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      1 /*
      2  * pscap.c - A program that lists running processes with capabilities
      3  * Copyright (c) 2009,2012 Red Hat Inc., Durham, North Carolina.
      4  * All Rights Reserved.
      5  *
      6  * This software may be freely redistributed and/or modified under the
      7  * terms of the GNU General Public License as published by the Free
      8  * Software Foundation; either version 2, or (at your option) any
      9  * later version.
     10  *
     11  * This program is distributed in the hope that it will be useful,
     12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     14  * GNU General Public License for more details.
     15  *
     16  * You should have received a copy of the GNU General Public License
     17  * along with this program; see the file COPYING. If not, write to the
     18  * Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
     19  *
     20  * Authors:
     21  *   Steve Grubb <sgrubb (at) redhat.com>
     22  */
     23 
     24 #include "config.h"
     25 #include <stdio.h>
     26 #include <stdio_ext.h>
     27 #include <unistd.h>
     28 #include <stdlib.h>
     29 #include <errno.h>
     30 #include <string.h>
     31 #include <dirent.h>
     32 #include <fcntl.h>
     33 #include <pwd.h>
     34 #include "cap-ng.h"
     35 
     36 
     37 static void usage(void)
     38 {
     39 	fprintf(stderr, "usage: pscap [-a]\n");
     40 	exit(1);
     41 }
     42 
     43 int main(int argc, char *argv[])
     44 {
     45 	DIR *d;
     46 	struct dirent *ent;
     47 	int header = 0, show_all = 0, caps;
     48 	pid_t our_pid = getpid();
     49 
     50 	if (argc > 2) {
     51 		fputs("Too many arguments\n", stderr);
     52 		usage();
     53 	}
     54 	if (argc == 2) {
     55 		if (strcmp(argv[1], "-a") == 0)
     56 			show_all = 1;
     57 		else
     58 			usage();
     59 	}
     60 
     61 	d = opendir("/proc");
     62 	if (d == NULL) {
     63 		printf("Can't open /proc: %s\n", strerror(errno));
     64 		return 1;
     65 	}
     66 	while (( ent = readdir(d) )) {
     67 		int pid, ppid, uid = -1, euid = -1;
     68 		char buf[100];
     69 		char *tmp, cmd[16], state, *name = NULL;
     70 		int fd, len;
     71 		struct passwd *p;
     72 
     73 		// Skip non-process dir entries
     74 		if(*ent->d_name<'0' || *ent->d_name>'9')
     75 			continue;
     76 		errno = 0;
     77 		pid = strtol(ent->d_name, NULL, 10);
     78 		if (errno)
     79 			continue;
     80 
     81 		/* Skip our pid so we aren't listed */
     82 		if (pid == our_pid)
     83 			continue;
     84 
     85 		// Parse up the stat file for the proc
     86 		snprintf(buf, 32, "/proc/%d/stat", pid);
     87 		fd = open(buf, O_RDONLY|O_CLOEXEC, 0);
     88 		if (fd < 0)
     89 			continue;
     90 		len = read(fd, buf, sizeof buf - 1);
     91 		close(fd);
     92 		if (len < 40)
     93 			continue;
     94 		buf[len] = 0;
     95 		tmp = strrchr(buf, ')');
     96 		if (tmp)
     97 			*tmp = 0;
     98 		else
     99 			continue;
    100 		memset(cmd, 0, sizeof(cmd));
    101 		sscanf(buf, "%d (%15c", &ppid, cmd);
    102 		sscanf(tmp+2, "%c %d", &state, &ppid);
    103 
    104 		// Skip kthreads
    105 		if (pid == 2 || ppid == 2)
    106 			continue;
    107 
    108 		if (!show_all && pid == 1)
    109 			continue;
    110 
    111 		// now get the capabilities
    112 		capng_clear(CAPNG_SELECT_BOTH);
    113 		capng_setpid(pid);
    114 		if (capng_get_caps_process())
    115 			continue;
    116 
    117 		// And print out anything with capabilities
    118 		caps = capng_have_capabilities(CAPNG_SELECT_CAPS);
    119 		if (caps > CAPNG_NONE) {
    120 			// Get the effective uid
    121 			FILE *f;
    122 			int line;
    123 			snprintf(buf, 32, "/proc/%d/status", pid);
    124 			f = fopen(buf, "rte");
    125 			if (f == NULL)
    126 				euid = 0;
    127 			else {
    128 				line = 0;
    129 				__fsetlocking(f, FSETLOCKING_BYCALLER);
    130 				while (fgets(buf, sizeof(buf), f)) {
    131 					if (line == 0) {
    132 						line++;
    133 						continue;
    134 					}
    135 					if (memcmp(buf, "Uid:", 4) == 0) {
    136 						int id;
    137 						sscanf(buf, "Uid: %d %d",
    138 							&id, &euid);
    139 						break;
    140 					}
    141 				}
    142 				fclose(f);
    143 			}
    144 
    145 			len = read(fd, buf, sizeof buf - 1);
    146 			close(fd);
    147 			if (header == 0) {
    148 				printf("%-5s %-5s %-10s  %-16s  %s\n",
    149 				    "ppid", "pid", "name", "command",
    150 				    "capabilities");
    151 				header = 1;
    152 			}
    153 			if (euid == 0) {
    154 				// Take short cut for this one
    155 				name = "root";
    156 				uid = 0;
    157 			} else if (euid != uid) {
    158 				// Only look up if name changed
    159 				p = getpwuid(euid);
    160 				uid = euid;
    161 				if (p)
    162 					name = p->pw_name;
    163 				// If not taking this branch, use last val
    164 			}
    165 			if (name) {
    166 				printf("%-5d %-5d %-10s  %-16s  ", ppid, pid,
    167 					name, cmd);
    168 			} else
    169 				printf("%-5d %-5d %-10d  %-16s  ", ppid, pid,
    170 					uid, cmd);
    171 			if (caps == CAPNG_PARTIAL) {
    172 				capng_print_caps_text(CAPNG_PRINT_STDOUT,
    173 							CAPNG_PERMITTED);
    174 				if (capng_have_capabilities(CAPNG_SELECT_BOUNDS)
    175 							 == CAPNG_FULL)
    176 					printf(" +");
    177 				printf("\n");
    178 			} else
    179 				printf("full\n");
    180 		}
    181 	}
    182 	closedir(d);
    183 	return 0;
    184 }
    185 
    186