issue1435.go

     1  // Copyright 2019 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build linux && cgo
     6  // +build linux,cgo
     7  
     8  package cgotest
     9  
    10  import (
    11  	"fmt"
    12  	"os"
    13  	"sort"
    14  	"strings"
    15  	"syscall"
    16  	"testing"
    17  )
    18  
    19  // #include <stdio.h>
    20  // #include <stdlib.h>
    21  // #include <pthread.h>
    22  // #include <unistd.h>
    23  // #include <sys/types.h>
    24  //
    25  // pthread_t *t = NULL;
    26  // pthread_mutex_t mu;
    27  // int nts = 0;
    28  // int all_done = 0;
    29  //
    30  // static void *aFn(void *vargp) {
    31  //   int done = 0;
    32  //   while (!done) {
    33  //     usleep(100);
    34  //     pthread_mutex_lock(&mu);
    35  //     done = all_done;
    36  //     pthread_mutex_unlock(&mu);
    37  //   }
    38  //   return NULL;
    39  // }
    40  //
    41  // void trial(int argc) {
    42  //   int i;
    43  //   nts = argc;
    44  //   t = calloc(nts, sizeof(pthread_t));
    45  //   pthread_mutex_init(&mu, NULL);
    46  //   for (i = 0; i < nts; i++) {
    47  //     pthread_create(&t[i], NULL, aFn, NULL);
    48  //   }
    49  // }
    50  //
    51  // void cleanup(void) {
    52  //   int i;
    53  //   pthread_mutex_lock(&mu);
    54  //   all_done = 1;
    55  //   pthread_mutex_unlock(&mu);
    56  //   for (i = 0; i < nts; i++) {
    57  //     pthread_join(t[i], NULL);
    58  //   }
    59  //   pthread_mutex_destroy(&mu);
    60  //   free(t);
    61  // }
    62  import "C"
    63  
    64  // compareStatus is used to confirm the contents of the thread
    65  // specific status files match expectations.
    66  func compareStatus(filter, expect string) error {
    67  	expected := filter + expect
    68  	pid := syscall.Getpid()
    69  	fs, err := os.ReadDir(fmt.Sprintf("/proc/%d/task", pid))
    70  	if err != nil {
    71  		return fmt.Errorf("unable to find %d tasks: %v", pid, err)
    72  	}
    73  	expectedProc := fmt.Sprintf("Pid:\t%d", pid)
    74  	foundAThread := false
    75  	for _, f := range fs {
    76  		tf := fmt.Sprintf("/proc/%s/status", f.Name())
    77  		d, err := os.ReadFile(tf)
    78  		if err != nil {
    79  			// There are a surprising number of ways this
    80  			// can error out on linux.  We've seen all of
    81  			// the following, so treat any error here as
    82  			// equivalent to the "process is gone":
    83  			//    os.IsNotExist(err),
    84  			//    "... : no such process",
    85  			//    "... : bad file descriptor.
    86  			continue
    87  		}
    88  		lines := strings.Split(string(d), "\n")
    89  		for _, line := range lines {
    90  			// Different kernel vintages pad differently.
    91  			line = strings.TrimSpace(line)
    92  			if strings.HasPrefix(line, "Pid:\t") {
    93  				// On loaded systems, it is possible
    94  				// for a TID to be reused really
    95  				// quickly. As such, we need to
    96  				// validate that the thread status
    97  				// info we just read is a task of the
    98  				// same process PID as we are
    99  				// currently running, and not a
   100  				// recently terminated thread
   101  				// resurfaced in a different process.
   102  				if line != expectedProc {
   103  					break
   104  				}
   105  				// Fall through in the unlikely case
   106  				// that filter at some point is
   107  				// "Pid:\t".
   108  			}
   109  			if strings.HasPrefix(line, filter) {
   110  				if line == expected {
   111  					foundAThread = true
   112  					break
   113  				}
   114  				if filter == "Groups:" && strings.HasPrefix(line, "Groups:\t") {
   115  					// https://github.com/golang/go/issues/46145
   116  					// Containers don't reliably output this line in sorted order so manually sort and compare that.
   117  					a := strings.Split(line[8:], " ")
   118  					sort.Strings(a)
   119  					got := strings.Join(a, " ")
   120  					if got == expected[8:] {
   121  						foundAThread = true
   122  						break
   123  					}
   124  
   125  				}
   126  				return fmt.Errorf("%q got:%q want:%q (bad) [pid=%d file:'%s' %v]\n", tf, line, expected, pid, string(d), expectedProc)
   127  			}
   128  		}
   129  	}
   130  	if !foundAThread {
   131  		return fmt.Errorf("found no thread /proc/<TID>/status files for process %q", expectedProc)
   132  	}
   133  	return nil
   134  }
   135  
   136  // test1435 test 9 glibc implemented setuid/gid syscall functions are
   137  // mapped.  This test is a slightly more expansive test than that of
   138  // src/syscall/syscall_linux_test.go:TestSetuidEtc() insofar as it
   139  // launches concurrent threads from C code via CGo and validates that
   140  // they are subject to the system calls being tested. For the actual
   141  // Go functionality being tested here, the syscall_linux_test version
   142  // is considered authoritative, but non-trivial improvements to that
   143  // should be mirrored here.
