safe-mkstemp.c revision 033e315cc9396332a09b98bee7824b8e6641c2fc
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen/* Copyright (c) 2007-2016 Dovecot authors, see the included COPYING file */
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen#include "lib.h"
345648b341f228bd7f0b89f8aa3ecb9c470d817eTimo Sirainen#include "str.h"
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen#include "hex-binary.h"
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen#include "randgen.h"
5a2cb3d097a2d9a9e930af997e7bf3400a8d840dTimo Sirainen#include "hostpid.h"
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen#include "eacces-error.h"
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen#include "safe-mkstemp.h"
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen#include <unistd.h>
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen#include <fcntl.h>
16f46efe0e090fe6975acf012a61a160f4787985Andrey Panin#include <sys/stat.h>
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainenstatic int ATTR_NULL(5)
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainensafe_mkstemp_full(string_t *prefix, mode_t mode, uid_t uid, gid_t gid,
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen const char *gid_origin)
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen{
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen size_t prefix_len;
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen struct stat st;
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen unsigned char randbuf[8];
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen mode_t old_umask;
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen int fd;
16f46efe0e090fe6975acf012a61a160f4787985Andrey Panin
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen prefix_len = str_len(prefix);
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen for (;;) {
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen do {
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen random_fill_weak(randbuf, sizeof(randbuf));
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen str_truncate(prefix, prefix_len);
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen str_append(prefix,
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen binary_to_hex(randbuf, sizeof(randbuf)));
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen } while (lstat(str_c(prefix), &st) == 0);
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen if (errno != ENOENT) {
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen i_error("stat(%s) failed: %m", str_c(prefix));
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen str_truncate(prefix, prefix_len);
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen return -1;
7242e1ce7803b83bc82e239ef111b47c1c72dd4bAndrey Panin }
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen old_umask = umask(0666 ^ mode);
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen fd = open(str_c(prefix), O_RDWR | O_EXCL | O_CREAT, 0666);
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen umask(old_umask);
c57776c06ec99ba9b0dafdbf9475ea72ea8ca134Timo Sirainen if (fd != -1)
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen break;
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen if (errno != EEXIST) {
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen if (errno != ENOENT && errno != EACCES)
d1414c09cf0d58ac983054e2f4e1a1f329272dcfTimo Sirainen i_error("open(%s) failed: %m", str_c(prefix));
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen str_truncate(prefix, prefix_len);
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen return -1;
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen }
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen }
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen if (uid == (uid_t)-1 && gid == (gid_t)-1)
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen return fd;
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen if (fchown(fd, uid, gid) < 0) {
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen if (errno == EPERM) {
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen i_error("%s", eperm_error_get_chgrp("fchown",
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen str_c(prefix), gid, gid_origin));
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen } else {
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen i_error("fchown(%s, %ld, %ld) failed: %m",
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen str_c(prefix),
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen uid == (uid_t)-1 ? -1L : (long)uid,
e70d5895795732b8247ab9abb045b438e954bc46Timo Sirainen gid == (gid_t)-1 ? -1L : (long)gid);
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen }
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen i_close_fd(&fd);
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen i_unlink(str_c(prefix));
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen str_truncate(prefix, prefix_len);
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen return -1;
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen }
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen return fd;
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen}
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainenint safe_mkstemp(string_t *prefix, mode_t mode, uid_t uid, gid_t gid)
0469ed17dafcc56589ce00960a23f4f06817dfb5Timo Sirainen{
1ddec6312bc6882aeb17d4d46d19cbca1723b68bTimo Sirainen return safe_mkstemp_full(prefix, mode, uid, gid, NULL);
0469ed17dafcc56589ce00960a23f4f06817dfb5Timo Sirainen}
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainenint safe_mkstemp_group(string_t *prefix, mode_t mode,
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen gid_t gid, const char *gid_origin)
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen{
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen return safe_mkstemp_full(prefix, mode, (uid_t)-1, gid, gid_origin);
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen}
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainenint safe_mkstemp_hostpid(string_t *prefix, mode_t mode, uid_t uid, gid_t gid)
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen{
e9e2d23e1ea5a149a7d8828d2a45b9f2313c3785Timo Sirainen size_t orig_prefix_len = str_len(prefix);
e9e2d23e1ea5a149a7d8828d2a45b9f2313c3785Timo Sirainen int fd;
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen
97c339398f1aba6f315b55a9b6ee6b020e33bea4Timo Sirainen str_printfa(prefix, "%s.%s.", my_hostname, my_pid);
0469ed17dafcc56589ce00960a23f4f06817dfb5Timo Sirainen if ((fd = safe_mkstemp(prefix, mode, uid, gid)) == -1)
0469ed17dafcc56589ce00960a23f4f06817dfb5Timo Sirainen str_truncate(prefix, orig_prefix_len);
0469ed17dafcc56589ce00960a23f4f06817dfb5Timo Sirainen return fd;
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen}
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainenint safe_mkstemp_hostpid_group(string_t *prefix, mode_t mode,
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen gid_t gid, const char *gid_origin)
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen{
33c6d5807b449463e9b81db5ec99fe027cc1b984Timo Sirainen size_t orig_prefix_len = str_len(prefix);
8eea67470c1bd8562a62e7445d930bb2079b1a43Timo Sirainen int fd;
94a78eb438622fa53abef1e1726714dacad4b61cTimo Sirainen
25757faf029c369a8318349dafe952e2358df1d8Timo Sirainen str_printfa(prefix, "%s.%s.", my_hostname, my_pid);
c7480644202e5451fbed448508ea29a25cffc99cTimo Sirainen if ((fd = safe_mkstemp_group(prefix, mode, gid, gid_origin)) == -1)
e9e2d23e1ea5a149a7d8828d2a45b9f2313c3785Timo Sirainen str_truncate(prefix, orig_prefix_len);
e9e2d23e1ea5a149a7d8828d2a45b9f2313c3785Timo Sirainen return fd;
a4ac325c2802693c6b761e5a8fda961e5d7490eaTimo Sirainen}
b7c2065b3f10f9ae27787a9db5aaefbfc70d4502Timo Sirainen