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 @@ -128,7 +128,7 @@ 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 @@ -199,7 +199,7 @@ static int keep_backup(const 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 @@ -627,6 +627,11 @@ 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 @@ -193,7 +193,7 @@ static int readlink_stat(const char *pat
60 - return do_stat(path, stp);
61 + return x_stat(path, stp, NULL);
65 @@ -201,17 +201,17 @@ 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 @@ -246,26 +246,6 @@ 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 @@ -877,7 +857,7 @@ struct file_struct *make_file(const char
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 @@ -1050,7 +1030,7 @@ struct file_struct *make_file(const char
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;
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 @@ -815,7 +819,7 @@ 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 @@ -325,6 +325,9 @@ 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 @@ -450,6 +453,7 @@ 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 @@ -1176,6 +1180,14 @@ 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 @@ -249,7 +249,9 @@ int set_file_attrs(char *fname, struct f
222 (long)sxp->st.st_gid, (long)F_GID(file));
225 - if (do_lchown(fname,
228 + } else if (do_lchown(fname,
229 change_uid ? F_UID(file) : sxp->st.st_uid,
230 change_gid ? F_GID(file) : sxp->st.st_gid) != 0) {
231 /* shouldn't have attempted to change uid or gid
232 @@ -258,7 +260,7 @@ 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 @@ -275,6 +277,8 @@ 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 @@ -289,7 +293,7 @@ int set_file_attrs(char *fname, struct f
253 if (!BITS_EQUAL(sxp->st.st_mode, 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 @@ -783,6 +783,12 @@ 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 @@ -1001,6 +1007,26 @@ int inet_pton(int af, const char *src, v
275 const char *get_panic_action(void);
278 +static inline int to_wire_mode(mode_t mode)
280 +#ifdef SUPPORT_LINKS
281 +#if _S_IFLNK != 0120000
283 + return (mode & ~(_S_IFMT)) | 0120000;
289 +static inline mode_t from_wire_mode(int mode)
291 +#if _S_IFLNK != 0120000
292 + if ((mode & (_S_IFMT)) == 0120000)
293 + return (mode & ~(_S_IFMT)) | _S_IFLNK;
299 isDigit(const char *ptr)
303 @@ -333,6 +333,7 @@ to the detailed description below for a
304 -t, --times preserve times
305 -O, --omit-dir-times omit directories when preserving times
306 --super receiver attempts super-user activities
307 + --fake-super store/recover privileged attrs using xattrs
308 -S, --sparse handle sparse files efficiently
309 -n, --dry-run show what would have been transferred
310 -W, --whole-file copy files whole (without rsync algorithm)
311 @@ -846,7 +847,7 @@ permission value can be applied to the f
312 dit(bf(-o, --owner)) This option causes rsync to set the owner of the
313 destination file to be the same as the source file, but only if the
314 receiving rsync is being run as the super-user (see also the bf(--super)
315 -option to force rsync to attempt super-user activities).
316 +and bf(--fake-super) options).
317 Without this option, the owner is set to the invoking user on the
320 @@ -869,7 +870,7 @@ default, but may fall back to using the
321 dit(bf(--devices)) This option causes rsync to transfer character and
322 block device files to the remote system to recreate these devices.
323 This option has no effect if the receiving rsync is not run as the
324 -super-user and bf(--super) is not specified.
325 +super-user (see also the bf(--super) and bf(--fake-super) options).
327 dit(bf(--specials)) This option causes rsync to transfer special files
328 such as named sockets and fifos.
329 @@ -899,6 +900,33 @@ also for ensuring that you will get erro
330 being running as the super-user. To turn off super-user activities, the
331 super-user can use bf(--no-super).
333 +dit(bf(--fake-super)) When this option is enabled, rsync simulates
334 +super-user activities by saving/restoring the privileged attributes via a
335 +special extended attribute that is attached to each file (as needed). This
336 +includes the file's owner and group (if it is not the default), the file's
337 +device info (device & special files are created as empty text files), and
338 +any permission bits that we won't allow to be set on the real file (e.g.
339 +the real file gets u-s,g-s,o-t for safety) or that would limit the owner's
340 +access (since the real super-user can always access/change a file or
341 +directory, the files we create can always be accessed/changed by the
344 +The bf(--fake-super) option only affects the side where the option is used.
345 +To affect the remote side of a remote-shell connection, specify an rsync
348 +quote(tt( rsync -av --rsync-path="rsync --fake-super" /src/ host:/dest/))
350 +Since there is only one "side" in a local copy, this option affects both
351 +the sending and recieving of files. You'll need to specify a copy using
352 +"localhost" if you need to avoid this. Note, however, that it is always
353 +safe to copy from some non-fake-super files into some fake-super files
354 +using a local bf(--fake-super) command because the non-fake source files
355 +will just have their normal attributes.
357 +See also the "fake super" setting in the daemon's rsyncd.conf file.
358 +This option is overridden by both bf(--super) and bf(--no-super).
360 dit(bf(-S, --sparse)) Try to handle sparse files efficiently so they take
361 up less space on the destination. Conflicts with bf(--inplace) because it's
362 not possible to overwrite data in a sparse fashion.
