contrib/cryptsetup/lib/utils_debug.c

   1 /*
   2  * Temporary debug code to find processes locking internal cryptsetup devices.
   3  * This code is intended to run only in debug mode.
   4  *
   5  * inspired by psmisc/fuser proc scanning code
   6  */
   7 #include <stdint.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <errno.h>
  11 #include <sys/types.h>
  12 #include <sys/stat.h>
  13 #include <dirent.h>
  14 #include <fcntl.h>
  15 #include <unistd.h>
  16 #include <string.h>
  17 #include "libcryptsetup.h"
  18 #include "internal.h"
  19
  20 #define MAX_PATHNAME 1024
  21 #define MAX_SHORTNAME 64
  22
  23 static int numeric_name(const char *name)
  24 {
  25         return (name[0] < '0' || name[0] > '9') ? 0 : 1;
  26 }
  27
  28 static int check_pid(const pid_t pid, const char *dev_name, const char *short_dev_name)
  29 {
  30         char dirpath[MAX_SHORTNAME], fdpath[MAX_SHORTNAME], linkpath[MAX_PATHNAME];
  31         DIR *dirp;
  32         struct dirent *direntry;
  33         size_t len;
  34         int r = 0;
  35
  36         snprintf(dirpath, sizeof(dirpath), "/proc/%d/fd", pid);
  37
  38         if (!(dirp = opendir(dirpath)))
  39                 return r;
  40
  41         while ((direntry = readdir(dirp))) {
  42                 if (!numeric_name(direntry->d_name))
  43                         continue;
  44
  45                 snprintf(fdpath, sizeof(fdpath), "/proc/%d/fd/%s", pid, direntry->d_name);
  46
  47                 if ((len = readlink(fdpath, linkpath, MAX_PATHNAME-1)) < 0)
  48                         break;
  49                 linkpath[len] = '\0';
  50
  51                 if (!strcmp(dev_name, linkpath)) {
  52                         r = 1;
  53                         break;
  54                  }
  55
  56                 if (!strcmp(short_dev_name, linkpath)) {
  57                         r = 2;
  58                         break;
  59                  }
  60         }
  61         closedir(dirp);
  62         return r;
  63 }
  64
  65 static int read_proc_info(const pid_t pid, pid_t *ppid, char *name, int max_size)
  66 {
  67         char path[MAX_SHORTNAME], info[max_size], c;
  68         int fd, xpid, r = 0;
  69
  70         snprintf(path, sizeof(path), "/proc/%u/stat", pid);
  71         if ((fd = open(path, O_RDONLY)) < 0)
  72                 return 0;
  73
  74         if (read(fd, info, max_size) > 0 &&
  75             sscanf(info, "%d %s %c %d", &xpid, name, &c, ppid) == 4)
  76                 r = 1;
  77
  78         if (!r) {
  79                 *ppid = 0;
  80                 name[0] = '\0';
  81         }
  82         close(fd);
  83         return r;
  84 }
  85
  86 static void report_proc(const pid_t pid, const char *dev_name)
  87 {
  88         char name[MAX_PATHNAME], name2[MAX_PATHNAME];
  89         pid_t ppid, ppid2;
  90
  91         if (read_proc_info(pid, &ppid, name, MAX_PATHNAME) &&
  92             read_proc_info(ppid, &ppid2, name2, MAX_PATHNAME))
  93                 log_dbg("WARNING: Process PID %u %s [PPID %u %s] spying on internal device %s.",
  94                         pid, name, ppid, name2, dev_name);
  95 }
  96
  97 void debug_processes_using_device(const char *dm_name)
  98 {
  99         char short_dev_name[MAX_SHORTNAME], dev_name[MAX_PATHNAME];
 100         DIR *proc_dir;
 101         struct dirent *proc_dentry;
 102         struct stat st;
 103         pid_t pid;
 104
 105         if (crypt_get_debug_level() != CRYPT_LOG_DEBUG)
 106                 return;
 107
 108         snprintf(dev_name, sizeof(dev_name), "/dev/mapper/%s", dm_name);
 109         if (stat(dev_name, &st) || !S_ISBLK(st.st_mode))
 110                 return;
 111         snprintf(short_dev_name, sizeof(short_dev_name), "/dev/dm-%u", minor(st.st_rdev));
 112
 113         if (!(proc_dir = opendir("/proc")))
 114                 return;
 115
 116         while ((proc_dentry = readdir(proc_dir))) {
 117                 if (!numeric_name(proc_dentry->d_name))
 118                         continue;
 119
 120                 pid = atoi(proc_dentry->d_name);
 121                 switch(check_pid(pid, dev_name, short_dev_name)) {
 122                 case 1: report_proc(pid, dev_name);
 123                         break;
 124                 case 2: report_proc(pid, short_dev_name);
 125                 default:
 126                         break;
 127                 }
 128         }
 129         closedir(proc_dir);
 130 }