   144  func test1435(t *testing.T) {
   145  	if syscall.Getuid() != 0 {
   146  		t.Skip("skipping root only test")
   147  	}
   148  
   149  	// Launch some threads in C.
   150  	const cts = 5
   151  	C.trial(cts)
   152  	defer C.cleanup()
   153  
   154  	vs := []struct {
   155  		call           string
   156  		fn             func() error
   157  		filter, expect string
   158  	}{
   159  		{call: "Setegid(1)", fn: func() error { return syscall.Setegid(1) }, filter: "Gid:", expect: "\t0\t1\t0\t1"},
   160  		{call: "Setegid(0)", fn: func() error { return syscall.Setegid(0) }, filter: "Gid:", expect: "\t0\t0\t0\t0"},
   161  
   162  		{call: "Seteuid(1)", fn: func() error { return syscall.Seteuid(1) }, filter: "Uid:", expect: "\t0\t1\t0\t1"},
   163  		{call: "Setuid(0)", fn: func() error { return syscall.Setuid(0) }, filter: "Uid:", expect: "\t0\t0\t0\t0"},
   164  
   165  		{call: "Setgid(1)", fn: func() error { return syscall.Setgid(1) }, filter: "Gid:", expect: "\t1\t1\t1\t1"},
   166  		{call: "Setgid(0)", fn: func() error { return syscall.Setgid(0) }, filter: "Gid:", expect: "\t0\t0\t0\t0"},
   167  
   168  		{call: "Setgroups([]int{0,1,2,3})", fn: func() error { return syscall.Setgroups([]int{0, 1, 2, 3}) }, filter: "Groups:", expect: "\t0 1 2 3"},
   169  		{call: "Setgroups(nil)", fn: func() error { return syscall.Setgroups(nil) }, filter: "Groups:", expect: ""},
   170  		{call: "Setgroups([]int{0})", fn: func() error { return syscall.Setgroups([]int{0}) }, filter: "Groups:", expect: "\t0"},
   171  
   172  		{call: "Setregid(101,0)", fn: func() error { return syscall.Setregid(101, 0) }, filter: "Gid:", expect: "\t101\t0\t0\t0"},
   173  		{call: "Setregid(0,102)", fn: func() error { return syscall.Setregid(0, 102) }, filter: "Gid:", expect: "\t0\t102\t102\t102"},
   174  		{call: "Setregid(0,0)", fn: func() error { return syscall.Setregid(0, 0) }, filter: "Gid:", expect: "\t0\t0\t0\t0"},
   175  
   176  		{call: "Setreuid(1,0)", fn: func() error { return syscall.Setreuid(1, 0) }, filter: "Uid:", expect: "\t1\t0\t0\t0"},
   177  		{call: "Setreuid(0,2)", fn: func() error { return syscall.Setreuid(0, 2) }, filter: "Uid:", expect: "\t0\t2\t2\t2"},
   178  		{call: "Setreuid(0,0)", fn: func() error { return syscall.Setreuid(0, 0) }, filter: "Uid:", expect: "\t0\t0\t0\t0"},
   179  
   180  		{call: "Setresgid(101,0,102)", fn: func() error { return syscall.Setresgid(101, 0, 102) }, filter: "Gid:", expect: "\t101\t0\t102\t0"},
   181  		{call: "Setresgid(0,102,101)", fn: func() error { return syscall.Setresgid(0, 102, 101) }, filter: "Gid:", expect: "\t0\t102\t101\t102"},
   182  		{call: "Setresgid(0,0,0)", fn: func() error { return syscall.Setresgid(0, 0, 0) }, filter: "Gid:", expect: "\t0\t0\t0\t0"},
   183  
   184  		{call: "Setresuid(1,0,2)", fn: func() error { return syscall.Setresuid(1, 0, 2) }, filter: "Uid:", expect: "\t1\t0\t2\t0"},
   185  		{call: "Setresuid(0,2,1)", fn: func() error { return syscall.Setresuid(0, 2, 1) }, filter: "Uid:", expect: "\t0\t2\t1\t2"},
   186  		{call: "Setresuid(0,0,0)", fn: func() error { return syscall.Setresuid(0, 0, 0) }, filter: "Uid:", expect: "\t0\t0\t0\t0"},
   187  	}
   188  
   189  	for i, v := range vs {
   190  		if err := v.fn(); err != nil {
   191  			t.Errorf("[%d] %q failed: %v", i, v.call, err)
   192  			continue
   193  		}
   194  		if err := compareStatus(v.filter, v.expect); err != nil {
   195  			t.Errorf("[%d] %q comparison: %v", i, v.call, err)
   196  		}
   197  	}
   198  }
   199
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