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// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <test_progs.h>
#include <sys/stat.h>
#include <linux/sched.h>
#include <sys/syscall.h>
#define MAX_PATH_LEN 128
#define MAX_FILES 7
#include "test_d_path.skel.h"
#include "test_d_path_check_rdonly_mem.skel.h"
#include "test_d_path_check_types.skel.h"
/* sys_close_range is not around for long time, so let's
* make sure we can call it on systems with older glibc
*/
#ifndef __NR_close_range
#ifdef __alpha__
#define __NR_close_range 546
#else
#define __NR_close_range 436
#endif
#endif
static int duration;
static struct {
__u32 cnt;
char paths[MAX_FILES][MAX_PATH_LEN];
} src;
static int set_pathname(int fd, pid_t pid)
{
char buf[MAX_PATH_LEN];
snprintf(buf, MAX_PATH_LEN, "/proc/%d/fd/%d", pid, fd);
return readlink(buf, src.paths[src.cnt++], MAX_PATH_LEN);
}
static inline long syscall_close(int fd)
{
return syscall(__NR_close_range,
(unsigned int)fd,
(unsigned int)fd,
0u);
}
static int trigger_fstat_events(pid_t pid)
{
int sockfd = -1, procfd = -1, devfd = -1;
int localfd = -1, indicatorfd = -1;
int pipefd[2] = { -1, -1 };
struct stat fileStat;
int ret = -1;
/* unmountable pseudo-filesystems */
if (CHECK(pipe(pipefd) < 0, "trigger", "pipe failed\n"))
return ret;
/* unmountable pseudo-filesystems */
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (CHECK(sockfd < 0, "trigger", "socket failed\n"))
goto out_close;
/* mountable pseudo-filesystems */
procfd = open("/proc/self/comm", O_RDONLY);
if (CHECK(procfd < 0, "trigger", "open /proc/self/comm failed\n"))
goto out_close;
devfd = open("/dev/urandom", O_RDONLY);
if (CHECK(devfd < 0, "trigger", "open /dev/urandom failed\n"))
goto out_close;
localfd = open("/tmp/d_path_loadgen.txt", O_CREAT | O_RDONLY, 0644);
if (CHECK(localfd < 0, "trigger", "open /tmp/d_path_loadgen.txt failed\n"))
goto out_close;
/* bpf_d_path will return path with (deleted) */
remove("/tmp/d_path_loadgen.txt");
indicatorfd = open("/tmp/", O_PATH);
if (CHECK(indicatorfd < 0, "trigger", "open /tmp/ failed\n"))
goto out_close;
ret = set_pathname(pipefd[0], pid);
if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[0]\n"))
goto out_close;
ret = set_pathname(pipefd[1], pid);
if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[1]\n"))
goto out_close;
ret = set_pathname(sockfd, pid);
if (CHECK(ret < 0, "trigger", "set_pathname failed for socket\n"))
goto out_close;
ret = set_pathname(procfd, pid);
if (CHECK(ret < 0, "trigger", "set_pathname failed for proc\n"))
goto out_close;
ret = set_pathname(devfd, pid);
if (CHECK(ret < 0, "trigger", "set_pathname failed for dev\n"))
goto out_close;
ret = set_pathname(localfd, pid);
if (CHECK(ret < 0, "trigger", "set_pathname failed for file\n"))
goto out_close;
ret = set_pathname(indicatorfd, pid);
if (CHECK(ret < 0, "trigger", "set_pathname failed for dir\n"))
goto out_close;
/* triggers vfs_getattr */
fstat(pipefd[0], &fileStat);
fstat(pipefd[1], &fileStat);
fstat(sockfd, &fileStat);
fstat(procfd, &fileStat);
fstat(devfd, &fileStat);
fstat(localfd, &fileStat);
fstat(indicatorfd, &fileStat);
out_close:
/* sys_close no longer triggers filp_close, but we can
* call sys_close_range instead which still does
*/
syscall_close(pipefd[0]);
syscall_close(pipefd[1]);
syscall_close(sockfd);
syscall_close(procfd);
