The branch, master has been updated
via 43f70b96 The latest NEWS.
via b7231c7d Some extra file-list safety checks.
via 15c34f0a A few more minor doc tweaks.
from d1e42ffa A few minor fixes.
https://git.samba.org/?p=rsync.git;a=shortlog;h=master
- Log -----------------------------------------------------------------
commit 43f70b961e92d88387fecd3c7f6dbefc044ce4a3
Author: Wayne Davison <wa...@opencoder.net>
Date: Sun Jul 31 16:59:52 2022 -0700
The latest NEWS.
commit b7231c7d02cfb65d291af74ff66e7d8c507ee871
Author: Wayne Davison <wa...@opencoder.net>
Date: Sun Jul 31 16:55:34 2022 -0700
Some extra file-list safety checks.
commit 15c34f0a8c76e250f5487997849ab31e40e556e9
Author: Wayne Davison <wa...@opencoder.net>
Date: Mon Jul 11 13:31:30 2022 -0700
A few more minor doc tweaks.
-----------------------------------------------------------------------
Summary of changes:
NEWS.md | 27 ++++++++++++-
exclude.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
flist.c | 17 +++++++-
io.c | 4 ++
main.c | 7 +++-
receiver.c | 11 ++++--
rsync.1.md | 57 ++++++++++++++++++++++-----
7 files changed, 235 insertions(+), 18 deletions(-)
Changeset truncated at 500 lines:
diff --git a/NEWS.md b/NEWS.md
index ecaac28c..4cb98a63 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -2,9 +2,34 @@
## Changes in this version:
+### SECURITY FIXES:
+
+- Added some file-list safety checking that helps to ensure that a rogue
+ sending rsync can't add unrequested top-level names and/or include recursive
+ names that should have been excluded by the sender. This extra safety check
+ only requires the client side rsync to be udateed. When dealing with an
+ untrusted sending host using an older rsync, it is safest to copy into a
+ dedicated destination directory for the remote content (i.e. don't copy into
+ a destination directory that contains files that aren't from the remote
+ host unless you trust the remote host). Fixes CVE-2022-29154.
+
### BUG FIXES:
-- ...
+- Fixed the configure check for signed char that was causing a host that
+ defaults to unsigned characters to generate bogus rolling checksums. This
+ made rsync send mostly literal data for a copy instead of finding matching
+ data in the receiver's basis file.
+
+### PACKAGING RELATED:
+
+- The build date that goes into the manpages is now based on the developer's
+ release date, not on the build's local-timezone interpretation of the date.
+
+### DEVELOPER RELATED:
+
+- Configure now looks for the bsd/string.h include file in order to fix the
+ build on a host that has strlcpy() in the main libc but not defined in the
+ main string.h file.
------------------------------------------------------------------------------
diff --git a/exclude.c b/exclude.c
index 39073a0c..b670c8ba 100644
--- a/exclude.c
+++ b/exclude.c
@@ -27,16 +27,22 @@ extern int am_server;
extern int am_sender;
extern int eol_nulls;
extern int io_error;
+extern int xfer_dirs;
+extern int recurse;
extern int local_server;
extern int prune_empty_dirs;
extern int ignore_perishable;
+extern int old_style_args;
+extern int relative_paths;
extern int delete_mode;
extern int delete_excluded;
extern int cvs_exclude;
extern int sanitize_paths;
extern int protocol_version;
+extern int list_only;
extern int module_id;
+extern char *filesfrom_host;
extern char curr_dir[MAXPATHLEN];
extern unsigned int curr_dir_len;
