Add the ability to negate matches for the daemon's "refuse options".

3 files changed, 190 insertions, 81 deletions

diff --git a/NEWS b/NEWS
index 23b7f034..d29ea3c4 100644
--- a/NEWS
+++ b/NEWS
@@ -48,6 +48,9 @@ Changes since 3.1.3:
       script. Its value is the user-specified port number (set via --port or an
       rsync:// URL) or 0 if the user didn't override the port.
 
+    - Added negated matching to the daemon's "refuse options" setting by using
+      match strings that start with a "!" (such as "!compress*").
+
     - Added a status output based on a signal (via both SIGINFO & SIGVTALRM).
 
     - Added a --copy-as=USER option to give some extra security to root-run
diff --git a/options.c b/options.c
index a6693006..ebf31a60 100644
--- a/options.c
+++ b/options.c
@@ -1143,75 +1143,145 @@ void option_error(void)
 }
 
 
+static void set_one_refuse_option(int negated, const char *ref, const struct poptOption *list_end)
+{
+	struct poptOption *op;
+	char shortName[2];
+	int is_wild = strpbrk(ref, "*?[") != NULL;
+	int found_match = 0;
+
+	shortName[1] = '\0';
+
+	if (strcmp("a", ref) == 0 || strcmp("archive", ref) == 0) {
+		ref = "[ardlptgoD]";
+		is_wild = 1;
+	}
+
+	for (op = long_options; op != list_end; op++) {
+		*shortName = op->shortName;
+		if ((op->longName && wildmatch(ref, op->longName))
+		 || (*shortName && wildmatch(ref, shortName))) {
+			if (*op->descrip == 'a' || *op->descrip == 'r')
+				op->descrip = negated ? "accepted" : "refused";
+			else if (!is_wild)
+				op->descrip = negated ? "ACCEPTED" : "REFUSED";
+			found_match = 1;
+			if (!is_wild)
+				break;
+		}
+	}
+
+	if (!found_match)
+		rprintf(FLOG, "No match for refuse-options string \"%s\"\n", ref);
+}
+
+
 /**
  * Tweak the option table to disable all options that the rsyncd.conf
  * file has told us to refuse.
  **/
-static void set_refuse_options(char *bp)
+static void set_refuse_options(void)
 {
-	struct poptOption *op;
-	char *cp, shortname[2];
-	int is_wild, found_match;
+	struct poptOption *op, *list_end = NULL;
+	char *cp, *ref = lp_refuse_options(module_id);
+	int negated;
 
-	shortname[1] = '\0';
+	if (!ref)
+		ref = "";
 
