1 This patch adds a new option: --fake-super, which tells rsync to copy in a
2 fake super-user mode that stores various file attributes in an extended-
3 attribute value instead of as real file-system attributes. See the changes
4 to the manpages for details.
6 To use this patch, run these commands for a successful build:
8 patch -p1 <patches/acls.diff
9 patch -p1 <patches/xattrs.diff
10 patch -p1 <patches/fake-super.diff
12 ./configure --enable-xattr-support
15 If you want ACL support too, use this configure command instead of the one
18 ./configure --enable-acl-support --enable-xattr-support
22 @@ -129,7 +129,7 @@ static int make_bak_dir(char *fullpath)
24 /* Try to transfer the directory settings of the
25 * actual dir that the files are coming from. */
26 - if (do_stat(rel, &sx.st) < 0) {
27 + if (x_stat(rel, &sx.st, NULL) < 0) {
28 rsyserr(FERROR, errno,
29 "make_bak_dir stat %s failed",
31 @@ -200,7 +200,7 @@ static int keep_backup(char *fname)
34 /* return if no file to keep */
35 - if (do_lstat(fname, &sx.st) < 0)
36 + if (x_lstat(fname, &sx.st, NULL) < 0)
39 sx.acc_acl = sx.def_acl = NULL;
40 --- old/clientserver.c
41 +++ new/clientserver.c
42 @@ -625,6 +625,11 @@ static int rsync_module(int f_in, int f_
43 ret = parse_arguments(&argc, (const char ***) &argv, 0);
44 quiet = 0; /* Don't let someone try to be tricky. */
46 + if (lp_fake_super(i))
48 + else if (am_root < 0) /* Treat --fake-super from client as --super. */
51 if (filesfrom_fd == 0)
56 @@ -181,7 +181,7 @@ static int readlink_stat(const char *pat
60 - return do_stat(path, stp);
61 + return x_stat(path, stp, NULL);
65 @@ -189,17 +189,17 @@ int link_stat(const char *path, STRUCT_S
69 - return do_stat(path, stp);
70 - if (do_lstat(path, stp) < 0)
71 + return x_stat(path, stp, NULL);
72 + if (x_lstat(path, stp, NULL) < 0)
74 if (follow_dirlinks && S_ISLNK(stp->st_mode)) {
76 - if (do_stat(path, &st) == 0 && S_ISDIR(st.st_mode))
77 + if (x_stat(path, &st, NULL) == 0 && S_ISDIR(st.st_mode))
82 - return do_stat(path, stp);
83 + return x_stat(path, stp, NULL);
87 @@ -234,26 +234,6 @@ static int is_excluded(char *fname, int
91 -static int to_wire_mode(mode_t mode)
94 -#if _S_IFLNK != 0120000
96 - return (mode & ~(_S_IFMT)) | 0120000;
102 -static mode_t from_wire_mode(int mode)
104 -#if _S_IFLNK != 0120000
105 - if ((mode & (_S_IFMT)) == 0120000)
106 - return (mode & ~(_S_IFMT)) | _S_IFLNK;
111 static void send_directory(int f, struct file_list *flist,
112 char *fbuf, int len);
114 @@ -793,7 +773,7 @@ struct file_struct *make_file(char *fnam
115 if (save_errno == ENOENT) {
117 /* Avoid "vanished" error if symlink points nowhere. */
118 - if (copy_links && do_lstat(thisname, &st) == 0
119 + if (copy_links && x_lstat(thisname, &st, NULL) == 0
120 && S_ISLNK(st.st_mode)) {
121 io_error |= IOERR_GENERAL;
122 rprintf(FERROR, "symlink has no referent: %s\n",
123 @@ -963,7 +943,7 @@ struct file_struct *make_file(char *fnam
124 int save_mode = file->mode;
125 file->mode = S_IFDIR; /* Find a directory with our name. */
126 if (flist_find(the_file_list, file) >= 0
127 - && do_stat(thisname, &st2) == 0 && S_ISDIR(st2.st_mode)) {
128 + && x_stat(thisname, &st2, NULL) == 0 && S_ISDIR(st2.st_mode)) {
129 file->modtime = st2.st_mtime;
130 file->length = st2.st_size;
131 file->mode = st2.st_mode;
134 @@ -150,6 +150,7 @@ typedef struct
140 BOOL ignore_nonreadable;
142 @@ -197,6 +198,7 @@ static service sDefault =
143 /* syslog_facility; */ LOG_DAEMON,
