- djm@cvs.openbsd.org 2005/06/06 11:20:36

     [auth.c auth.h misc.c misc.h ssh.c ssh_config.5 sshconnect.c]
     introduce a generic %foo expansion function. replace existing % expansion
     and add expansion to ControlPath; ok markus@

8 files changed, 119 insertions, 84 deletions

diff --git a/ChangeLog b/ChangeLog
index 71e7beea0..b439cbecd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,7 +3,10 @@
    - jaredy@cvs.openbsd.org 2005/06/07 13:25:23
      [progressmeter.c]
      catch SIGWINCH and resize progress meter accordingly; ok markus dtucker
-
+   - djm@cvs.openbsd.org 2005/06/06 11:20:36
+     [auth.c auth.h misc.c misc.h ssh.c ssh_config.5 sshconnect.c]
+     introduce a generic %foo expansion function. replace existing % expansion 
+     and add expansion to ControlPath; ok markus@
 
 20050609
  - (dtucker) [cipher.c openbsd-compat/Makefile.in
@@ -2699,4 +2702,4 @@
    - (djm) Trim deprecated options from INSTALL. Mention UsePAM
    - (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
 
-$Id: ChangeLog,v 1.3816 2005/06/16 03:18:04 djm Exp $
+$Id: ChangeLog,v 1.3817 2005/06/16 03:18:34 djm Exp $
diff --git a/auth.c b/auth.c
index 46b013137..68c2824fb 100644
--- a/auth.c
+++ b/auth.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: auth.c,v 1.58 2005/03/14 11:44:42 dtucker Exp $");
+RCSID("$OpenBSD: auth.c,v 1.59 2005/06/06 11:20:36 djm Exp $");
 
 #ifdef HAVE_LOGIN_H
 #include <login.h>
@@ -326,64 +326,41 @@ auth_root_allowed(char *method)
  *
  * This returns a buffer allocated by xmalloc.
  */
-char *
-expand_filename(const char *filename, struct passwd *pw)
+static char *
+expand_authorized_keys(const char *filename, struct passwd *pw)
 {
-        Buffer buffer;
-        char *file;
-        const char *cp;
+        char *file, *ret;
 
-        /*
-         * Build the filename string in the buffer by making the appropriate
-         * substitutions to the given file name.
-         */
-        buffer_init(&buffer);
-        for (cp = filename; *cp; cp++) {
-                if (cp[0] == '%' && cp[1] == '%') {
-                        buffer_append(&buffer, "%", 1);
-                        cp++;
-                        continue;
-                }
-                if (cp[0] == '%' && cp[1] == 'h') {
-                        buffer_append(&buffer, pw->pw_dir, strlen(pw->pw_dir));
-                        cp++;
-                        continue;
-                }
-                if (cp[0] == '%' && cp[1] == 'u') {
-                        buffer_append(&buffer, pw->pw_name,
-                            strlen(pw->pw_name));
-                        cp++;
-                        continue;
-                }
-                buffer_append(&buffer, cp, 1);
-        }
-        buffer_append(&buffer, "\0", 1);
+        file = percent_expand(filename, "h", pw->pw_dir,
+            "u", pw->pw_name, (char *)NULL);
 
         /*
          * Ensure that filename starts anchored. If not, be backward
          * compatible and prepend the '%h/'
          */
-        file = xmalloc(MAXPATHLEN);
-        cp = buffer_ptr(&buffer);
-        if (*cp != '/')
-                snprintf(file, MAXPATHLEN, "%s/%s", pw->pw_dir, cp);
-        else
-                strlcpy(file, cp, MAXPATHLEN);
+        if (*file == '/')
+                return (file);
+
+        ret = xmalloc(MAXPATHLEN);
+        if (strlcpy(ret, pw->pw_dir, MAXPATHLEN) >= MAXPATHLEN ||
+            strlcat(ret, "/", MAXPATHLEN) >= MAXPATHLEN ||
+            strlcat(ret, file, MAXPATHLEN) >= MAXPATHLEN)
+                fatal("expand_authorized_keys: path too long");
 
-        buffer_free(&buffer);
-        return file;
+        xfree(file);
+        return (ret);
 }
 
 char *
 authorized_keys_file(struct passwd *pw)
 {
-        return expand_filename(options.authorized_keys_file, pw);
+        return expand_authorized_keys(options.authorized_keys_file, pw);
 }
 
 char *
 authorized_keys_file2(struct passwd *pw)
 {
-        return expand_filename(options.authorized_keys_file2, pw);
+        return expand_authorized_keys(options.authorized_keys_file2, pw);
 }
 