-	while (1) {
-		while (*bp == ' ') bp++;
-		if (!*bp)
+	if (!*ref && !am_daemon) /* A simple optimization */
+		return;
+
+	/* We abuse the descrip field in poptOption to make it easy to flag which options
+	 * are refused (since we don't use it otherwise).  Start by marking all options
+	 * as accepted except for some that are marked as ACCEPTED (non-wild-matched). */
+	for (op = long_options; ; op++) {
+		const char *longName = op->longName ? op->longName : "";
+		if (!op->longName && !op->shortName) {
+			list_end = op;
 			break;
-		if ((cp = strchr(bp, ' ')) != NULL)
-			*cp= '\0';
-		is_wild = strpbrk(bp, "*?[") != NULL;
-		found_match = 0;
-		for (op = long_options; ; op++) {
-			*shortname = op->shortName;
-			if (!op->longName && !*shortname)
-				break;
-			if ((op->longName && wildmatch(bp, op->longName))
-			    || (*shortname && wildmatch(bp, shortname))) {
-				if (op->argInfo == POPT_ARG_VAL)
-					op->argInfo = POPT_ARG_NONE;
-				op->val = (op - long_options) + OPT_REFUSED_BASE;
-				found_match = 1;
-				/* These flags are set to let us easily check
-				 * an implied option later in the code. */
-				switch (*shortname) {
-				case 'r': case 'd': case 'l': case 'p':
-				case 't': case 'g': case 'o': case 'D':
-					refused_archive_part = op->val;
-					break;
-				case 'z':
-					refused_compress = op->val;
-					break;
-				case '\0':
-					if (wildmatch("delete", op->longName))
-						refused_delete = op->val;
-					else if (wildmatch("delete-before", op->longName))
-						refused_delete_before = op->val;
-					else if (wildmatch("delete-during", op->longName))
-						refused_delete_during = op->val;
-					else if (wildmatch("partial", op->longName))
-						refused_partial = op->val;
-					else if (wildmatch("progress", op->longName))
-						refused_progress = op->val;
-					else if (wildmatch("inplace", op->longName))
-						refused_inplace = op->val;
-					else if (wildmatch("no-iconv", op->longName))
-						refused_no_iconv = op->val;
-					break;
-				}
-				if (!is_wild)
-					break;
-			}
-		}
-		if (!found_match) {
-			rprintf(FLOG, "No match for refuse-options string \"%s\"\n",
-				bp);
 		}
+		/* These options are protected from wild-card matching, but the user is free to
+		 * shoot themselves in the foot if they specify the option explicitly. */
+		if (op->shortName == 'e'
+		 || op->shortName == '0' /* --from0 just modifies --files-from, so refuse that instead (or not) */
+		 || op->shortName == 's' /* --protect-args is always OK */
+		 || op->shortName == 'n' /* --dry-run is always OK */
+		 || strcmp("server", longName) == 0
+		 || strcmp("sender", longName) == 0
+		 || strcmp("iconv", longName) == 0
+		 || strcmp("no-iconv", longName) == 0
+		 || strcmp("checksum-seed", longName) == 0
+		 || strcmp("write-devices", longName) == 0 /* disable wild-match (it gets refused below) */
+		 || strcmp("log-format", longName) == 0)
+			op->descrip = "ACCEPTED";
+		else
+			op->descrip = "accepted";
+	}
+	assert(list_end != NULL);
+
+	if (am_daemon) /* Refused by default, but can be accepted via "!write-devices" */
+		set_one_refuse_option(0, "write-devices", list_end);
+
+	while (1) {
+		while (*ref == ' ') ref++;
+		if (!*ref)
+			break;
+		if ((cp = strchr(ref, ' ')) != NULL)
+			*cp = '\0';
+		negated = *ref == '!';
+		if (negated && ref[1])
+			ref++;
+		set_one_refuse_option(negated, ref, list_end);
 		if (!cp)
 			break;
 		*cp = ' ';
-		bp = cp + 1;
+		ref = cp + 1;
+	}
+
+	if (am_daemon) {
+#ifdef ICONV_OPTION
+		if (!*lp_charset(module_id))
+			set_one_refuse_option(0, "iconv", list_end);
+#endif
+		set_one_refuse_option(0, "log-file", list_end);
+	}
+
+	/* Now we use the descrip values to actually mark the options for refusal. */
+	for (op = long_options; op != list_end; op++) {
+		int refused = *op->descrip == 'r' || *op->descrip == 'R';
+		op->descrip = NULL;
+		if (!refused)
+			continue;
+		if (op->argInfo == POPT_ARG_VAL)
+			op->argInfo = POPT_ARG_NONE;
+		op->val = (op - long_options) + OPT_REFUSED_BASE;
+		/* The following flags are set to let us easily check an implied option later in the code. */
+		switch (op->shortName) {
+		case 'r': case 'd': case 'l': case 'p':
+		case 't': case 'g': case 'o': case 'D':
+			refused_archive_part = op->val;
+			break;
+		case 'z':
+			refused_compress = op->val;
+			break;
+		case '\0':
+			if (strcmp("delete", op->longName) == 0)
+				refused_delete = op->val;
+			else if (strcmp("delete-before", op->longName) == 0)
+				refused_delete_before = op->val;
+			else if (strcmp("delete-during", op->longName) == 0)
+				refused_delete_during = op->val;
+			else if (strcmp("partial", op->longName) == 0)
+				refused_partial = op->val;
+			else if (strcmp("progress", op->longName) == 0)
+				refused_progress = op->val;
+			else if (strcmp("inplace", op->longName) == 0)
+				refused_inplace = op->val;
+			else if (strcmp("no-iconv", op->longName) == 0)
+				refused_no_iconv = op->val;
+			break;
+		}
 	}
 }
 
@@ -1327,7 +1397,6 @@ static void popt_unalias(poptContext con, const char *opt)
 int parse_arguments(int *argc_p, const char ***argv_p)
 {
 	static poptContext pc;
-	char *ref = lp_refuse_options(module_id);
 	const char *arg, **argv = *argv_p;
 	int argc = *argc_p;
 	int opt;
@@ -1337,16 +1406,8 @@ int parse_arguments(int *argc_p, const char ***argv_p)
 		strlcpy(err_buf, "argc is zero!\n", sizeof err_buf);
 		return 0;
 	}
-	if (ref && *ref)
-		set_refuse_options(ref);
-	if (am_daemon) {
-		set_refuse_options("log-file*");
-#ifdef ICONV_OPTION
-		if (!*lp_charset(module_id))
-			set_refuse_options("iconv");
-#endif
-		set_refuse_options("write-devices");
-	}
+
+	set_refuse_options();
 