146 + /* fake_super; */ False,
147 /* ignore_errors; */ False,
148 /* ignore_nonreadable; */ False,
150 @@ -298,6 +300,7 @@ static struct parm_struct parm_table[] =
151 {"dont compress", P_STRING, P_LOCAL, &sDefault.dont_compress, NULL,0},
152 {"exclude from", P_STRING, P_LOCAL, &sDefault.exclude_from, NULL,0},
153 {"exclude", P_STRING, P_LOCAL, &sDefault.exclude, NULL,0},
154 + {"fake super", P_BOOL, P_LOCAL, &sDefault.fake_super, NULL,0},
155 {"filter", P_STRING, P_LOCAL, &sDefault.filter, NULL,0},
156 {"gid", P_STRING, P_LOCAL, &sDefault.gid, NULL,0},
157 {"hosts allow", P_STRING, P_LOCAL, &sDefault.hosts_allow, NULL,0},
158 @@ -412,6 +415,7 @@ FN_LOCAL_INTEGER(lp_max_connections, max
159 FN_LOCAL_INTEGER(lp_max_verbosity, max_verbosity)
160 FN_LOCAL_INTEGER(lp_timeout, timeout)
162 +FN_LOCAL_BOOL(lp_fake_super, fake_super)
163 FN_LOCAL_BOOL(lp_ignore_errors, ignore_errors)
164 FN_LOCAL_BOOL(lp_ignore_nonreadable, ignore_nonreadable)
165 FN_LOCAL_BOOL(lp_list, list)
166 @@ -816,7 +820,7 @@ BOOL lp_load(char *pszFname, int globals
169 pstrcpy(n2,pszFname);
170 - else if (am_server && !am_root)
171 + else if (am_server && am_root <= 0)
172 pstrcpy(n2,RSYNCD_USERCONF);
174 pstrcpy(n2,RSYNCD_SYSCONF);
177 @@ -73,7 +73,7 @@ int protocol_version = PROTOCOL_VERSION;
178 int sparse_files = 0;
179 int do_compression = 0;
180 int def_compress_level = Z_DEFAULT_COMPRESSION;
182 +int am_root = 0; /* 0 = normal, 1 = root, 2 = --super, -1 = --fake-super */
185 int am_generator = 0;
186 @@ -329,6 +329,9 @@ void usage(enum logcode F)
187 rprintf(F," -t, --times preserve times\n");
188 rprintf(F," -O, --omit-dir-times omit directories when preserving times\n");
189 rprintf(F," --super receiver attempts super-user activities\n");
190 +#ifdef SUPPORT_XATTRS
191 + rprintf(F," --fake-super store/recover privileged attrs using xattrs\n");
193 rprintf(F," -S, --sparse handle sparse files efficiently\n");
194 rprintf(F," -n, --dry-run show what would have been transferred\n");
195 rprintf(F," -W, --whole-file copy files whole (without rsync algorithm)\n");
196 @@ -453,6 +456,7 @@ static struct poptOption long_options[]
197 {"modify-window", 0, POPT_ARG_INT, &modify_window, OPT_MODIFY_WINDOW, 0, 0 },
198 {"super", 0, POPT_ARG_VAL, &am_root, 2, 0, 0 },
199 {"no-super", 0, POPT_ARG_VAL, &am_root, 0, 0, 0 },
200 + {"fake-super", 0, POPT_ARG_VAL, &am_root, -1, 0, 0 },
201 {"owner", 'o', POPT_ARG_VAL, &preserve_uid, 1, 0, 0 },
202 {"no-owner", 0, POPT_ARG_VAL, &preserve_uid, 0, 0, 0 },
203 {"no-o", 0, POPT_ARG_VAL, &preserve_uid, 0, 0, 0 },
204 @@ -1178,6 +1182,14 @@ int parse_arguments(int *argc, const cha
208 +#ifndef SUPPORT_XATTRS
210 + snprintf(err_buf, sizeof err_buf,
211 + "--fake-super requires an rsync with extended attributes enabled\n");
216 if (write_batch && read_batch) {
217 snprintf(err_buf, sizeof err_buf,
218 "--write-batch and --read-batch can not be used together\n");
221 @@ -196,7 +196,9 @@ int set_file_attrs(char *fname, struct f
222 (long)sxp->st.st_gid, (long)file->gid);
225 - if (do_lchown(fname,
228 + } else if (do_lchown(fname,
229 change_uid ? file->uid : sxp->st.st_uid,
230 change_gid ? file->gid : sxp->st.st_gid) != 0) {
231 /* shouldn't have attempted to change uid or gid
232 @@ -205,7 +207,7 @@ int set_file_attrs(char *fname, struct f
233 change_uid ? "chown" : "chgrp",
238 /* a lchown had been done - we have to re-stat if the
239 * destination had the setuid or setgid bits set due
