Files
rsync/syscall.c
Silent 77be09aaed syscall: fix a Y2038 bug by replacing Int32x32To64 with multiplication
Int32x32To64 macro internally truncates the arguments to int32,
while time_t is 64-bit on most/all modern platforms.
Therefore, usage of this macro creates a Year 2038 bug.
2025-08-23 17:32:11 +10:00

816 lines
18 KiB
C

/*
* Syscall wrappers to ensure that nothing gets done in dry_run mode
* and to handle system peculiarities.
*
* Copyright (C) 1998 Andrew Tridgell
* Copyright (C) 2002 Martin Pool
* Copyright (C) 2003-2022 Wayne Davison
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, visit the http://fsf.org website.
*/
#include "rsync.h"
#if !defined MKNOD_CREATES_SOCKETS && defined HAVE_SYS_UN_H
#include <sys/un.h>
#endif
#ifdef HAVE_SYS_ATTR_H
#include <sys/attr.h>
#endif
#if defined HAVE_SYS_FALLOCATE && !defined HAVE_FALLOCATE
#include <sys/syscall.h>
#endif
#include "ifuncs.h"
extern int dry_run;
extern int am_root;
extern int am_sender;
extern int read_only;
extern int list_only;
extern int inplace;
extern int preallocate_files;
extern int preserve_perms;
extern int preserve_executability;
extern int open_noatime;
extern int copy_links;
extern int copy_unsafe_links;
#ifndef S_BLKSIZE
# if defined hpux || defined __hpux__ || defined __hpux
# define S_BLKSIZE 1024
# elif defined _AIX && defined _I386
# define S_BLKSIZE 4096
# else
# define S_BLKSIZE 512
# endif
#endif
#ifdef SUPPORT_CRTIMES
#ifdef HAVE_GETATTRLIST
#pragma pack(push, 4)
struct create_time {
uint32 length;
struct timespec crtime;
};
#pragma pack(pop)
#elif defined __CYGWIN__
#include <windows.h>
#endif
#endif
#define RETURN_ERROR_IF(x,e) \
do { \
if (x) { \
errno = (e); \
return -1; \
} \
} while (0)
#define RETURN_ERROR_IF_RO_OR_LO RETURN_ERROR_IF(read_only || list_only, EROFS)
int do_unlink(const char *path)
{
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
return unlink(path);
}
#ifdef SUPPORT_LINKS
int do_symlink(const char *lnk, const char *path)
{
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
#if defined NO_SYMLINK_XATTRS || defined NO_SYMLINK_USER_XATTRS
/* For --fake-super, we create a normal file with mode 0600
* and write the lnk into it. */
if (am_root < 0) {
int ok, len = strlen(lnk);
int fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, S_IWUSR|S_IRUSR);
if (fd < 0)
return -1;
ok = write(fd, lnk, len) == len;
if (close(fd) < 0)
ok = 0;
return ok ? 0 : -1;
}
#endif
return symlink(lnk, path);
}
#if defined NO_SYMLINK_XATTRS || defined NO_SYMLINK_USER_XATTRS
ssize_t do_readlink(const char *path, char *buf, size_t bufsiz)
{
/* For --fake-super, we read the link from the file. */
if (am_root < 0) {
int fd = do_open_nofollow(path, O_RDONLY);
if (fd >= 0) {
int len = read(fd, buf, bufsiz);
close(fd);
return len;
}
if (errno != ELOOP)
return -1;
/* A real symlink needs to be turned into a fake one on the receiving
* side, so tell the generator that the link has no length. */
if (!am_sender)
return 0;
/* Otherwise fall through and let the sender report the real length. */
}
return readlink(path, buf, bufsiz);
}
#endif
#endif
#if defined HAVE_LINK || defined HAVE_LINKAT
int do_link(const char *old_path, const char *new_path)
{
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
#ifdef HAVE_LINKAT