 /* return ok if key exists in sysfile or userfile */
diff --git a/auth.h b/auth.h
index 471404e4e..bf47b9a64 100644
--- a/auth.h
+++ b/auth.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: auth.h,v 1.50 2004/05/23 23:59:53 dtucker Exp $       */
+/*      $OpenBSD: auth.h,v 1.51 2005/06/06 11:20:36 djm Exp $   */
 
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
@@ -163,7 +163,6 @@ char	*get_challenge(Authctxt *);
 int     verify_response(Authctxt *, const char *);
 void    abandon_challenge_response(Authctxt *);
 
-char    *expand_filename(const char *, struct passwd *);
 char    *authorized_keys_file(struct passwd *);
 char    *authorized_keys_file2(struct passwd *);
 
diff --git a/misc.c b/misc.c
index 4bc07a42a..fc094f874 100644
--- a/misc.c
+++ b/misc.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
+ * Copyright (c) 2005 Damien Miller.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -23,7 +24,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: misc.c,v 1.30 2005/04/09 04:32:54 djm Exp $");
+RCSID("$OpenBSD: misc.c,v 1.31 2005/06/06 11:20:36 djm Exp $");
 
 #include "misc.h"
 #include "log.h"
@@ -421,6 +422,68 @@ tilde_expand_filename(const char *filename, uid_t uid)
 }
 
 /*
+ * Expand a string with a set of %[char] escapes. A number of escapes may be
+ * specified as (char *escape_chars, char *replacement) pairs. The list must
+ * be terminated by an escape_char of -1. Returns replaced string in memory
+ * allocated by xmalloc.
+ */
+char *
+percent_expand(const char *string, ...)
+{
+#define EXPAND_MAX_KEYS 16
+        struct {
+                const char *key;
+                const char *repl;
+        } keys[EXPAND_MAX_KEYS];
+        int num_keys, i, j;
+        char buf[4096];
+        va_list ap;
+
+        /* Gather keys */
+        va_start(ap, string);
+        for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
+                keys[num_keys].key = va_arg(ap, char *);
+                if (keys[num_keys].key == NULL)
+                        break;
+                keys[num_keys].repl = va_arg(ap, char *);
+                if (keys[num_keys].repl == NULL)
+                        fatal("percent_expand: NULL replacement");
+        }
+        va_end(ap);
+
+        if (num_keys >= EXPAND_MAX_KEYS)
+                fatal("percent_expand: too many keys");
+
+        /* Expand string */
+        *buf = '\0';
+        for (i = 0; *string != '\0'; string++) {
+                if (*string != '%') {
+ append:
+                        buf[i++] = *string;
+                        if (i >= sizeof(buf))
+                                fatal("percent_expand: string too long");
+                        buf[i] = '\0';
+                        continue;
+                }
+                string++;
+                if (*string == '%')
+                        goto append;
+                for (j = 0; j < num_keys; j++) {
+                        if (strchr(keys[j].key, *string) != NULL) {
+                                i = strlcat(buf, keys[j].repl, sizeof(buf));
+                                if (i >= sizeof(buf))
+                                        fatal("percent_expand: string too long");
+                                break;
+                        }
+                }
+                if (j >= num_keys)
+                        fatal("percent_expand: unknown key %%%c", *string);
+        }
+        return (xstrdup(buf));
+#undef EXPAND_MAX_KEYS
+}
+
+/*
  * Read an entire line from a public key file into a static buffer, discarding
  * lines that exceed the buffer size.  Returns 0 on success, -1 on failure.
  */
diff --git a/misc.h b/misc.h
index 798d80fbf..a85fcd134 100644
--- a/misc.h
+++ b/misc.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: misc.h,v 1.22 2005/04/09 04:32:54 djm Exp $   */
+/*      $OpenBSD: misc.h,v 1.23 2005/06/06 11:20:36 djm Exp $   */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -25,6 +25,7 @@ char	*cleanhostname(char *);
 char    *colon(char *);
 long     convtime(const char *);
 char    *tilde_expand_filename(const char *, uid_t);
+char    *percent_expand(const char *, ...) __attribute__((sentinel));
 
 struct passwd *pwcopy(struct passwd *);
 
