- Add a vendor patch that adds a new option "munge symlinks".

  Users running rsyncd daemon in certain non-default configuration
  (use_chroot = no) should consult http://rsync.samba.org/security.html
  and see, what munging symlinks can do for them.

Submitted by:	delphij
Approved by:	portmgr (hat)
Security:	CVE-2007-6199

2 files changed, 341 insertions, 1 deletions

diff --git a/net/rsync/Makefile b/net/rsync/Makefile
index 72116a66c790..581d631ca238 100644
--- a/net/rsync/Makefile
+++ b/net/rsync/Makefile
@@ -7,7 +7,7 @@
 
 PORTNAME=	rsync
 PORTVERSION=	2.6.9
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	net ipv6
 MASTER_SITES=	http://rsync.samba.org/ftp/%SUBDIR%/ \
 		ftp://ftp.samba.org/pub/%SUBDIR%/ \
diff --git a/net/rsync/files/patch-CVE-2007-6199 b/net/rsync/files/patch-CVE-2007-6199
new file mode 100644
index 000000000000..1fb58e02fe52
--- /dev/null
+++ b/net/rsync/files/patch-CVE-2007-6199
@@ -0,0 +1,340 @@
+--- rsync-2.6.9/clientserver.c	2006-10-23 17:36:42.000000000 -0700
++++ ./clientserver.c	2007-11-26 21:32:53.000000000 -0800
+@@ -55,6 +55,7 @@ extern struct filter_list_struct server_
+ char *auth_user;
+ int read_only = 0;
+ int module_id = -1;
++int munge_symlinks = 0;
+ struct chmod_mode_struct *daemon_chmod_modes;
+ 
+ /* Length of lp_path() string when in daemon mode & not chrooted, else 0. */
+@@ -524,6 +525,18 @@ static int rsync_module(int f_in, int f_
+ 		sanitize_paths = 1;
+ 	}
+ 
++	if ((munge_symlinks = lp_munge_symlinks(i)) < 0)
++		munge_symlinks = !use_chroot;
++	if (munge_symlinks) {
++		STRUCT_STAT st;
++		if (stat(SYMLINK_PREFIX, &st) == 0 && S_ISDIR(st.st_mode)) {
++			rprintf(FLOG, "Symlink munging is unsupported when a %s directory exists.\n",
++				SYMLINK_PREFIX);
++			io_printf(f_out, "@ERROR: daemon security issue -- contact admin\n", name);
++			exit_cleanup(RERR_UNSUPPORTED);
++		}
++	}
++
+ 	if (am_root) {
+ 		/* XXXX: You could argue that if the daemon is started
+ 		 * by a non-root user and they explicitly specify a
+--- rsync-2.6.9/flist.c	2006-10-13 18:17:36.000000000 -0700
++++ ./flist.c	2007-11-27 12:56:25.000000000 -0800
+@@ -53,6 +53,7 @@ extern int copy_links;
+ extern int copy_unsafe_links;
+ extern int protocol_version;
+ extern int sanitize_paths;
++extern int munge_symlinks;
+ extern struct stats stats;
+ extern struct file_list *the_file_list;
+ 
+@@ -174,6 +175,11 @@ static int readlink_stat(const char *pat
+ 			}
+ 			return do_stat(path, stp);
+ 		}
++		if (munge_symlinks && am_sender && llen > SYMLINK_PREFIX_LEN
++		 && strncmp(linkbuf, SYMLINK_PREFIX, SYMLINK_PREFIX_LEN) == 0) {
++			memmove(linkbuf, linkbuf + SYMLINK_PREFIX_LEN,
++				llen - SYMLINK_PREFIX_LEN + 1);
++		}
+ 	}
+ 	return 0;
+ #else
+@@ -591,6 +597,8 @@ static struct file_struct *receive_file_
+ 				linkname_len - 1);
+ 			overflow_exit("receive_file_entry");
+ 		}
++		if (munge_symlinks)
++			linkname_len += SYMLINK_PREFIX_LEN;
+ 	}
+ 	else
+ #endif
+@@ -658,10 +666,17 @@ static struct file_struct *receive_file_
+ #ifdef SUPPORT_LINKS
+ 	if (linkname_len) {
+ 		file->u.link = bp;
++		if (munge_symlinks) {
++			strlcpy(bp, SYMLINK_PREFIX, linkname_len);
++			bp += SYMLINK_PREFIX_LEN;
++			linkname_len -= SYMLINK_PREFIX_LEN;
++		}
+ 		read_sbuf(f, bp, linkname_len - 1);
+-		if (sanitize_paths)
++		if (sanitize_paths && !munge_symlinks) {
+ 			sanitize_path(bp, bp, "", lastdir_depth, NULL);