return linkat(AT_FDCWD, old_path, AT_FDCWD, new_path, 0);
#else
return link(old_path, new_path);
#endif
}
#endif
int do_lchown(const char *path, uid_t owner, gid_t group)
{
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
#ifndef HAVE_LCHOWN
#define lchown chown
#endif
return lchown(path, owner, group);
}
int do_mknod(const char *pathname, mode_t mode, dev_t dev)
{
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
/* For --fake-super, we create a normal file with mode 0600. */
if (am_root < 0) {
int fd = open(pathname, O_WRONLY|O_CREAT|O_TRUNC, S_IWUSR|S_IRUSR);
if (fd < 0 || close(fd) < 0)
return -1;
return 0;
}
#if !defined MKNOD_CREATES_FIFOS && defined HAVE_MKFIFO
if (S_ISFIFO(mode))
return mkfifo(pathname, mode);
#endif
#if !defined MKNOD_CREATES_SOCKETS && defined HAVE_SYS_UN_H
if (S_ISSOCK(mode)) {
int sock;
struct sockaddr_un saddr;
unsigned int len = strlcpy(saddr.sun_path, pathname, sizeof saddr.sun_path);
if (len >= sizeof saddr.sun_path) {
errno = ENAMETOOLONG;
return -1;
}
#ifdef HAVE_SOCKADDR_UN_LEN
saddr.sun_len = len + 1;
#endif
saddr.sun_family = AF_UNIX;
if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0
|| (unlink(pathname) < 0 && errno != ENOENT)
|| (bind(sock, (struct sockaddr*)&saddr, sizeof saddr)) < 0)
return -1;
close(sock);
#ifdef HAVE_CHMOD
return do_chmod(pathname, mode);
#else
return 0;
#endif
}
#endif
#ifdef HAVE_MKNOD
return mknod(pathname, mode, dev);
#else
return -1;
#endif
}
int do_rmdir(const char *pathname)
{
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
return rmdir(pathname);
}
int do_open(const char *pathname, int flags, mode_t mode)
{
if (flags != O_RDONLY) {
RETURN_ERROR_IF(dry_run, 0);
RETURN_ERROR_IF_RO_OR_LO;
}
#ifdef O_NOATIME
if (open_noatime)
flags |= O_NOATIME;
#endif
return open(pathname, flags | O_BINARY, mode);
}
#ifdef HAVE_CHMOD
int do_chmod(const char *path, mode_t mode)
{
static int switch_step = 0;
int code;
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
switch (switch_step) {
#ifdef HAVE_LCHMOD
case 0:
if ((code = lchmod(path, mode & CHMOD_BITS)) == 0)
break;
if (errno == ENOSYS)
switch_step++;
else if (errno != ENOTSUP)
break;
#endif
/* FALLTHROUGH */
default:
if (S_ISLNK(mode)) {
# if defined HAVE_SETATTRLIST
struct attrlist attrList;
uint32_t m = mode & CHMOD_BITS; /* manpage is wrong: not mode_t! */
memset(&attrList, 0, sizeof attrList);
attrList.bitmapcount = ATTR_BIT_MAP_COUNT;
attrList.commonattr = ATTR_CMN_ACCESSMASK;
if ((code = setattrlist(path, &attrList, &m, sizeof m, FSOPT_NOFOLLOW)) == 0)
break;
if (errno == ENOTSUP)
code = 1;
# else
code = 1;
# endif
} else
code = chmod(path, mode & CHMOD_BITS); /* DISCOURAGED FUNCTION */
break;
}
if (code != 0 && (preserve_perms || preserve_executability))
return code;
return 0;
}
#endif
int do_rename(const char *old_path, const char *new_path)
{
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
return rename(old_path, new_path);
}
#ifdef HAVE_FTRUNCATE
int do_ftruncate(int fd, OFF_T size)
{
int ret;
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
do {
ret = ftruncate(fd, size);
} while (ret < 0 && errno == EINTR);
return ret;
}
#endif
void trim_trailing_slashes(char *name)
{
int l;
/* Some BSD systems cannot make a directory if the name
* contains a trailing slash.