extern unsigned int module_dirlen;
@@ -44,8 +50,10 @@ extern unsigned int module_dirlen;
filter_rule_list filter_list = { .debug_type = "" };
filter_rule_list cvs_filter_list = { .debug_type = " [global CVS]" };
filter_rule_list daemon_filter_list = { .debug_type = " [daemon]" };
+filter_rule_list implied_filter_list = { .debug_type = " [implied]" };
int saw_xattr_filter = 0;
+int trust_sender_filter = 0;
/* Need room enough for ":MODS " prefix plus some room to grow. */
#define MAX_RULE_PREFIX (16)
@@ -292,6 +300,125 @@ static void add_rule(filter_rule_list *listp, const char
*pat, unsigned int pat_
}
}
+/* Each arg the client sends to the remote sender turns into an implied include
+ * that the receiver uses to validate the file list from the sender. */
+void add_implied_include(const char *arg)
+{
+ filter_rule *rule;
+ int arg_len, saw_wild = 0, backslash_cnt = 0;
+ int slash_cnt = 1; /* We know we're adding a leading slash. */
+ const char *cp;
+ char *p;
+ if (old_style_args || list_only || filesfrom_host != NULL)
+ return;
+ if (relative_paths) {
+ cp = strstr(arg, "/./");
+ if (cp)
+ arg = cp+3;
+ } else {
+ if ((cp = strrchr(arg, '/')) != NULL)
+ arg = cp + 1;
+ }
+ arg_len = strlen(arg);
+ if (arg_len) {
+ if (strpbrk(arg, "*[?")) {
+ /* We need to add room to escape backslashes if
wildcard chars are present. */
+ cp = arg;
+ while ((cp = strchr(cp, '\\')) != NULL) {
+ arg_len++;
+ cp++;
+ }
+ saw_wild = 1;
+ }
+ arg_len++; /* Leave room for the prefixed slash */
+ rule = new0(filter_rule);
+ if (!implied_filter_list.head)
+ implied_filter_list.head = implied_filter_list.tail =
rule;
+ else {
+ rule->next = implied_filter_list.head;
+ implied_filter_list.head = rule;
+ }
+ rule->rflags = FILTRULE_INCLUDE + (saw_wild ? FILTRULE_WILD :
0);
+ p = rule->pattern = new_array(char, arg_len + 1);
+ *p++ = '/';
+ cp = arg;
+ while (*cp) {
+ switch (*cp) {
+ case '\\':
+ backslash_cnt++;
+ if (saw_wild)
+ *p++ = '\\';
+ *p++ = *cp++;
+ break;
+ case '/':
+ if (p[-1] == '/') /* This is safe because of
the initial slash. */
+ break;
+ if (relative_paths) {
+ filter_rule const *ent;
+ int found = 0;
+ *p = '\0';
+ for (ent = implied_filter_list.head;
ent; ent = ent->next) {
+ if (ent != rule &&
strcmp(ent->pattern, rule->pattern) == 0)
+ found = 1;
+ }
+ if (!found) {
+ filter_rule *R_rule =
new0(filter_rule);
+ R_rule->rflags =
FILTRULE_INCLUDE + (saw_wild ? FILTRULE_WILD : 0);
+ R_rule->pattern =
strdup(rule->pattern);
+ R_rule->u.slash_cnt = slash_cnt;
+ R_rule->next =
implied_filter_list.head;
+ implied_filter_list.head =
R_rule;
+ }
+ }
+ slash_cnt++;
+ *p++ = *cp++;
+ break;
+ default:
+ *p++ = *cp++;
+ break;
+ }
+ }
+ *p = '\0';
+ rule->u.slash_cnt = slash_cnt;
+ arg = (const char *)rule->pattern;
+ }
+
+ if (recurse || xfer_dirs) {
+ /* Now create a rule with an added "/" & "**" or "*" at the end
*/
+ rule = new0(filter_rule);
+ if (recurse)
+ rule->rflags = FILTRULE_INCLUDE | FILTRULE_WILD |
FILTRULE_WILD2;
+ else
+ rule->rflags = FILTRULE_INCLUDE | FILTRULE_WILD;
+ /* A +4 in the len leaves enough room for / * * \0 or / * \0 \0
*/
+ if (!saw_wild && backslash_cnt) {
+ /* We are appending a wildcard, so now the backslashes
need to be escaped. */
+ p = rule->pattern = new_array(char, arg_len +
backslash_cnt + 3 + 1);
+ cp = arg;
+ while (*cp) {
+ if (*cp == '\\')
+ *p++ = '\\';
+ *p++ = *cp++;
+ }
+ } else {
