + _exit(EXIT_FAILURE); + _exit(EXIT_SUCCESS); + } + + close(sk_pair[1]); + + self->pidfd = sys_pidfd_open(self->pid, 0); + ASSERT_GE(self->pidfd, 0); + + /* + * Wait for the child to complete setup. It'll send the remote memfd's + * number when ready. + */ + ret = recv(sk_pair[0], &self->remote_fd, sizeof(self->remote_fd), 0); + ASSERT_EQ(sizeof(self->remote_fd), ret); +} + +FIXTURE_TEARDOWN(child) +{ + EXPECT_EQ(0, close(self->pidfd)); + EXPECT_EQ(0, close(self->sk)); + + EXPECT_EQ(0, wait_for_pid(self->pid)); +} + +TEST_F(child, disable_ptrace) +{ + int uid, fd; + char c; + + /* + * Turn into nobody if we're root, to avoid CAP_SYS_PTRACE + * + * The tests should run in their own process, so even this test fails, + * it shouldn't result in subsequent tests failing. + */ + uid = getuid(); + if (uid == 0) + ASSERT_EQ(0, seteuid(UID_NOBODY)); + + ASSERT_EQ(1, send(self->sk, "P", 1, 0)); + ASSERT_EQ(1, recv(self->sk, &c, 1, 0)); + + fd = sys_pidfd_getfd(self->pidfd, self->remote_fd, 0); + EXPECT_EQ(-1, fd); + EXPECT_EQ(EPERM, errno); + + if (uid == 0) + ASSERT_EQ(0, seteuid(0)); +} + +TEST_F(child, fetch_fd) +{ + int fd, ret; + + fd = sys_pidfd_getfd(self->pidfd, self->remote_fd, 0); + ASSERT_GE(fd, 0); + + ret = sys_kcmp(getpid(), self->pid, KCMP_FILE, fd, self->remote_fd); + if (ret < 0 && errno == ENOSYS) + SKIP(return, "kcmp() syscall not supported"); + EXPECT_EQ(ret, 0); + + ret = fcntl(fd, F_GETFD); + ASSERT_GE(ret, 0); + EXPECT_GE(ret & FD_CLOEXEC, 0); + + close(fd); +} + +TEST_F(child, test_unknown_fd) +{ + int fd; + + fd = sys_pidfd_getfd(self->pidfd, UNKNOWN_FD, 0); + EXPECT_EQ(-1, fd) { + TH_LOG("getfd succeeded while fetching unknown fd"); + }; + EXPECT_EQ(EBADF, errno) { + TH_LOG("%s: getfd did not get EBADF", strerror(errno)); + } +} + +TEST(flags_set) +{ + ASSERT_EQ(-1, sys_pidfd_getfd(0, 0, 1)); + EXPECT_EQ(errno, EINVAL); +} + +#if __NR_pidfd_getfd == -1 +int main(void) +{ + fprintf(stderr, "__NR_pidfd_getfd undefined. The pidfd_getfd syscall is unavailable. Test aborting\n"); + return KSFT_SKIP; +} +#else +TEST_HARNESS_MAIN +#endif |