240 * to the side effect of the chown call */
241 @@ -222,6 +224,8 @@ int set_file_attrs(char *fname, struct f
242 #ifdef SUPPORT_XATTRS
243 if (preserve_xattrs && set_xattr(fname, file, sxp) == 0)
246 + set_stat_xattr(fname, file);
249 /* It's OK to call set_acl() now, even for a dir, as the generator
250 @@ -236,7 +240,7 @@ int set_file_attrs(char *fname, struct f
253 if ((sxp->st.st_mode & CHMOD_BITS) != (new_mode & CHMOD_BITS)) {
254 - int ret = do_chmod(fname, new_mode);
255 + int ret = am_root < 0 ? 0 : do_chmod(fname, new_mode);
257 rsyserr(FERROR, errno,
258 "failed to set permissions on %s",
261 @@ -707,6 +707,12 @@ typedef struct {
265 +#ifndef SUPPORT_XATTRS
266 +#define x_stat(fn,fst,xst) do_stat(fn,fst)
267 +#define x_lstat(fn,fst,xst) do_lstat(fn,fst)
268 +#define x_fstat(fd,fst,xst) do_fstat(fd,fst)
271 /* We have replacement versions of these if they're missing. */
272 #ifndef HAVE_ASPRINTF
273 int asprintf(char **ptr, const char *format, ...);
274 @@ -924,3 +930,23 @@ int inet_pton(int af, const char *src, v
275 #ifdef MAINTAINER_MODE
276 const char *get_panic_action(void);
279 +static inline int to_wire_mode(mode_t mode)
281 +#ifdef SUPPORT_LINKS
282 +#if _S_IFLNK != 0120000
284 + return (mode & ~(_S_IFMT)) | 0120000;
290 +static inline mode_t from_wire_mode(int mode)
292 +#if _S_IFLNK != 0120000
293 + if ((mode & (_S_IFMT)) == 0120000)
294 + return (mode & ~(_S_IFMT)) | _S_IFLNK;
300 @@ -333,6 +333,7 @@ to the detailed description below for a
301 -t, --times preserve times
302 -O, --omit-dir-times omit directories when preserving times
303 --super receiver attempts super-user activities
304 + --fake-super store/recover privileged attrs using xattrs
305 -S, --sparse handle sparse files efficiently
306 -n, --dry-run show what would have been transferred
307 -W, --whole-file copy files whole (without rsync algorithm)
308 @@ -846,7 +847,7 @@ permission value can be applied to the f
309 dit(bf(-o, --owner)) This option causes rsync to set the owner of the
310 destination file to be the same as the source file, but only if the
311 receiving rsync is being run as the super-user (see also the bf(--super)
312 -option to force rsync to attempt super-user activities).
313 +and bf(--fake-super) options).
314 Without this option, the owner is set to the invoking user on the
317 @@ -869,7 +870,7 @@ default, but may fall back to using the
318 dit(bf(--devices)) This option causes rsync to transfer character and
319 block device files to the remote system to recreate these devices.
320 This option has no effect if the receiving rsync is not run as the
321 -super-user and bf(--super) is not specified.
322 +super-user (see also the bf(--super) and bf(--fake-super) options).
324 dit(bf(--specials)) This option causes rsync to transfer special files
325 such as named sockets and fifos.
326 @@ -899,6 +900,33 @@ also for ensuring that you will get erro
327 being running as the super-user. To turn off super-user activities, the
328 super-user can use bf(--no-super).
330 +dit(bf(--fake-super)) When this option is enabled, rsync simulates
331 +super-user activities by saving/restoring the privileged attributes via a
332 +special extended attribute that is attached to each file (as needed). This
333 +includes the file's owner and group (if it is not the default), the file's
334 +device info (device & special files are created as empty text files), and
335 +any permission bits that we won't allow to be set on the real file (e.g.