+ p = rule->pattern = new_array(char, arg_len + 3 + 1);
+ if (arg_len) {
+ memcpy(p, arg, arg_len);
+ p += arg_len;
+ }
+ }
+ if (p[-1] != '/')
+ *p++ = '/';
+ *p++ = '*';
+ if (recurse)
+ *p++ = '*';
+ *p = '\0';
+ rule->u.slash_cnt = slash_cnt + 1;
+ rule->next = implied_filter_list.head;
+ implied_filter_list.head = rule;
+ }
+}
+
/* This frees any non-inherited items, leaving just inherited items on the
list. */
static void pop_filter_list(filter_rule_list *listp)
{
@@ -718,7 +845,7 @@ static void report_filter_result(enum logcode code, char
const *name,
: name_flags & NAME_IS_DIR ? "directory"
: "file";
rprintf(code, "[%s] %sing %s %s because of pattern %s%s%s\n",
- w, actions[*w!='s'][!(ent->rflags & FILTRULE_INCLUDE)],
+ w, actions[*w=='g'][!(ent->rflags & FILTRULE_INCLUDE)],
t, name, ent->pattern,
ent->rflags & FILTRULE_DIRECTORY ? "/" : "", type);
}
@@ -890,6 +1017,7 @@ static filter_rule *parse_rule_tok(const char
**rulestr_ptr,
}
switch (ch) {
case ':':
+ trust_sender_filter = 1;
rule->rflags |= FILTRULE_PERDIR_MERGE
| FILTRULE_FINISH_SETUP;
/* FALL THROUGH */
diff --git a/flist.c b/flist.c
index 1ba306bc..0e6bf782 100644
--- a/flist.c
+++ b/flist.c
@@ -73,6 +73,7 @@ extern int need_unsorted_flist;
extern int sender_symlink_iconv;
extern int output_needs_newline;
extern int sender_keeps_checksum;
+extern int trust_sender_filter;
extern int unsort_ndx;
extern uid_t our_uid;
extern struct stats stats;
@@ -83,8 +84,7 @@ extern char curr_dir[MAXPATHLEN];
extern struct chmod_mode_struct *chmod_modes;
-extern filter_rule_list filter_list;
-extern filter_rule_list daemon_filter_list;
+extern filter_rule_list filter_list, implied_filter_list, daemon_filter_list;
#ifdef ICONV_OPTION
extern int filesfrom_convert;
@@ -986,6 +986,19 @@ static struct file_struct *recv_file_entry(int f, struct
file_list *flist, int x
exit_cleanup(RERR_UNSUPPORTED);
}
+ if (*thisname != '.' || thisname[1] != '\0') {
+ int filt_flags = S_ISDIR(mode) ? NAME_IS_DIR : NAME_IS_FILE;
+ if (!trust_sender_filter /* a per-dir filter rule means we must
trust the sender's filtering */
+ && filter_list.head && check_filter(&filter_list, FINFO,
thisname, filt_flags) < 0) {
+ rprintf(FERROR, "ERROR: rejecting excluded file-list
name: %s\n", thisname);
+ exit_cleanup(RERR_PROTOCOL);
+ }
+ if (implied_filter_list.head &&
check_filter(&implied_filter_list, FINFO, thisname, filt_flags) <= 0) {
+ rprintf(FERROR, "ERROR: rejecting unrequested file-list
name: %s\n", thisname);
+ exit_cleanup(RERR_PROTOCOL);
+ }
+ }
+
if (inc_recurse && S_ISDIR(mode)) {
if (one_file_system) {
/* Room to save the dir's device for -x */
diff --git a/io.c b/io.c
index cf94cee7..a6e3ed30 100644
--- a/io.c
+++ b/io.c
@@ -419,6 +419,7 @@ static void forward_filesfrom_data(void)
while (s != eob) {
if (*s++ == '\0') {
ff_xb.len = s - sob - 1;
+ add_implied_include(sob);
if (iconvbufs(ic_send, &ff_xb, &iobuf.out,
flags) < 0)
exit_cleanup(RERR_PROTOCOL); /*
impossible? */
write_buf(iobuf.out_fd, s-1, 1); /* Send the
'\0'. */
@@ -450,9 +451,12 @@ static void forward_filesfrom_data(void)
char *f = ff_xb.buf + ff_xb.pos;
char *t = ff_xb.buf;
char *eob = f + len;
+ char *cur = t;
/* Eliminate any multi-'\0' runs. */
while (f != eob) {
if (!(*t++ = *f++)) {
+ add_implied_include(cur);
+ cur = t;
while (f != eob && *f == '\0')
f++;
}
diff --git a/main.c b/main.c
index 58920a2d..5a7fbdd7 100644
--- a/main.c