* <http://www.opensource.apple.com/bugs/X/BSD%20Kernel/2734739.html> */
/* Don't change empty string; and also we can't improve on
* "/" */
l = strlen(name);
while (l > 1) {
if (name[--l] != '/')
break;
name[l] = '\0';
}
}
int do_mkdir(char *path, mode_t mode)
{
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
trim_trailing_slashes(path);
return mkdir(path, mode);
}
/* like mkstemp but forces permissions */
int do_mkstemp(char *template, mode_t perms)
{
RETURN_ERROR_IF(dry_run, 0);
RETURN_ERROR_IF(read_only, EROFS);
perms |= S_IWUSR;
#if defined HAVE_SECURE_MKSTEMP && defined HAVE_FCHMOD && (!defined HAVE_OPEN64 || defined HAVE_MKSTEMP64)
{
int fd = mkstemp(template);
if (fd == -1)
return -1;
if (fchmod(fd, perms) != 0 && preserve_perms) {
int errno_save = errno;
close(fd);
unlink(template);
errno = errno_save;
return -1;
}
#if defined HAVE_SETMODE && O_BINARY
setmode(fd, O_BINARY);
#endif
return fd;
}
#else
if (!mktemp(template))
return -1;
return do_open(template, O_RDWR|O_EXCL|O_CREAT, perms);
#endif
}
int do_stat(const char *path, STRUCT_STAT *st)
{
#ifdef USE_STAT64_FUNCS
return stat64(path, st);
#else
return stat(path, st);
#endif
}
int do_lstat(const char *path, STRUCT_STAT *st)
{
#ifdef SUPPORT_LINKS
# ifdef USE_STAT64_FUNCS
return lstat64(path, st);
# else
return lstat(path, st);
# endif
#else
return do_stat(path, st);
#endif
}
int do_fstat(int fd, STRUCT_STAT *st)
{
#ifdef USE_STAT64_FUNCS
return fstat64(fd, st);
#else
return fstat(fd, st);
#endif
}
OFF_T do_lseek(int fd, OFF_T offset, int whence)
{
#ifdef HAVE_LSEEK64
return lseek64(fd, offset, whence);
#else
return lseek(fd, offset, whence);
#endif
}
#ifdef HAVE_SETATTRLIST
int do_setattrlist_times(const char *path, STRUCT_STAT *stp)
{
struct attrlist attrList;
struct timespec ts[2];
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
/* Yes, this is in the opposite order of utime and similar. */
ts[0].tv_sec = stp->st_mtime;
ts[0].tv_nsec = stp->ST_MTIME_NSEC;
ts[1].tv_sec = stp->st_atime;
ts[1].tv_nsec = stp->ST_ATIME_NSEC;
memset(&attrList, 0, sizeof attrList);
attrList.bitmapcount = ATTR_BIT_MAP_COUNT;
attrList.commonattr = ATTR_CMN_MODTIME | ATTR_CMN_ACCTIME;
return setattrlist(path, &attrList, ts, sizeof ts, FSOPT_NOFOLLOW);
}
#ifdef SUPPORT_CRTIMES
int do_setattrlist_crtime(const char *path, time_t crtime)
{
struct attrlist attrList;
struct timespec ts;
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
ts.tv_sec = crtime;
ts.tv_nsec = 0;
memset(&attrList, 0, sizeof attrList);
attrList.bitmapcount = ATTR_BIT_MAP_COUNT;
attrList.commonattr = ATTR_CMN_CRTIME;
return setattrlist(path, &attrList, &ts, sizeof ts, FSOPT_NOFOLLOW);
}
#endif
#endif /* HAVE_SETATTRLIST */
#ifdef SUPPORT_CRTIMES
time_t get_create_time(const char *path, STRUCT_STAT *stp)
{
#ifdef HAVE_GETATTRLIST
static struct create_time attrBuf;
struct attrlist attrList;
(void)stp;
memset(&attrList, 0, sizeof attrList);
attrList.bitmapcount = ATTR_BIT_MAP_COUNT;
attrList.commonattr = ATTR_CMN_CRTIME;
if (getattrlist(path, &attrList, &attrBuf, sizeof attrBuf, FSOPT_NOFOLLOW) < 0)
return 0;
return attrBuf.crtime.tv_sec;
#elif defined __CYGWIN__
(void)path;
return stp->st_birthtime;
#else
#error Unknown crtimes implementation
#endif
}
#if defined __CYGWIN__