336 +the real file gets u-s,g-s,o-t for safety) or that would limit the owner's
337 +access (since the real super-user can always access/change a file or
338 +directory, the files we create can always be accessed/changed by the
341 +The bf(--fake-super) option only affects the side where the option is used.
342 +To affect the remote side of a remote-shell connection, specify an rsync
345 +quote(tt( rsync -av --rsync-path="rsync --fake-super" /src/ host:/dest/))
347 +Since there is only one "side" in a local copy, this option affects both
348 +the sending and recieving of files. You'll need to specify a copy using
349 +"localhost" if you need to avoid this. Note, however, that it is always
350 +safe to copy from some non-fake-super files into some fake-super files
351 +using a local bf(--fake-super) command because the non-fake source files
352 +will just have their normal attributes.
354 +See also the "fake super" setting in the daemon's rsyncd.conf file.
355 +This option is overridden by both bf(--super) and bf(--no-super).
357 dit(bf(-S, --sparse)) Try to handle sparse files efficiently so they take
358 up less space on the destination. Conflicts with bf(--inplace) because it's
359 not possible to overwrite data in a sparse fashion.
360 --- old/rsyncd.conf.yo
361 +++ new/rsyncd.conf.yo
362 @@ -226,6 +226,11 @@ file transfers to and from that module s
363 was run as root. This complements the "uid" option. The default is gid -2,
364 which is normally the group "nobody".
366 +dit(bf(fake super)) Setting "fake super = yes" for a module causes the
367 +daemon side to behave as if the bf(--fake-user) command-line option had
368 +been specified. This allows the full attributes of a file to be stored
369 +without having to have the daemon actually running as root.
371 dit(bf(filter)) The "filter" option allows you to specify a space-separated
372 list of filter rules that the daemon will not allow to be read or written.
373 This is only superficially equivalent to the client specifying these
381 extern int read_only;
382 extern int list_only;
383 extern int preserve_perms;
384 @@ -79,6 +80,15 @@ int do_mknod(char *pathname, mode_t mode
386 if (dry_run) return 0;
387 RETURN_ERROR_IF_RO_OR_LO;
389 + /* For --fake-super, we create a normal file with mode 0600. */
391 + int fd = open(pathname, O_WRONLY|O_CREAT|O_TRUNC, S_IWUSR|S_IRUSR);
392 + if (fd < 0 || close(fd) < 0)
397 #if !defined MKNOD_CREATES_FIFOS && defined HAVE_MKFIFO
399 return mkfifo(pathname, mode);
406 -int dry_run, read_only, list_only, verbose;
412 int preserve_perms = 0;
419 /* These are to make syscall.o shut up. */
424 int preserve_perms = 0;
429 /* These are to make syscall.o shut up. */
434 int preserve_perms = 0;
437 @@ -39,6 +39,12 @@ extern unsigned int file_struct_len;
438 #define ROOT_PREFIX "root."
439 #define RPRE_LEN (sizeof ROOT_PREFIX - 1)
441 +#ifdef HAVE_LINUX_XATTRS
442 +#define FAKE_XATTR USER_PREFIX "rsync.%stat"
444 +#define FAKE_XATTR "rsync.%stat"
450 @@ -144,6 +150,10 @@ static int rsync_xal_get(const char *fna
454 + if (am_root < 0 && len == sizeof FAKE_XATTR
455 + && name[11] == '%' && strcmp(name, FAKE_XATTR) == 0)
458 rxas = EXPAND_ITEM_LIST(xalp, rsync_xa, RSYNC_XAL_INITIAL);
460 datum_size = sys_lgetxattr(fname, name, NULL, 0);
461 @@ -315,6 +325,12 @@ void receive_xattr(struct file_struct *f
462 memmove(ptr, ptr + UPRE_LEN, rxa->name_len);
465 + if (am_root < 0 && name_len == sizeof FAKE_XATTR
466 + && ptr[11] == '%' && strcmp(ptr, FAKE_XATTR) == 0) {