+-		bp += linkname_len;
++			bp += strlen(bp) + 1;
++		} else
++			bp += linkname_len;
+ 	}
+ #endif
+ 
+--- rsync-2.6.9/loadparm.c	2006-10-12 23:49:44.000000000 -0700
++++ ./loadparm.c	2007-11-26 11:46:46.000000000 -0800
+@@ -153,6 +153,7 @@ typedef struct
+ 	BOOL ignore_errors;
+ 	BOOL ignore_nonreadable;
+ 	BOOL list;
++	BOOL munge_symlinks;
+ 	BOOL read_only;
+ 	BOOL strict_modes;
+ 	BOOL transfer_logging;
+@@ -200,6 +201,7 @@ static service sDefault =
+  /* ignore_errors; */		False,
+  /* ignore_nonreadable; */	False,
+  /* list; */			True,
++ /* munge_symlinks; */		(BOOL)-1,
+  /* read_only; */		True,
+  /* strict_modes; */		True,
+  /* transfer_logging; */	False,
+@@ -313,6 +315,7 @@ static struct parm_struct parm_table[] =
+  {"log format",        P_STRING, P_LOCAL, &sDefault.log_format,        NULL,0},
+  {"max connections",   P_INTEGER,P_LOCAL, &sDefault.max_connections,   NULL,0},
+  {"max verbosity",     P_INTEGER,P_LOCAL, &sDefault.max_verbosity,     NULL,0},
++ {"munge symlinks",    P_BOOL,   P_LOCAL, &sDefault.munge_symlinks,    NULL,0},
+  {"name",              P_STRING, P_LOCAL, &sDefault.name,              NULL,0},
+  {"outgoing chmod",    P_STRING, P_LOCAL, &sDefault.outgoing_chmod,    NULL,0},
+  {"path",              P_PATH,   P_LOCAL, &sDefault.path,              NULL,0},
+@@ -415,6 +418,7 @@ FN_LOCAL_INTEGER(lp_timeout, timeout)
+ FN_LOCAL_BOOL(lp_ignore_errors, ignore_errors)
+ FN_LOCAL_BOOL(lp_ignore_nonreadable, ignore_nonreadable)
+ FN_LOCAL_BOOL(lp_list, list)
++FN_LOCAL_BOOL(lp_munge_symlinks, munge_symlinks)
+ FN_LOCAL_BOOL(lp_read_only, read_only)
+ FN_LOCAL_BOOL(lp_strict_modes, strict_modes)
+ FN_LOCAL_BOOL(lp_transfer_logging, transfer_logging)
+--- rsync-2.6.9/proto.h	2006-11-06 20:39:47.000000000 -0800
++++ ./proto.h	2007-11-27 13:15:23.000000000 -0800
+@@ -176,6 +176,7 @@ int lp_timeout(int );
+ BOOL lp_ignore_errors(int );
+ BOOL lp_ignore_nonreadable(int );
+ BOOL lp_list(int );
++BOOL lp_munge_symlinks(int );
+ BOOL lp_read_only(int );
+ BOOL lp_strict_modes(int );
+ BOOL lp_transfer_logging(int );
+--- rsync-2.6.9/rsync.h	2006-10-23 20:31:30.000000000 -0700
++++ ./rsync.h	2007-11-26 21:34:11.000000000 -0800
+@@ -33,6 +33,9 @@
+ #define DEFAULT_LOCK_FILE "/var/run/rsyncd.lock"
+ #define URL_PREFIX "rsync://"
+ 
++#define SYMLINK_PREFIX "/rsyncd-munged/"
++#define SYMLINK_PREFIX_LEN ((int)sizeof SYMLINK_PREFIX - 1)
++
+ #define BACKUP_SUFFIX "~"
+ 
+ /* a non-zero CHAR_OFFSET makes the rolling sum stronger, but is
+--- rsync-2.6.9/rsyncd.conf.5	2006-11-06 20:39:52.000000000 -0800
++++ ./rsyncd.conf.5	2007-11-27 13:15:23.000000000 -0800
+@@ -145,12 +145,15 @@ the advantage of extra protection agains
+ holes, but it has the disadvantages of requiring super-user privileges,
+ of not being able to follow symbolic links that are either absolute or outside
+ of the new root path, and of complicating the preservation of usernames and groups
+-(see below)\&.  When "use chroot" is false, for security reasons,
+-symlinks may only be relative paths pointing to other files within the root
+-path, and leading slashes are removed from most absolute paths (options
+-such as \fB\-\-backup\-dir\fP, \fB\-\-compare\-dest\fP, etc\&. interpret an absolute path as
+-rooted in the module\&'s "path" dir, just as if chroot was specified)\&.
+-The default for "use chroot" is true\&.
