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  • Committer: Teddy Hogeborn
  • Date: 2024-11-17 16:53:00 UTC
  • Revision ID: teddy@recompile.se-20241117165300-02hxm96s8cj9528e
mandos: Avoid closing configured server network socket

If we are passed a pre-created created network socket as a file
descriptor, we must avoid later closing it (when stdin, stdout and
stderr are dup2()ed over with /dev/null) by making sure that the
network file descriptor is not 0, 1, or 2, by creating a new file
descriptor if necessary.

However, when we create a new file descriptor we must check that the
new file descriptor is not 0, 1, or 2 either, and try again until we
get a suitable file descriptor.

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Lines of Context:
plugin-runner.c
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/*
3
3
 * Mandos plugin runner - Run Mandos plugins
4
4
 *
5
 
 * Copyright © 2008-2018 Teddy Hogeborn
6
 
 * Copyright © 2008-2018 Björn Påhlsson
 
5
 * Copyright © 2008-2022 Teddy Hogeborn
 
6
 * Copyright © 2008-2022 Björn Påhlsson
7
7
 * 
8
8
 * This file is part of Mandos.
9
9
 * 
23
23
 * Contact the authors at <mandos@recompile.se>.
24
24
 */
25
25
 
26
 
#define _GNU_SOURCE             /* TEMP_FAILURE_RETRY(), getline(),
27
 
                                   O_CLOEXEC, pipe2() */
 
26
#define _GNU_SOURCE             /* strchrnul(), TEMP_FAILURE_RETRY(),
 
27
                                   getline(), asprintf(), O_CLOEXEC,
 
28
                                   scandirat(), pipe2() */
 
29
#include <argp.h>               /* argp_program_version,
 
30
                                   argp_program_bug_address,
 
31
                                   struct argp_option,
 
32
                                   struct argp_state, argp_error(),
 
33
                                   ARGP_NO_EXIT, argp_state_help,
 
34
                                   ARGP_HELP_STD_HELP,
 
35
                                   ARGP_HELP_USAGE, ARGP_HELP_EXIT_OK,
 
36
                                   ARGP_KEY_ARG, ARGP_ERR_UNKNOWN,
 
37
                                   struct argp, argp_parse(),
 
38
                                   ARGP_IN_ORDER, ARGP_NO_HELP */
 
39
#include <stdbool.h>            /* bool, false, true */
 
40
#include <sys/types.h>          /* pid_t, sig_atomic_t, uid_t, gid_t,
 
41
                                   getuid(), setgid(), setuid() */
28
42
#include <stddef.h>             /* size_t, NULL */
29
 