363 --- old/rsyncd.conf.yo
364 +++ new/rsyncd.conf.yo
365 @@ -226,6 +226,11 @@ file transfers to and from that module s
366 was run as root. This complements the "uid" option. The default is gid -2,
367 which is normally the group "nobody".
369 +dit(bf(fake super)) Setting "fake super = yes" for a module causes the
370 +daemon side to behave as if the bf(--fake-user) command-line option had
371 +been specified. This allows the full attributes of a file to be stored
372 +without having to have the daemon actually running as root.
374 dit(bf(filter)) The "filter" option allows you to specify a space-separated
375 list of filter rules that the daemon will not allow to be read or written.
376 This is only superficially equivalent to the client specifying these
384 extern int read_only;
385 extern int list_only;
386 extern int preserve_perms;
387 @@ -79,6 +80,15 @@ int do_mknod(const char *pathname, mode_
389 if (dry_run) return 0;
390 RETURN_ERROR_IF_RO_OR_LO;
392 + /* For --fake-super, we create a normal file with mode 0600. */
394 + int fd = open(pathname, O_WRONLY|O_CREAT|O_TRUNC, S_IWUSR|S_IRUSR);
395 + if (fd < 0 || close(fd) < 0)
400 #if !defined MKNOD_CREATES_FIFOS && defined HAVE_MKFIFO
402 return mkfifo(pathname, mode);
409 -int dry_run, read_only, list_only, verbose;
415 int preserve_perms = 0;
422 /* These are to make syscall.o shut up. */
427 int preserve_perms = 0;
432 /* These are to make syscall.o shut up. */
437 int preserve_perms = 0;
440 @@ -42,11 +42,16 @@ extern int list_only;
441 #define SPRE_LEN ((int)sizeof SYSTEM_PREFIX - 1)
443 #ifdef HAVE_LINUX_XATTRS
445 +#define MIGHT_NEED_RPRE (am_root < 0)
446 +#define RSYNC_PREFIX USER_PREFIX "rsync."
448 +#define MIGHT_NEED_RPRE am_root
449 #define RSYNC_PREFIX "rsync."
450 -#define RPRE_LEN ((int)sizeof RSYNC_PREFIX - 1)
452 +#define RPRE_LEN ((int)sizeof RSYNC_PREFIX - 1)
454 +#define XSTAT_ATTR RSYNC_PREFIX "%stat"
455 +#define XSTAT_LEN ((int)sizeof XSTAT_ATTR - 1)
459 @@ -147,6 +152,10 @@ static int rsync_xal_get(const char *fna
463 + if (am_root < 0 && name_len == XSTAT_LEN + 1
464 + && name[RPRE_LEN] == '%' && strcmp(name, XSTAT_ATTR) == 0)
467 datum_len = sys_lgetxattr(fname, name, NULL, 0);
469 if (errno == ENOTSUP)
470 @@ -176,6 +185,13 @@ static int rsync_xal_get(const char *fna
474 +#ifdef HAVE_LINUX_XATTRS
475 + if (am_root < 0 && name_len > RPRE_LEN
476 + && HAS_PREFIX(name, RSYNC_PREFIX)) {
478 + name_len -= RPRE_LEN;
481 rxas = EXPAND_ITEM_LIST(xalp, rsync_xa, RSYNC_XAL_INITIAL);
482 rxas->name = ptr + datum_len;
484 @@ -296,13 +312,9 @@ void receive_xattr(struct file_struct *f
486 size_t name_len = read_int(f);
487 size_t datum_len = read_int(f);
488 -#ifdef HAVE_LINUX_XATTRS
489 - size_t extra_len = 0;
491 - size_t extra_len = am_root ? RPRE_LEN : 0;
492 + size_t extra_len = MIGHT_NEED_RPRE ? RPRE_LEN : 0;
493 if (datum_len + extra_len < datum_len)
494 out_of_memory("receive_xattr"); /* overflow */
496 if (name_len + datum_len + extra_len < name_len)
497 out_of_memory("receive_xattr"); /* overflow */
498 ptr = new_array(char, name_len + datum_len + extra_len);
499 @@ -313,9 +325,14 @@ void receive_xattr(struct file_struct *f
500 read_buf(f, ptr, datum_len);
501 #ifdef HAVE_LINUX_XATTRS
502 /* Non-root can only save the user namespace. */
503 - if (!am_root && !HAS_PREFIX(name, USER_PREFIX)) {
506 + if (am_root <= 0 && !HAS_PREFIX(name, USER_PREFIX)) {
512 + name_len += RPRE_LEN;
513 + memcpy(name, RSYNC_PREFIX, RPRE_LEN);
516 /* This OS only has a user namespace, so we either
517 @@ -333,6 +350,12 @@ void receive_xattr(struct file_struct *f
521 + if (am_root < 0 && name_len == XSTAT_LEN + 1