 #ifdef ICONV_OPTION
 	if (!am_daemon && protect_args <= 0 && (arg = getenv("RSYNC_ICONV")) != NULL && *arg)
@@ -1555,7 +1616,7 @@ int parse_arguments(int *argc_p, const char ***argv_p)
 
 		case 'U':
 			if (++preserve_atimes > 1)
-			    open_noatime = 1;
+				open_noatime = 1;
 			break;
 
 		case 'v':
diff --git a/rsyncd.conf.yo b/rsyncd.conf.yo
index 8f004ae6..c3bc3dd1 100644
--- a/rsyncd.conf.yo
+++ b/rsyncd.conf.yo
@@ -735,28 +735,73 @@ is specified in seconds. A value of zero means no timeout and is the
 default. A good choice for anonymous rsync daemons may be 600 (giving
 a 10 minute timeout).
 
-dit(bf(refuse options)) This parameter allows you to
-specify a space-separated list of rsync command line options that will
-be refused by your rsync daemon.
+dit(bf(refuse options)) This parameter allows you to specify a space-separated
+list of rsync command line options that will be refused by your rsync daemon.
 You may specify the full option name, its one-letter abbreviation, or a
-wild-card string that matches multiple options.
+wild-card string that matches multiple options. Beginning in 3.2.0, you can
+also negate a match term by starting it with a "!".
+
+When an option is refused, the daemon prints an error message and exits.
+
 For example, this would refuse bf(--checksum) (bf(-c)) and all the various
 delete options:
 
-quote(tt(    refuse options = c delete))
+verb(    refuse options = c delete)
 
 The reason the above refuses all delete options is that the options imply
 bf(--delete), and implied options are refused just like explicit options.
+
+The use of a negated match allows you to fine-tune your refusals after a
+wild-card, such as this:
+
+verb(    refuse options = delete-* !delete-during)
+
+Negated matching can also turn your list of refused options into a list of
+accepted options. To do this, begin the list with a "*" (to refuse all options)
+and then specify one or more negated matches to allow.  For example:
+
+verb(    refuse options = * !a !v !compress*)
+
+Don't worry that the "*" will refuse certain vital options such as
+bf(--server), bf(--no-iconv), bf(--protect-args), etc. These important options
+are not matched by a wild-card, so they must be overridden by their exact name.
+For instance, if you're forcing iconv transfers you could use something like
+this:
+
+verb(    refuse options = * no-iconv !a !v)
+
+As an additional aid (beginning in 3.2.0), refusing (or "!refusing") the "a" or
+"archive"  option also affects all the options that the bf(--archive) option
+implies (bf(-rdlptgoD)), but only if the option  is matched explicitly (not
+using a wildcard). If you want to do something tricky, you can use "archive*"
+to avoid this side-effect, but keep in mind that no normal rsync client ever
+sends the actual archive option to the server.
+
 As an additional safety feature, the refusal of "delete" also refuses
 bf(remove-source-files) when the daemon is the sender; if you want the latter
-without the former, instead refuse "delete-*" -- that refuses all the
-delete modes without affecting bf(--remove-source-files).
+without the former, instead refuse "delete-*" as that refuses all the delete
+modes without affecting bf(--remove-source-files). (Keep in mind that the
+client's bf(--delete) option typically enables bf(--delete-during).)
 
-When an option is refused, the daemon prints an error message and exits.
-To prevent all compression when serving files,
-you can use "dont compress = *" (see below)
-instead of "refuse options = compress" to avoid returning an error to a
-client that requests compression.
+When un-refusing delete options, you should either specify "!delete*" (to
+accept all delete options) or specify a limited set that includes "delete",
+such as:
+
+verb(    refuse options = * !a !delete !delete-during)
+
+... whereas this accepts any delete option except bf(--delete-after):
+
+verb(    refuse options = * !a !delete* delete-after)
+
+A note on refusing "compress" -- it is better to set the "dont compress" daemon
+option to "*" because that disables compression silently instead of returning
+an error that forces the client to remove the bf(-z) option.
+
+If you are un-refusing the compress option, you probably want to match
+"!compress*" so that you also allow the bf(--compress-level) option.
+
+Finally, the "write-devices" option is refused by default, but can be
+explicitly enabled with "!write-devices".
 
 dit(bf(dont compress)) This parameter allows you to select
 filenames based on wildcard patterns that should not be compressed