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Commits › fcceab3
drop privileges when using libfetch
Baptiste Daroussin committed 9 years ago
commit fcceab3f1e0ae780e8a91918488aab3ba5f5ea1c
parent fe058f6
1 file changed +45 -0
modified libpkg/fetch.c
@@ -30,6 +30,7 @@
#include <sys/wait.h>

#include <sys/socket.h>

#include <sys/time.h>
+ 
#include <sys/resource.h>



#include <ctype.h>

#include <fcntl.h>
@@ -39,6 +40,8 @@
#include <fetch.h>

#include <paths.h>

#include <poll.h>
+ 
#include <pwd.h>
+ 
#include <err.h>



#include <bsd_compat.h>
@@ -469,6 +472,7 @@ pkg_fetch_file_to_fd(struct pkg_repo *repo, const char *url, int dest,
	char		*doc = NULL;

	char		 docpath[MAXPATHLEN];

	int		 retcode = EPKG_OK;
+ 
	int		 pstat;

	char		 zone[MAXHOSTNAMELEN + 13];

	struct dns_srvinfo	*srv_current = NULL;

	struct http_mirror	*http_current = NULL;
@@ -476,7 +480,10 @@ pkg_fetch_file_to_fd(struct pkg_repo *repo, const char *url, int dest,
	size_t		 buflen = 0;

	size_t		 left = 0;

	bool		 pkg_url_scheme = false;
+ 
	pid_t		 pid;

	struct sbuf	*fetchOpts = NULL;
+ 
	struct passwd	*nobody;
+ 
	struct rlimit	rl_zero;



	max_retry = pkg_object_int(pkg_config_get("FETCH_RETRY"));

	fetch_timeout = pkg_object_int(pkg_config_get("FETCH_TIMEOUT"));
@@ -528,6 +535,38 @@ pkg_fetch_file_to_fd(struct pkg_repo *repo, const char *url, int dest,
		if ((retcode = start_ssh(repo, u, &sz)) != EPKG_OK)

			goto cleanup;

		remote = repo->ssh;
+ 
	} else {
+ 
		pid = fork();
+ 
		switch (pid) {
+ 
		case -1:
+ 
			pkg_emit_error("Unable to fork");
+ 
			return (EPKG_FATAL);
+ 
		case 0:
+ 
			if (geteuid() == 0) {
+ 
				nobody = getpwnam("nobody");
+ 
				if (nobody == NULL)
+ 
					err(EXIT_FAILURE, "Enable to drop priviledges");
+ 
				if (chroot("/var/empty") == -1)
+ 
					err(EXIT_FAILURE, "Enable to chroot in /var/empty");
+ 
				chdir("/");
+ 
				setgroups(1, &nobody->pw_gid);
+ 
				setegid(nobody->pw_gid);
+ 
				setgid(nobody->pw_gid);
+ 
				seteuid(nobody->pw_uid);
+ 
				setuid(nobody->pw_uid);
+ 
			}
+ 
			rl_zero.rlim_cur = rl_zero.rlim_max = 0;
+ 
			if (setrlimit(RLIMIT_NPROC, &rl_zero) == -1)
+ 
				err(EXIT_FAILURE, "Enable to setrlimit(RLIMIT_NPROC)");
+ 
			break;
+ 
		default:
+ 
			while (waitpid(pid, &pstat, 0) == -1 && errno == EINTR)
+ 
				;
+ 
			if (WEXITSTATUS(pstat) != 0) {
+ 
				return (EPKG_FATAL);
+ 
			}
+ 
			return (EPKG_OK);
+ 
		}

	}



	doc = u->doc;
@@ -688,6 +727,12 @@ cleanup:
			fclose(remote);

	}
+ 
	if (strcmp(u->scheme, "ssh") != 0) {
+ 
		if (retcode == EPKG_OK)
+ 
			exit(0);
+ 
		exit(EXIT_FAILURE);
+ 
	}
+ 


	/* restore original doc */

	u->doc = doc;

	fetchFreeURL(u);