#include <stdlib.h>             /* malloc(), exit(), EXIT_SUCCESS,
30
 
                                   realloc() */
31
 
#include <stdbool.h>            /* bool, true, false */
32
 
#include <stdio.h>              /* fileno(), fprintf(),
33
 
                                   stderr, STDOUT_FILENO, fclose() */
34
 
#include <sys/types.h>          /* fstat(), struct stat, waitpid(),
35
 
                                   WIFEXITED(), WEXITSTATUS(), wait(),
36
 
                                   pid_t, uid_t, gid_t, getuid(),
37
 
                                   getgid() */
38
 
#include <sys/select.h>         /* fd_set, select(), FD_ZERO(),
39
 
                                   FD_SET(), FD_ISSET(), FD_CLR */
40
 
#include <sys/wait.h>           /* wait(), waitpid(), WIFEXITED(),
41
 
                                   WEXITSTATUS(), WTERMSIG() */
42
 
#include <sys/stat.h>           /* struct stat, fstat(), S_ISREG() */
43
 
#include <iso646.h>             /* and, or, not */
44
 
#include <dirent.h>             /* struct dirent, scandirat() */
45
 
#include <unistd.h>             /* fcntl(), F_GETFD, F_SETFD,
46
 
                                   FD_CLOEXEC, write(), STDOUT_FILENO,
47
 
                                   struct stat, fstat(), close(),
48
 
                                   setgid(), setuid(), S_ISREG(),
49
 
                                   faccessat() pipe2(), fork(),
50
 
                                   _exit(), dup2(), fexecve(), read()
51
 
                                */
 
43
#include <iso646.h>             /* or, and, not */
 
44
#include <string.h>             /* strcmp(), strdup(), strchrnul(),
 
45
                                   strncmp(), strlen(), strcpy(),
 
46
                                   strsep(), strchr(), strsignal() */
 
47
#include <stdlib.h>             /* malloc(), free(), reallocarray(),
 
48
                                   realloc(), EXIT_SUCCESS */
 
49
#include <errno.h>              /* errno, EINTR, ENOMEM, ECHILD,
 
50
                                   error_t, EINVAL, EMFILE, ENFILE,
 
51
                                   ENOENT, ESRCH */
 
52
#include <stdint.h>             /* SIZE_MAX */
 
53
#define _GNU_SOURCE             /* strchrnul(), TEMP_FAILURE_RETRY(),
 
54
                                   getline(), asprintf(), O_CLOEXEC,
 
55
                                   scandirat(), pipe2() */
 
56
#include <unistd.h>             /* TEMP_FAILURE_RETRY(), ssize_t,
 
57
                                   write(), STDOUT_FILENO, uid_t,
 
58
                                   gid_t, getuid(), fchown(), close(),
 
59
                                   symlink(), setgid(), setuid(),
 
60
                                   faccessat(), X_OK, pipe(), pipe2(),
 
61
                                   fork(), _exit(), dup2(), fexecve(),
 
62
                                   read(), getpass() */
52
63
#include <fcntl.h>              /* fcntl(), F_GETFD, F_SETFD,
53
 
                                   FD_CLOEXEC, openat(), scandirat(),
54
 
                                   pipe2() */
55
 
#include <string.h>             /* strsep, strlen(), strsignal(),
56
 
                                   strcmp(), strncmp() */
57
 
#include <errno.h>              /* errno */
58
 
#include <argp.h>               /* struct argp_option, struct
59
 
                                   argp_state, struct argp,
60
 
                                   argp_parse(), ARGP_ERR_UNKNOWN,
61
 
                                   ARGP_KEY_END, ARGP_KEY_ARG,
62
 
                                   error_t */
63
 
#include <signal.h>             /* struct sigaction, sigemptyset(),
64
 
                                   sigaddset(), sigaction(),
65
 
                                   sigprocmask(), SIG_BLOCK, SIGCHLD,
66
 
                                   SIG_UNBLOCK, kill(), sig_atomic_t
67
 
                                */
68
 
#include <errno.h>              /* errno, EBADF */
69
 
#include <inttypes.h>           /* intmax_t, PRIdMAX, strtoimax() */
 
64
                                   FD_CLOEXEC, open(), O_RDONLY,
 
65
                                   O_CLOEXEC, openat() */
 
66
#include <sys/wait.h>           /* waitpid(), WNOHANG, WIFEXITED(),
 
67
                                   WEXITSTATUS(), WIFSIGNALED(),
 
68
                                   WTERMSIG(), wait() */
 
69
#include <error.h>              /* error() */
 
70
#include <stdio.h>              /* FILE, fprintf(), fopen(),
 
71
                                   getline(), fclose(), EOF,
 
72
                                   asprintf(), stderr */
 
73
#include <dirent.h>             /* struct dirent, scandirat(),
 
74
                                   alphasort() */
 
75
#include <sys/stat.h>           /* struct stat, fstat(), S_ISDIR(),
 
76
                                   lstat(), S_ISREG() */
 
77
#include <sys/select.h>         /* fd_set, FD_ZERO(), FD_SETSIZE,
 
78
                                   FD_SET(), select(), FD_CLR(),
 
79
                                   FD_ISSET() */
 
80
#include <signal.h>             /* struct sigaction, SA_NOCLDSTOP,
 
81
                                   sigemptyset(), sigaddset(),
 
82
                                   SIGCHLD, sigprocmask(), SIG_BLOCK,
 
83
                                   SIG_UNBLOCK, kill(), SIGTERM */
70
84
#include <sysexits.h>           /* EX_OSERR, EX_USAGE, EX_IOERR,
71
85
                                   EX_CONFIG, EX_UNAVAILABLE, EX_OK */
72
 
#include <errno.h>              /* errno */
73
 
#include <error.h>              /* error() */
74
 
#include <fnmatch.h>            /* fnmatch() */
 
86
#include <inttypes.h>           /* intmax_t, strtoimax(), PRIdMAX */
 
87
#include <fnmatch.h>            /* fnmatch(), FNM_FILE_NAME,
 
88
                                   FNM_PERIOD, FNM_NOMATCH */
75
89
 
76
90
#define BUFFER_SIZE 256
77
91
 
179
193
  /* Resize the pointed-to array to hold one more pointer */
180
194
  char **new_array = NULL;
181
195
  do {
182
 
    new_array = realloc(*array, sizeof(char *)
183
 
                        * (size_t) ((*len) + 2));
 
