- djm@cvs.openbsd.org 2012/11/04 10:38:43

     [auth2-pubkey.c sshd.c sshd_config.5]
     Remove default of AuthorizedCommandUser. Administrators are now expected
     to explicitly specify a user. feedback and ok markus@

1 files changed, 17 insertions, 13 deletions

diff --git a/auth2-pubkey.c b/auth2-pubkey.c
index ec8f75d57..6a6217017 100644
--- a/auth2-pubkey.c
+++ b/auth2-pubkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-pubkey.c,v 1.31 2012/10/30 21:29:54 djm Exp $ */
+/* $OpenBSD: auth2-pubkey.c,v 1.32 2012/11/04 10:38:43 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -462,23 +462,27 @@ user_key_command_allowed2(struct passwd *user_pw, Key *key)
         struct stat st;
         int status, devnull, p[2], i;
         pid_t pid;
-        char errmsg[512];
+        char *username, errmsg[512];
 
         if (options.authorized_keys_command == NULL ||
             options.authorized_keys_command[0] != '/')
                 return 0;
 
-        /* If no user specified to run commands the default to target user */
-        if (options.authorized_keys_command_user == NULL)
-                pw = user_pw;
-        else {
-                pw = getpwnam(options.authorized_keys_command_user);
-                if (pw == NULL) {
-                        error("AuthorizedKeyCommandUser \"%s\" not found: %s",
-                            options.authorized_keys_command, strerror(errno));
-                        return 0;
-                }
+        if (options.authorized_keys_command_user == NULL) {
+                error("No user for AuthorizedKeysCommand specified, skipping");
+                return 0;
+        }
+
+        username = percent_expand(options.authorized_keys_command_user,
+            "u", user_pw->pw_name, (char *)NULL);
+        pw = getpwnam(username);
+        if (pw == NULL) {
+                error("AuthorizedKeyCommandUser \"%s\" not found: %s",
+                    options.authorized_keys_command, strerror(errno));
+                free(username);
+                return 0;
         }
+        free(username);
 
         temporarily_use_uid(pw);
 
@@ -517,6 +521,7 @@ user_key_command_allowed2(struct passwd *user_pw, Key *key)
                 for (i = 0; i < NSIG; i++)
                         signal(i, SIG_DFL);
 
+                closefrom(STDERR_FILENO + 1);
                 /* Don't use permanently_set_uid() here to avoid fatal() */
                 if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
                         error("setresgid %u: %s", (u_int)pw->pw_gid,
@@ -541,7 +546,6 @@ user_key_command_allowed2(struct passwd *user_pw, Key *key)
                         error("%s: dup2: %s", __func__, strerror(errno));
                         _exit(1);
                 }
-                closefrom(STDERR_FILENO + 1);
 
                 execl(options.authorized_keys_command,
                     options.authorized_keys_command, pw->pw_name, NULL);