+++ b/main.c
@@ -89,6 +89,7 @@ extern int backup_dir_len;
extern int basis_dir_cnt;
extern int default_af_hint;
extern int stdout_format_has_i;
+extern int trust_sender_filter;
extern struct stats stats;
extern char *stdout_format;
extern char *logfile_format;
@@ -104,7 +105,7 @@ extern char curr_dir[MAXPATHLEN];
extern char backup_dir_buf[MAXPATHLEN];
extern char *basis_dir[MAX_BASIS_DIRS+1];
extern struct file_list *first_flist;
-extern filter_rule_list daemon_filter_list;
+extern filter_rule_list daemon_filter_list, implied_filter_list;
uid_t our_uid;
gid_t our_gid;
@@ -635,6 +636,7 @@ static pid_t do_cmd(char *cmd, char *machine, char *user,
char **remote_argv, in
#ifdef ICONV_CONST
setup_iconv();
#endif
+ trust_sender_filter = 1;
} else if (local_server) {
/* If the user didn't request --[no-]whole-file, force
* it on, but only if we're not batch processing. */
@@ -1500,6 +1502,8 @@ static int start_client(int argc, char *argv[])
char *dummy_host;
int dummy_port = rsync_port;
int i;
+ if (filesfrom_fd < 0)
+ add_implied_include(remote_argv[0]);
/* For remote source, any extra source args must have either
* the same hostname or an empty hostname. */
for (i = 1; i < remote_argc; i++) {
@@ -1523,6 +1527,7 @@ static int start_client(int argc, char *argv[])
if (!rsync_port && !*arg) /* Turn an empty arg into a
dot dir. */
arg = ".";
remote_argv[i] = arg;
+ add_implied_include(arg);
}
}
diff --git a/receiver.c b/receiver.c
index b3a69da0..93cf8efd 100644
--- a/receiver.c
+++ b/receiver.c
@@ -593,10 +593,13 @@ int recv_files(int f_in, int f_out, char *local_name)
if (DEBUG_GTE(RECV, 1))
rprintf(FINFO, "recv_files(%s)\n", fname);
- if (daemon_filter_list.head && (*fname != '.' || fname[1] !=
'\0')
- && check_filter(&daemon_filter_list, FLOG, fname, 0) < 0) {
- rprintf(FERROR, "attempt to hack rsync failed.\n");
- exit_cleanup(RERR_PROTOCOL);
+ if (daemon_filter_list.head && (*fname != '.' || fname[1] !=
'\0')) {
+ int filt_flags = S_ISDIR(file->mode) ? NAME_IS_DIR :
NAME_IS_FILE;
+ if (check_filter(&daemon_filter_list, FLOG, fname,
filt_flags) < 0) {
+ rprintf(FERROR, "ERROR: rejecting file transfer
request for daemon excluded file: %s\n",
+ fname);
+ exit_cleanup(RERR_PROTOCOL);
+ }
}
#ifdef SUPPORT_XATTRS
diff --git a/rsync.1.md b/rsync.1.md
index 1ab014f1..576dd90b 100644
--- a/rsync.1.md
+++ b/rsync.1.md
@@ -167,6 +167,33 @@ separate the files into different rsync calls, or consider
using
[`--delay-updates`](#opt) (which doesn't affect the sorted transfer order, but
does make the final file-updating phase happen much more rapidly).
+## MULTI-HOST SECURITY
+
+Rsync takes steps to ensure that the file requests that are shared in a
+transfer are protected against various security issues. Most of the potential
+problems arise on the receiving side where rsync takes steps to ensure that the
+list of files being transferred remains within the bounds of what was
+requested.
+
+Toward this end, rsync 3.1.2 and later have aborted when a file list contains
+an absolute or relative path that tries to escape out of the top of the
+transfer. Also, beginning with version 3.2.5, rsync does two more safety
+checks of the file list to (1) ensure that no extra source arguments were added
+into the transfer other than those that the client requested and (2) ensure
+that the file list obeys the exclude rules that we sent to the sender.