522 + && name[RPRE_LEN] == '%'
523 + && strcmp(name, XSTAT_ATTR) == 0) {
527 rxa = EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, count);
530 @@ -410,4 +433,150 @@ int set_xattr(const char *fname, const s
531 return rsync_xal_set(fname, lst + ndx); /* TODO: This needs to return 1 if no xattrs changed! */
534 +int get_stat_xattr(const char *fname, int fd, STRUCT_STAT *fst, STRUCT_STAT *xst)
536 + int mode, rdev_major, rdev_minor, uid, gid, len;
539 + if (am_root >= 0 || IS_DEVICE(fst->st_mode) || IS_SPECIAL(fst->st_mode))
548 + len = sys_lgetxattr(fname, XSTAT_ATTR, buf, sizeof buf - 1);
551 + len = sys_fgetxattr(fd, XSTAT_ATTR, buf, sizeof buf - 1);
553 + if (len >= (int)sizeof buf) {
558 + if (errno == ENOTSUP || errno == ENOATTR)
560 + if (errno == EPERM && S_ISLNK(fst->st_mode)) {
565 + rsyserr(FERROR, errno, "failed to read xattr %s for %s",
566 + XSTAT_ATTR, full_fname(fname));
571 + if (sscanf(buf, "%o %d,%d %d:%d",
572 + &mode, &rdev_major, &rdev_minor, &uid, &gid) != 5) {
573 + rprintf(FERROR, "Corrupt %s xattr attached to %s: \"%s\"\n",
574 + XSTAT_ATTR, full_fname(fname), buf);
575 + exit_cleanup(RERR_FILEIO);
578 + xst->st_mode = from_wire_mode(mode);
579 + xst->st_rdev = MAKEDEV(rdev_major, rdev_minor);
586 +int set_stat_xattr(const char *fname, struct file_struct *file)
588 + STRUCT_STAT fst, xst;
590 + mode_t mode, fmode;
595 + if (read_only || list_only) {
596 + rsyserr(FERROR, EROFS, "failed to write xattr %s for %s",
597 + XSTAT_ATTR, full_fname(fname));
601 + if (x_lstat(fname, &fst, &xst) < 0) {
602 + rsyserr(FERROR, errno, "failed to re-stat %s",
603 + full_fname(fname));
607 + fst.st_mode &= (_S_IFMT | CHMOD_BITS);
608 + fmode = file->mode & (_S_IFMT | CHMOD_BITS);
610 + if (IS_DEVICE(fmode) || IS_SPECIAL(fmode)) {
611 + uint32 *devp = F_RDEV_P(file);
612 + rdev = MAKEDEV(DEV_MAJOR(devp), DEV_MINOR(devp));
616 + /* Dump the special permissions and enable full owner access. */
617 + mode = (fst.st_mode & _S_IFMT) | (fmode & ACCESSPERMS)
618 + | (S_ISDIR(fst.st_mode) ? 0700 : 0600);
619 + if (fst.st_mode != mode)
620 + do_chmod(fname, mode);
621 + if (!IS_DEVICE(fst.st_mode) && !IS_SPECIAL(fst.st_mode))
622 + fst.st_rdev = 0; /* just in case */
624 + if (mode == fmode && fst.st_rdev == rdev
625 + && fst.st_uid == F_UID(file) && fst.st_gid == F_GID(file)) {
626 + /* xst.st_mode will be 0 if there's no current stat xattr */
627 + if (xst.st_mode && sys_lremovexattr(fname, XSTAT_ATTR) < 0) {
628 + rsyserr(FERROR, errno,
629 + "delete of stat xattr failed for %s",
630 + full_fname(fname));
636 + if (xst.st_mode != fmode || xst.st_rdev != rdev
637 + || xst.st_uid != F_UID(file) || xst.st_gid != F_GID(file)) {
639 + int len = snprintf(buf, sizeof buf, "%o %u,%u %u:%u",
640 + to_wire_mode(fmode),
641 + (int)major(rdev), (int)minor(rdev),
642 + (int)F_UID(file), (int)F_GID(file));
643 + if (sys_lsetxattr(fname, XSTAT_ATTR, buf, len) < 0) {
644 + if (errno == EPERM && S_ISLNK(fst.st_mode))
646 + rsyserr(FERROR, errno,
647 + "failed to write xattr %s for %s",
648 + XSTAT_ATTR, full_fname(fname));
656 +int x_stat(const char *fname, STRUCT_STAT *fst, STRUCT_STAT *xst)
658 + int ret = do_stat(fname, fst);
659 + if ((ret < 0 || get_stat_xattr(fname, -1, fst, xst) < 0) && xst)
664 +int x_lstat(const char *fname, STRUCT_STAT *fst, STRUCT_STAT *xst)
666 + int ret = do_lstat(fname, fst);
667 + if ((ret < 0 || get_stat_xattr(fname, -1, fst, xst) < 0) && xst)
672 +int x_fstat(int fd, STRUCT_STAT *fst, STRUCT_STAT *xst)
674 + int ret = do_fstat(fd, fst);
675 + if ((ret < 0 || get_stat_xattr(NULL, fd, fst, xst) < 0) && xst)
680 #endif /* SUPPORT_XATTRS */