int do_SetFileTime(const char *path, time_t crtime)
{
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
int cnt = MultiByteToWideChar(CP_UTF8, 0, path, -1, NULL, 0);
if (cnt == 0)
return -1;
WCHAR *pathw = new_array(WCHAR, cnt);
if (!pathw)
return -1;
MultiByteToWideChar(CP_UTF8, 0, path, -1, pathw, cnt);
HANDLE handle = CreateFileW(pathw, FILE_WRITE_ATTRIBUTES, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
free(pathw);
if (handle == INVALID_HANDLE_VALUE)
return -1;
int64 temp_time = (crtime * 10000000LL) + 116444736000000000LL;
FILETIME birth_time;
birth_time.dwLowDateTime = (DWORD)temp_time;
birth_time.dwHighDateTime = (DWORD)(temp_time >> 32);
int ok = SetFileTime(handle, &birth_time, NULL, NULL);
CloseHandle(handle);
return ok ? 0 : -1;
}
#endif
#endif /* SUPPORT_CRTIMES */
#ifdef HAVE_UTIMENSAT
int do_utimensat(const char *path, STRUCT_STAT *stp)
{
struct timespec t[2];
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
t[0].tv_sec = stp->st_atime;
#ifdef ST_ATIME_NSEC
t[0].tv_nsec = stp->ST_ATIME_NSEC;
#else
t[0].tv_nsec = 0;
#endif
t[1].tv_sec = stp->st_mtime;
#ifdef ST_MTIME_NSEC
t[1].tv_nsec = stp->ST_MTIME_NSEC;
#else
t[1].tv_nsec = 0;
#endif
return utimensat(AT_FDCWD, path, t, AT_SYMLINK_NOFOLLOW);
}
#endif
#ifdef HAVE_LUTIMES
int do_lutimes(const char *path, STRUCT_STAT *stp)
{
struct timeval t[2];
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
t[0].tv_sec = stp->st_atime;
#ifdef ST_ATIME_NSEC
t[0].tv_usec = stp->ST_ATIME_NSEC / 1000;
#else
t[0].tv_usec = 0;
#endif
t[1].tv_sec = stp->st_mtime;
#ifdef ST_MTIME_NSEC
t[1].tv_usec = stp->ST_MTIME_NSEC / 1000;
#else
t[1].tv_usec = 0;
#endif
return lutimes(path, t);
}
#endif
#ifdef HAVE_UTIMES
int do_utimes(const char *path, STRUCT_STAT *stp)
{
struct timeval t[2];
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
t[0].tv_sec = stp->st_atime;
#ifdef ST_ATIME_NSEC
t[0].tv_usec = stp->ST_ATIME_NSEC / 1000;
#else
t[0].tv_usec = 0;
#endif
t[1].tv_sec = stp->st_mtime;
#ifdef ST_MTIME_NSEC
t[1].tv_usec = stp->ST_MTIME_NSEC / 1000;
#else
t[1].tv_usec = 0;
#endif
return utimes(path, t);
}
#elif defined HAVE_UTIME
int do_utime(const char *path, STRUCT_STAT *stp)
{
#ifdef HAVE_STRUCT_UTIMBUF
struct utimbuf tbuf;
#else
time_t t[2];
#endif
if (dry_run) return 0;
RETURN_ERROR_IF_RO_OR_LO;
# ifdef HAVE_STRUCT_UTIMBUF
tbuf.actime = stp->st_atime;
tbuf.modtime = stp->st_mtime;
return utime(path, &tbuf);
# else
t[0] = stp->st_atime;
t[1] = stp->st_mtime;
return utime(path, t);
# endif
}
#else
#error Need utimes or utime function.
#endif
#ifdef SUPPORT_PREALLOCATION
#ifdef FALLOC_FL_KEEP_SIZE
#define DO_FALLOC_OPTIONS FALLOC_FL_KEEP_SIZE
#else
#define DO_FALLOC_OPTIONS 0
#endif
OFF_T do_fallocate(int fd, OFF_T offset, OFF_T length)
{
int opts = inplace || preallocate_files ? DO_FALLOC_OPTIONS : 0;
int ret;
RETURN_ERROR_IF(dry_run, 0);
RETURN_ERROR_IF_RO_OR_LO;
if (length & 1) /* make the length not match the desired length */
length++;
else
length--;
#if defined HAVE_FALLOCATE
ret = fallocate(fd, opts, offset, length);
#elif defined HAVE_SYS_FALLOCATE
ret = syscall(SYS_fallocate, fd, opts, (loff_t)offset, (loff_t)length);
#elif defined HAVE_EFFICIENT_POSIX_FALLOCATE
ret = posix_fallocate(fd, offset, length);
#else
#error Coding error in SUPPORT_PREALLOCATION logic.