196
#if defined(__GLIBC_PREREQ) and __GLIBC_PREREQ(2, 26)
 
197
    new_array = reallocarray(*array, (size_t)((*len) + 2),
 
198
                             sizeof(char *));
 
199
#else
 
200
    if(((size_t)((*len) + 2)) > (SIZE_MAX / sizeof(char *))){
 
201
      /* overflow */
 
202
      new_array = NULL;
 
203
      errno = ENOMEM;
 
204
    } else {
 
205
      new_array = realloc(*array, (size_t)((*len) + 2)
 
206
                          * sizeof(char *));
 
207
    }
 
208
#endif
184
209
  } while(new_array == NULL and errno == EINTR);
185
210
  /* Malloc check */
186
211
  if(new_array == NULL){
313
338
__attribute__((nonnull))
314
339
static void free_plugin(plugin *plugin_node){
315
340
  
 
341
  for(char **arg = (plugin_node->argv)+1; *arg != NULL; arg++){
 
342
    free(*arg);
 
343
  }
316
344
  free(plugin_node->name);
317
 
  for(char **arg = plugin_node->argv; *arg != NULL; arg++){
318
 
    free(*arg);
319
 
  }
320
345
  free(plugin_node->argv);
321
346
  for(char **env = plugin_node->environ; *env != NULL; env++){
322
347
    free(*env);
565
590
    case '?':                   /* --help */
566
591
      state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
567
592
      argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
 
593
      __builtin_unreachable();
568
594
    case -3:                    /* --usage */
569
595
      state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
570
596
      argp_state_help(state, state->out_stream,
571
597
                      ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
 
598
      __builtin_unreachable();
572
599
    case 'V':                   /* --version */
573
600
      fprintf(state->out_stream, "%s\n", argp_program_version);
574
601
      exit(EXIT_SUCCESS);
584
611
      if(arg[0] == '\0'){
585
612
        break;
586
613
      }
 
614
#if __GNUC__ >= 7
 
615
      __attribute__((fallthrough));
 
616
#else
 
617
          /* FALLTHROUGH */
 
618
#endif
587
619
    default:
588
620
      return ARGP_ERR_UNKNOWN;
589
621
    }
701
733
        
702
734
        custom_argc += 1;
703
735
        {
704
 
          char **new_argv = realloc(custom_argv, sizeof(char *)
705
 
                                    * ((size_t)custom_argc + 1));
 
736
#if defined(__GLIBC_PREREQ) and __GLIBC_PREREQ(2, 26)
 
737
          char **new_argv = reallocarray(custom_argv,
 
738
                                         (size_t)custom_argc + 1,
 
739
                                         sizeof(char *));
 
740
#else
 
741
          char **new_argv = NULL;
 
742
          if(((size_t)custom_argc + 1) > (SIZE_MAX / sizeof(char *))){
 
743
            /* overflow */
 
744
            errno = ENOMEM;
 
745
          } else {
 
746
            new_argv = realloc(custom_argv, ((size_t)custom_argc + 1)
 
747
                               * sizeof(char *));
 
748
          }
 
749
#endif
706
750
          if(new_argv == NULL){
707
 
            error(0, errno, "realloc");
 
751
            error(0, errno, "reallocarray");
708
752
            exitstatus = EX_OSERR;
709
753
            free(new_arg);
710
754
            free(org_line);
829
873
      }
830
874
      close(plugindir_fd);
831
875
    }
 
876
 
 
877
    /* Work around Debian bug #981302
 
878
       <https://bugs.debian.org/981302> */
 
879
    if(lstat("/dev/fd", &st) != 0 and errno == ENOENT){
 
880
      ret = symlink("/proc/self/fd", "/dev/fd");
 
881
      if(ret == -1){
 
882
        error(0, errno, "Failed to create /dev/fd symlink");
 
883
      }
 
884
    }
832
885
  }
833
886
  
834
887
  /* Lower permissions */
1093
1146
    
1094
1147
    new_plugin->pid = pid;
1095
1148
    new_plugin->fd = pipefd[0];
1096
 
    
 
1149
 
 
1150
    if(debug){
 
1151
      fprintf(stderr, "Plugin %s started (PID %" PRIdMAX ")\n",
 
1152
              new_plugin->name, (intmax_t) (new_plugin->pid));
 
1153
    }
 
1154
 
1097
1155
    /* Unblock SIGCHLD so signal handler can be run if this process
1098
1156
       has already completed */
1099
1157
    ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,