syscall_close(devfd);
syscall_close(localfd);
syscall_close(indicatorfd);
return ret;
}
static void attach_and_load(struct test_d_path **skel)
{
int err;
*skel = test_d_path__open_and_load();
if (CHECK(!*skel, "setup", "d_path skeleton failed\n"))
goto cleanup;
err = test_d_path__attach(*skel);
if (CHECK(err, "setup", "attach failed: %d\n", err))
goto cleanup;
(*skel)->bss->my_pid = getpid();
return;
cleanup:
test_d_path__destroy(*skel);
*skel = NULL;
}
static void test_d_path_basic(void)
{
struct test_d_path__bss *bss;
struct test_d_path *skel;
int err;
attach_and_load(&skel);
if (!skel)
goto cleanup;
bss = skel->bss;
err = trigger_fstat_events(bss->my_pid);
if (err < 0)
goto cleanup;
if (CHECK(!bss->called_stat,
"stat",
"trampoline for security_inode_getattr was not called\n"))
goto cleanup;
if (CHECK(!bss->called_close,
"close",
"trampoline for filp_close was not called\n"))
goto cleanup;
for (int i = 0; i < MAX_FILES; i++) {
CHECK(strncmp(src.paths[i], bss->paths_stat[i], MAX_PATH_LEN),
"check",
"failed to get stat path[%d]: %s vs %s\n",
i, src.paths[i], bss->paths_stat[i]);
CHECK(strncmp(src.paths[i], bss->paths_close[i], MAX_PATH_LEN),
"check",
"failed to get close path[%d]: %s vs %s\n",
i, src.paths[i], bss->paths_close[i]);
/* The d_path helper returns size plus NUL char, hence + 1 */
CHECK(bss->rets_stat[i] != strlen(bss->paths_stat[i]) + 1,
"check",
"failed to match stat return [%d]: %d vs %zd [%s]\n",
i, bss->rets_stat[i], strlen(bss->paths_stat[i]) + 1,
bss->paths_stat[i]);
CHECK(bss->rets_close[i] != strlen(bss->paths_stat[i]) + 1,
"check",
"failed to match stat return [%d]: %d vs %zd [%s]\n",
i, bss->rets_close[i], strlen(bss->paths_close[i]) + 1,
bss->paths_stat[i]);
}
cleanup:
test_d_path__destroy(skel);
}
static void test_d_path_check_rdonly_mem(void)
{
struct test_d_path_check_rdonly_mem *skel;
skel = test_d_path_check_rdonly_mem__open_and_load();
ASSERT_ERR_PTR(skel, "unexpected_load_overwriting_rdonly_mem");
test_d_path_check_rdonly_mem__destroy(skel);
}
static void test_d_path_check_types(void)
{
struct test_d_path_check_types *skel;
skel = test_d_path_check_types__open_and_load();
ASSERT_ERR_PTR(skel, "unexpected_load_passing_wrong_type");
test_d_path_check_types__destroy(skel);
}
/* Check if the verifier correctly generates code for
* accessing the memory modified by d_path helper.
*/
static void test_d_path_mem_access(void)
{
int localfd = -1;
char path_template[] = "/dev/shm/d_path_loadgen.XXXXXX";
struct test_d_path__bss *bss;
struct test_d_path *skel;
attach_and_load(&skel);
if (!skel)
goto cleanup;
bss = skel->bss;
localfd = mkstemp(path_template);
if (CHECK(localfd < 0, "trigger", "mkstemp failed\n"))
goto cleanup;
if (CHECK(fallocate(localfd, 0, 0, 1024) < 0, "trigger", "fallocate failed\n"))
goto cleanup;
remove(path_template);
if (CHECK(!bss->path_match_fallocate, "check",
"failed to read fallocate path"))
goto cleanup;
cleanup:
syscall_close(localfd);
test_d_path__destroy(skel);
}
void test_d_path(void)
{
if (test__start_subtest("basic"))
test_d_path_basic();
if (test__start_subtest("check_rdonly_mem"))
test_d_path_check_rdonly_mem();
if (test__start_subtest("check_alloc_mem"))
test_d_path_check_types();
if (test__start_subtest("check_mem_access"))
test_d_path_mem_access();
}
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