++(see below)\&.  When "use chroot" is false, rsync will: (1) munge symlinks by
++default for security reasons (see "munge symlinks" for a way to turn this
++off, but only if you trust your users), (2) substitute leading slashes in
++absolute paths with the module\&'s path (so that options such as
++\fB\-\-backup\-dir\fP, \fB\-\-compare\-dest\fP, etc\&. interpret an absolute path as
++rooted in the module\&'s "path" dir), and (3) trim "\&.\&." path elements from
++args if rsync believes they would escape the chroot\&.
++The default for "use chroot" is true, and is the safer choice (especially
++if the module is not read-only)\&.
+ .IP 
+ In order to preserve usernames and groupnames, rsync needs to be able to
+ use the standard library functions for looking up names and IDs (i\&.e\&.
+@@ -181,6 +184,41 @@ access to some of the excluded files ins
+ do this automatically, but you might as well specify both to be extra
+ sure)\&.
+ .IP 
++.IP "\fBmunge symlinks\fP"
++The "munge symlinks" option tells rsync to modify
++all incoming symlinks in a way that makes them unusable but recoverable
++(see below)\&.  This should help protect your files from user trickery when
++your daemon module is writable\&.  The default is disabled when "use chroot"
++is on and enabled when "use chroot" is off\&.
++.IP 
++If you disable this option on a daemon that is not read-only, there
++are tricks that a user can play with uploaded symlinks to access
++daemon-excluded items (if your module has any), and, if "use chroot"
++is off, rsync can even be tricked into showing or changing data that
++is outside the module\&'s path (as access-permissions allow)\&.
++.IP 
++The way rsync disables the use of symlinks is to prefix each one with
++the string "/rsyncd-munged/"\&.  This prevents the links from being used
++as long as that directory does not exist\&.  When this option is enabled,
++rsync will refuse to run if that path is a directory or a symlink to
++a directory\&.  When using the "munge symlinks" option in a chroot area,
++you should add this path to the exclude setting for the module so that
++the user can\&'t try to create it\&.
++.IP 
++Note:  rsync makes no attempt to verify that any pre-existing symlinks in
++the hierarchy are as safe as you want them to be\&.  If you setup an rsync
++daemon on a new area or locally add symlinks, you can manually protect your
++symlinks from being abused by prefixing "/rsyncd-munged/" to the start of
++every symlink\&'s value\&.  There is a perl script in the support directory
++of the source code named "munge-symlinks" that can be used to add or remove
++this prefix from your symlinks\&.
++.IP 
++When this option is disabled on a writable module and "use chroot" is off,
++incoming symlinks will be modified to drop a leading slash and to remove "\&.\&."
++path elements that rsync believes will allow a symlink to escape the module\&'s
++hierarchy\&.  There are tricky ways to work around this, though, so you had
++better trust your users if you choose this combination of options\&.
++.IP 
+ .IP "\fBmax connections\fP"
+ The "max connections" option allows you to
+ specify the maximum number of simultaneous connections you will allow\&.
+--- rsync-2.6.9/rsyncd.conf.yo	2006-11-06 20:39:47.000000000 -0800
++++ ./rsyncd.conf.yo	2007-11-27 13:14:07.000000000 -0800
+@@ -129,12 +129,15 @@ the advantage of extra protection agains
+ holes, but it has the disadvantages of requiring super-user privileges,
+ of not being able to follow symbolic links that are either absolute or outside
+ of the new root path, and of complicating the preservation of usernames and groups
+-(see below).  When "use chroot" is false, for security reasons,
+-symlinks may only be relative paths pointing to other files within the root
+-path, and leading slashes are removed from most absolute paths (options
+-such as bf(--backup-dir), bf(--compare-dest), etc. interpret an absolute path as
+-rooted in the module's "path" dir, just as if chroot was specified).
+-The default for "use chroot" is true.
++(see below).  When "use chroot" is false, rsync will: (1) munge symlinks by
++default for security reasons (see "munge symlinks" for a way to turn this
++off, but only if you trust your users), (2) substitute leading slashes in
++absolute paths with the module's path (so that options such as
++bf(--backup-dir), bf(--compare-dest), etc. interpret an absolute path as
++rooted in the module's "path" dir), and (3) trim ".." path elements from
++args if rsync believes they would escape the chroot.
++The default for "use chroot" is true, and is the safer choice (especially
++if the module is not read-only).
+ 
+ In order to preserve usernames and groupnames, rsync needs to be able to
+ use the standard library functions for looking up names and IDs (i.e.
+@@ -158,6 +161,40 @@ access to some of the excluded files ins
+ do this automatically, but you might as well specify both to be extra
+ sure).