diff --git a/ssh.c b/ssh.c
index 43ecbd924..0871d06de 100644
--- a/ssh.c
+++ b/ssh.c
@@ -40,7 +40,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh.c,v 1.240 2005/05/27 08:30:37 djm Exp $");
+RCSID("$OpenBSD: ssh.c,v 1.241 2005/06/06 11:20:36 djm Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -609,8 +609,12 @@ again:
                 options.proxy_command = NULL;
 
         if (options.control_path != NULL) {
-                options.control_path = tilde_expand_filename(
-                   options.control_path, original_real_uid);
+                snprintf(buf, sizeof(buf), "%d", options.port);
+                cp = tilde_expand_filename(options.control_path,
+                    original_real_uid);
+                options.control_path = percent_expand(cp, "p", buf, "h", host,
+                    "r", options.user, (char *)NULL);
+                xfree(cp);
         }
         if (mux_command != 0 && options.control_path == NULL)
                 fatal("No ControlPath specified for \"-O\" command");
diff --git a/ssh_config.5 b/ssh_config.5
index 18899ae58..2afc3c093 100644
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -34,7 +34,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: ssh_config.5,v 1.54 2005/05/23 23:32:46 djm Exp $
+.\" $OpenBSD: ssh_config.5,v 1.55 2005/06/06 11:20:36 djm Exp $
 .Dd September 25, 1999
 .Dt SSH_CONFIG 5
 .Os
@@ -279,10 +279,17 @@ can not be opened,
 .Nm ssh
 will continue without connecting to a master instance.
 .It Cm ControlPath
-Specify the path to the control socket used for connection sharing.
-See
+Specify the path to the control socket used for connection sharing as described
+in the
 .Cm ControlMaster
-above.
+section above.
+In the path,
+.Ql %h
+will be substituted by the target host name,
+.Ql %p
+the port and
+.Ql %r
+by the remote login username.
 .It Cm DynamicForward
 Specifies that a TCP/IP port on the local machine be forwarded
 over the secure channel, and the application
diff --git a/sshconnect.c b/sshconnect.c
index b79cead5d..0bd351f6b 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -13,7 +13,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect.c,v 1.163 2005/05/24 17:32:44 avsm Exp $");
+RCSID("$OpenBSD: sshconnect.c,v 1.164 2005/06/06 11:20:36 djm Exp $");
 
 #include <openssl/bn.h>
 
@@ -59,12 +59,11 @@ static void warn_changed_key(Key *);
 static int
 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
 {
-        Buffer command;
-        const char *cp;
-        char *command_string;
+        char *command_string, *tmp;
         int pin[2], pout[2];
         pid_t pid;
         char strport[NI_MAXSERV];
+        size_t len;
 
         /* Convert the port number into a string. */
         snprintf(strport, sizeof strport, "%hu", port);
@@ -76,31 +75,13 @@ ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
          * Use "exec" to avoid "sh -c" processes on some platforms
          * (e.g. Solaris)
          */
-        buffer_init(&command);
-        buffer_append(&command, "exec ", 5);
-
-        for (cp = proxy_command; *cp; cp++) {
-                if (cp[0] == '%' && cp[1] == '%') {
-                        buffer_append(&command, "%", 1);
-                        cp++;
-                        continue;
-                }
-                if (cp[0] == '%' && cp[1] == 'h') {
-                        buffer_append(&command, host, strlen(host));
-                        cp++;
-                        continue;
-                }
-                if (cp[0] == '%' && cp[1] == 'p') {
-                        buffer_append(&command, strport, strlen(strport));
-                        cp++;
-                        continue;
-                }
-                buffer_append(&command, cp, 1);
-        }
-        buffer_append(&command, "\0", 1);
-
-        /* Get the final command string. */
-        command_string = buffer_ptr(&command);
+        len = strlen(proxy_command) + 6;
+        tmp = xmalloc(len);
+        strlcpy(tmp, "exec ", len);
+        strlcat(tmp, proxy_command, len);
+        command_string = percent_expand(tmp, "h", host,
+            "p", strport, (char *)NULL);
+        xfree(tmp);
 
         /* Create pipes for communicating with the proxy. */
         if (pipe(pin) < 0 || pipe(pout) < 0)
@@ -154,7 +135,7 @@ ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
         close(pout[1]);
 
         /* Free the command name. */
-        buffer_free(&command);
+        xfree(command_string);
 
         /* Set the connection file descriptors. */
         packet_set_connection(pout[0], pin[1]);