#endif
if (ret < 0)
return ret;
if (opts == 0) {
STRUCT_STAT st;
if (do_fstat(fd, &st) < 0)
return length;
return st.st_blocks * S_BLKSIZE;
}
return 0;
}
#endif
/* Punch a hole at pos for len bytes. The current file position must be at pos and will be
* changed to be at pos + len. */
int do_punch_hole(int fd, OFF_T pos, OFF_T len)
{
#ifdef HAVE_FALLOCATE
# ifdef HAVE_FALLOC_FL_PUNCH_HOLE
if (fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, pos, len) == 0) {
if (do_lseek(fd, len, SEEK_CUR) != pos + len)
return -1;
return 0;
}
# endif
# ifdef HAVE_FALLOC_FL_ZERO_RANGE
if (fallocate(fd, FALLOC_FL_ZERO_RANGE, pos, len) == 0) {
if (do_lseek(fd, len, SEEK_CUR) != pos + len)
return -1;
return 0;
}
# endif
#else
(void)pos;
#endif
{
char zeros[4096];
memset(zeros, 0, sizeof zeros);
while (len > 0) {
int chunk = len > (int)sizeof zeros ? (int)sizeof zeros : len;
int wrote = write(fd, zeros, chunk);
if (wrote <= 0) {
if (wrote < 0 && errno == EINTR)
continue;
return -1;
}
len -= wrote;
}
}
return 0;
}
int do_open_nofollow(const char *pathname, int flags)
{
#ifndef O_NOFOLLOW
STRUCT_STAT f_st, l_st;
#endif
int fd;
if (flags != O_RDONLY) {
RETURN_ERROR_IF(dry_run, 0);
RETURN_ERROR_IF_RO_OR_LO;
#ifndef O_NOFOLLOW
/* This function doesn't support write attempts w/o O_NOFOLLOW. */
errno = EINVAL;
return -1;
#endif
}
#ifdef O_NOATIME
if (open_noatime)
flags |= O_NOATIME;
#endif
#ifdef O_NOFOLLOW
fd = open(pathname, flags|O_NOFOLLOW);
#else
if (do_lstat(pathname, &l_st) < 0)
return -1;
if (S_ISLNK(l_st.st_mode)) {
errno = ELOOP;
return -1;
}
if ((fd = open(pathname, flags)) < 0)
return fd;
if (do_fstat(fd, &f_st) < 0) {
close_and_return_error:
{
int save_errno = errno;
close(fd);
errno = save_errno;
}
return -1;
}
if (l_st.st_dev != f_st.st_dev || l_st.st_ino != f_st.st_ino) {
errno = EINVAL;
goto close_and_return_error;
}
#endif
return fd;
}
/*
open a file relative to a base directory. The basedir can be NULL,
in which case the current working directory is used. The relpath
must be a relative path, and the relpath must not contain any
elements in the path which follow symlinks (ie. like O_NOFOLLOW, but
applies to all path components, not just the last component)
The relpath must also not contain any ../ elements in the path
*/
int secure_relative_open(const char *basedir, const char *relpath, int flags, mode_t mode)
{
if (!relpath || relpath[0] == '/') {
// must be a relative path
errno = EINVAL;
return -1;
}
if (strncmp(relpath, "../", 3) == 0 || strstr(relpath, "/../")) {
// no ../ elements allowed in the relpath
errno = EINVAL;
return -1;
}
#if !defined(O_NOFOLLOW) || !defined(O_DIRECTORY) || !defined(AT_FDCWD)
// really old system, all we can do is live with the risks
if (!basedir) {
return open(relpath, flags, mode);
}
char fullpath[MAXPATHLEN];
pathjoin(fullpath, sizeof fullpath, basedir, relpath);
return open(fullpath, flags, mode);
#else
int dirfd = AT_FDCWD;
if (basedir != NULL) {
dirfd = openat(AT_FDCWD, basedir, O_RDONLY | O_DIRECTORY);
if (dirfd == -1) {
return -1;
}
}
int retfd = -1;
char *path_copy = my_strdup(relpath, __FILE__, __LINE__);
if (!path_copy) {
return -1;
}
for (const char *part = strtok(path_copy, "/");
part != NULL;
part = strtok(NULL, "/"))
{
int next_fd = openat(dirfd, part, O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
if (next_fd == -1 && errno == ENOTDIR) {
if (strtok(NULL, "/") != NULL) {
// this is not the last component of the path
errno = ELOOP;
goto cleanup;
}
// this could be the last component of the path, try as a file
retfd = openat(dirfd, part, flags | O_NOFOLLOW, mode);
goto cleanup;
}
if (next_fd == -1) {
goto cleanup;
}
if (dirfd != AT_FDCWD) close(dirfd);
dirfd = next_fd;
}
// the path must be a directory
errno = EINVAL;
cleanup:
free(path_copy);
if (dirfd != AT_FDCWD) {
close(dirfd);
}
return retfd;
#endif // O_NOFOLLOW, O_DIRECTORY
}
/*
varient of do_open/do_open_nofollow which does do_open() if the
copy_links or copy_unsafe_links options are set and does
do_open_nofollow() otherwise
This is used to prevent a race condition where an attacker could be
switching a file between being a symlink and being a normal file
The open is always done with O_RDONLY flags
*/
int do_open_checklinks(const char *pathname)
{
if (copy_links || copy_unsafe_links) {
return do_open(pathname, O_RDONLY, 0);
}
return do_open_nofollow(pathname, O_RDONLY);
}