+ 
++dit(bf(munge symlinks))  The "munge symlinks" option tells rsync to modify
++all incoming symlinks in a way that makes them unusable but recoverable
++(see below).  This should help protect your files from user trickery when
++your daemon module is writable.  The default is disabled when "use chroot"
++is on and enabled when "use chroot" is off.
++
++If you disable this option on a daemon that is not read-only, there
++are tricks that a user can play with uploaded symlinks to access
++daemon-excluded items (if your module has any), and, if "use chroot"
++is off, rsync can even be tricked into showing or changing data that
++is outside the module's path (as access-permissions allow).
++
++The way rsync disables the use of symlinks is to prefix each one with
++the string "/rsyncd-munged/".  This prevents the links from being used
++as long as that directory does not exist.  When this option is enabled,
++rsync will refuse to run if that path is a directory or a symlink to
++a directory.  When using the "munge symlinks" option in a chroot area,
++you should add this path to the exclude setting for the module so that
++the user can't try to create it.
++
++Note:  rsync makes no attempt to verify that any pre-existing symlinks in
++the hierarchy are as safe as you want them to be.  If you setup an rsync
++daemon on a new area or locally add symlinks, you can manually protect your
++symlinks from being abused by prefixing "/rsyncd-munged/" to the start of
++every symlink's value.  There is a perl script in the support directory
++of the source code named "munge-symlinks" that can be used to add or remove
++this prefix from your symlinks.
++
++When this option is disabled on a writable module and "use chroot" is off,
++incoming symlinks will be modified to drop a leading slash and to remove ".."
++path elements that rsync believes will allow a symlink to escape the module's
++hierarchy.  There are tricky ways to work around this, though, so you had
++better trust your users if you choose this combination of options.
++
+ dit(bf(max connections)) The "max connections" option allows you to
+ specify the maximum number of simultaneous connections you will allow.
+ Any clients connecting when the maximum has been reached will receive a
+--- rsync-2.6.9/support/munge-symlinks	1969-12-31 16:00:00.000000000 -0800
++++ ./support/munge-symlinks	2007-11-26 22:04:26.000000000 -0800
+@@ -0,0 +1,60 @@
++#!/usr/bin/perl
++# This script will either prefix all symlink values with the string
++# "/rsyncd-munged/" or remove that prefix.
++
++use strict;
++use Getopt::Long;
++
++my $SYMLINK_PREFIX = '/rsyncd-munged/';
++
++my $munge_opt;
++
++&GetOptions(
++    'munge' => sub { $munge_opt = 1 },
++    'unmunge' => sub { $munge_opt = 0 },
++    'all' => \( my $all_opt ),
++    'help|h' => \( my $help_opt ),
++) or &usage;
++
++&usage if $help_opt || !defined $munge_opt;
++
++my $munged_re = $all_opt ? qr/^($SYMLINK_PREFIX)+(?=.)/ : qr/^$SYMLINK_PREFIX(?=.)/;
++
++push(@ARGV, '.') unless @ARGV;
++
++open(PIPE, '-|', 'find', @ARGV, '-type', 'l') or die $!;
++
++while (<PIPE>) {
++    chomp;
++    my $lnk = readlink($_) or next;
++    if ($munge_opt) {
++	next if !$all_opt && $lnk =~ /$munged_re/;
++	$lnk =~ s/^/$SYMLINK_PREFIX/;
++    } else {
++	next unless $lnk =~ s/$munged_re//;
++    }
++    if (!unlink($_)) {
++	warn "Unable to unlink symlink: $_ ($!)\n";
++    } elsif (!symlink($lnk, $_)) {
++	warn "Unable to recreate symlink: $_ -> $lnk ($!)\n";
++    } else {
++	print "$_ -> $lnk\n";
++    }
++}
++
++close PIPE;
++exit;
++
++sub usage
++{
++    die <<EOT;
++Usage: munge-symlinks --munge|--unmunge [--all] [DIR|SYMLINK...]
++
++--munge      Add the $SYMLINK_PREFIX prefix to symlinks if not already
++             present, or always when combined with --all.
++--unmunge    Remove one $SYMLINK_PREFIX prefix from symlinks or all
++             such prefixes with --all.
++
++See the "munge symlinks" option in the rsyncd.conf manpage for more details.
++EOT
++}
+--- rsync-2.6.9/testsuite/rsync.fns	2006-05-30 11:26:17.000000000 -0700
++++ ./testsuite/rsync.fns	2007-11-26 11:49:35.000000000 -0800
+@@ -231,6 +231,7 @@ build_rsyncd_conf() {
+ 
+ pid file = $pidfile
+ use chroot = no
++munge symlinks = no
+ hosts allow = localhost 127.0.0.1 $hostname
+ log file = $logfile
+ log format = %i %h [%a] %m (%u) %l %f%L