+
+For those that don't yet have a 3.2.5 client rsync, it is safest to do a copy
+into a dedicated destination directory for the remote files rather than
+requesting the remote content get mixed in with other local content. For
+example, doing an rsync copy into your home directory is potentially unsafe on
+an older rsync if the remote rsync is being controlled by a bad actor:
+
+> rsync -aiv host1:dir1 ~
+
+A safer command would be:
+
+> rsync -aiv host1:dir1 ~/host1-files
+
## ADVANCED USAGE
The syntax for requesting multiple files from a remote host is done by
@@ -187,7 +214,7 @@ Starting in 3.2.4, filenames are passed to a remote shell
in such a way as to
preserve the characters you give it. Thus, if you ask for a file with spaces
in the name, that's what the remote rsync looks for:
-> rsync -aiv host:'a simple file.pdf' /dest/
+> rsync -aiv host:'a simple file.pdf' /dest/
If you use scripts that have been written to manually apply extra quoting to
the remote rsync args (or to require remote arg splitting), you can ask rsync
@@ -2343,6 +2370,12 @@ option name from the pathname using a space if you want
the shell to expand it.
behavior. The environment is always overridden by manually specified
positive or negative options (the negative is `--no-old-args`).
+ Note that this option also disables the extra safety check added in 3.2.5
+ that ensures that a remote sender isn't including extra top-level items in
+ the file-list that you didn't request. This side-effect is necessary
+ because we can't know for sure what names to expect when the remote shell
+ is interpreting the args.
+
This option conflicts with the [`--protect-args`](#opt) option.
0. `--protect-args`, `-s`
@@ -3795,7 +3828,7 @@ also warn if a filter rule has trailing whitespace, since
an exclude of "foo "
(with a trailing space) will not exclude a file named "foo".
Exclude and include rules can specify wildcard [PATTERN MATCHING RULES](#)
-(similar to shell wilcards) that allow you to match things like a file suffix
+(similar to shell wildcards) that allow you to match things like a file suffix
or a portion of a filename.
A rule can be limited to only affecting a directory by putting a trailing slash
@@ -3837,7 +3870,8 @@ it contains:
### FILTER RULES WHEN DELETING
-By default a filter rule affects both the sender (as it creates its file list)
+By default the include & exclude filter rules affect both the sender
+(as it creates its file list)
and the receiver (as it creates its file lists for calculating deletions). If
no delete option is in effect, the receiver skips creating the delete-related
file lists. This two-sided default can be manually overridden so that you are
@@ -3846,8 +3880,8 @@ RULES IN DEPTH](#) section.
When deleting, an exclude protects a file from being removed on the receiving
side while an include overrides that protection (putting the file at risk of
-deletion). The default is for a file to be at risk (its safety depends on it
-matching a corresponding file from the sender).
+deletion). The default is for a file to be at risk -- its safety depends on it
+matching a corresponding file from the sender.
An example of the two-sided exclude effect can be illustrated by the copying of
a C development directory between 2 systems. When doing a touch-up copy, you
@@ -3893,8 +3927,13 @@ Here are the available rule prefixes:
`hide` and a `protect`.
0. `include, '+'` specifies an include pattern that (by default) is both a
`show` and a `risk`.
-0. `merge, '.'` specifies a merge-file to read for more rules.
-0. `dir-merge, ':'` specifies a per-directory merge-file.
+0. `merge, '.'` specifies a merge-file on the client side to read for more
+ rules.
+0. `dir-merge, ':'` specifies a per-directory merge-file. Using this kind of
+ filter rule requires that you trust the sending side's filter checking, and
+ thus it disables the receiver's verification of the file-list names against
+ the filter rules (since only the sender can know for sure if it obeyed all
+ the filter rules when some are per-dir merged from the sender's files).
0. `hide, 'H'` specifies a pattern for hiding files from the transfer.
Equivalent to a sender-only exclude, so `-f'H foo'` could also be specified
as `-f'-s foo'`.
@@ -3957,7 +3996,7 @@ checking if the pattern contains one of these three
wildcard characters: '`*`',
must match one character.
- a trailing `***` in the pattern is a shorthand that allows you to match a
directory and all its contents using a single rule. For example, specifying
- "`dir_name/***`" will match both the "dir_name" directory (as if "dir_name/"
+ "`dir_name/***`" will match both the "dir_name" directory (as if
"`dir_name/`"
had been specified) and everything in the directory (as if "`dir_name/**`"
had been specified).
- a backslash can be used to escape a wildcard character, but it is only
@@ -4284,7 +4323,7 @@ Given that the files are still in the sender's file list,
the
[`--prune-empty-dirs`](#opt) option will not judge a directory as being empty
even if it contains only files that the transfer rules omitted.
-Similarly, a transfer rule does not have any extra affect on which files are
+Similarly, a transfer rule does not have any extra effect on which files are
deleted on the receiving side, so setting a maximum file size for the transfer
does not prevent big files from being deleted.
--
The rsync repository.
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