468 + temp_xattr.count--;
472 ndx = rsync_xal_l.count; /* pre-incremented count */
473 rsync_xal_store(&temp_xattr); /* adds item to rsync_xal_l */
474 @@ -390,4 +406,146 @@ int set_xattr(const char *fname, const s
475 return rsync_xal_set(fname, lst + ndx); /* TODO: This needs to return 1 if no xattrs changed! */
478 +int get_stat_xattr(const char *fname, int fd, STRUCT_STAT *fst, STRUCT_STAT *xst)
480 + int mode, rdev_major, rdev_minor, uid, gid, len;
483 + if (am_root >= 0 || IS_DEVICE(fst->st_mode) || IS_SPECIAL(fst->st_mode))
492 + len = sys_lgetxattr(fname, FAKE_XATTR, buf, sizeof buf - 1);
495 + len = sys_fgetxattr(fd, FAKE_XATTR, buf, sizeof buf - 1);
497 + if (len >= (int)sizeof buf) {
502 + if (errno == ENOTSUP || errno == ENOATTR)
504 + if (errno == EPERM && S_ISLNK(fst->st_mode)) {
509 + rsyserr(FERROR, errno, "failed to read xattr %s for %s",
510 + FAKE_XATTR, full_fname(fname));
515 + if (sscanf(buf, "%o %d,%d %d:%d",
516 + &mode, &rdev_major, &rdev_minor, &uid, &gid) != 5) {
517 + rprintf(FERROR, "Corrupt %s xattr attached to %s: \"%s\"\n",
518 + FAKE_XATTR, full_fname(fname), buf);
519 + exit_cleanup(RERR_FILEIO);
522 + xst->st_mode = from_wire_mode(mode);
523 + xst->st_rdev = MAKEDEV(rdev_major, rdev_minor);
530 +int set_stat_xattr(const char *fname, struct file_struct *file)
532 + STRUCT_STAT fst, xst;
539 + if (read_only || list_only) {
540 + rsyserr(FERROR, EROFS, "failed to write xattr %s for %s",
541 + FAKE_XATTR, full_fname(fname));
545 + if (x_lstat(fname, &fst, &xst) < 0) {
546 + rsyserr(FERROR, errno, "failed to re-stat %s",
547 + full_fname(fname));
551 + if (IS_DEVICE(file->mode) || IS_SPECIAL(file->mode))
552 + rdev = file->u.rdev;
556 + /* Dump the special permissions and enable full owner access. */
557 + mode = (fst.st_mode & ~CHMOD_BITS) | (file->mode & ACCESSPERMS)
558 + | (S_ISDIR(fst.st_mode) ? 0700 : 0600);
559 + if (fst.st_mode != mode)
560 + do_chmod(fname, mode);
561 + if (!IS_DEVICE(fst.st_mode) && !IS_SPECIAL(fst.st_mode))
562 + fst.st_rdev = 0; /* just in case */
564 + if (mode == file->mode && fst.st_rdev == rdev
565 + && fst.st_uid == file->uid && fst.st_gid == file->gid) {
566 + /* xst.st_mode will be 0 if there's no current stat xattr */
567 + if (xst.st_mode && sys_lremovexattr(fname, FAKE_XATTR) < 0) {
568 + rsyserr(FERROR, errno,
569 + "delete of stat xattr failed for %s",
570 + full_fname(fname));
576 + if (xst.st_mode != file->mode || xst.st_rdev != rdev
577 + || xst.st_uid != file->uid || xst.st_gid != file->gid) {
579 + int len = snprintf(buf, sizeof buf, "%o %u,%u %u:%u",
580 + to_wire_mode(file->mode) & (_S_IFMT|CHMOD_BITS),
581 + (int)major(rdev), (int)minor(rdev),
582 + (int)file->uid, (int)file->gid);
583 + if (sys_lsetxattr(fname, FAKE_XATTR, buf, len) < 0) {
584 + if (errno == EPERM && S_ISLNK(fst.st_mode))
586 + rsyserr(FERROR, errno,
587 + "failed to write xattr %s for %s",
588 + FAKE_XATTR, full_fname(fname));
596 +int x_stat(const char *fname, STRUCT_STAT *fst, STRUCT_STAT *xst)
598 + int ret = do_stat(fname, fst);
599 + if ((ret < 0 || get_stat_xattr(fname, -1, fst, xst) < 0) && xst)
604 +int x_lstat(const char *fname, STRUCT_STAT *fst, STRUCT_STAT *xst)
606 + int ret = do_lstat(fname, fst);
607 + if ((ret < 0 || get_stat_xattr(fname, -1, fst, xst) < 0) && xst)
612 +int x_fstat(int fd, STRUCT_STAT *fst, STRUCT_STAT *xst)
614 + int ret = do_fstat(fd, fst);
615 + if ((ret < 0 || get_stat_xattr(NULL, fd, fst, xst) < 0) && xst)
620 #endif /* SUPPORT_XATTRS */