1. openvpn
  2. Commit b1263b06db40f21a8fd20e0efd0c12e37ce89a2c
Browse code

Ensure strings read from registry are null-terminated

- Strings stored in registry are not guaranteed to be null-terminated.
So, use RegGetValue() instead of RegQueryValueEx() as the former
adds null termination to the returned string if missing.
(Needs Windows Vista+)

- While at it also add a default value parameter to GetRegString()
to process optional registry values (such as ovpn_admin_group)
without causing an otherwise confusing error logged to the
eventlog[*].

[*] see Trac: #892

Signed-off-by: Selva Nair <selva.nair@gmail.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1511026858-23281-1-git-send-email-selva.nair@gmail.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15893.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

Selva Nair authored on 2017/11/19 02:40:57
Showing 1 changed files
src/openvpnserv/common.c
History View file @ b1263b0
... ... 
@@ -57,14 +57,18 @@ openvpn_sntprintf(LPTSTR str, size_t size, LPCTSTR format, ...)
57 57 
 }
58 58
59 59 
 static DWORD
60 
-GetRegString(HKEY key, LPCTSTR value, LPTSTR data, DWORD size)
60 
+GetRegString(HKEY key, LPCTSTR value, LPTSTR data, DWORD size, LPCTSTR default_value)
61 61 
 {
62 
-    DWORD type;
63 
-    LONG status = RegQueryValueEx(key, value, NULL, &type, (LPBYTE) data, &size);
62 
+    LONG status = RegGetValue(key, NULL, value, RRF_RT_REG_SZ|RRF_RT_REG_EXPAND_SZ,
63 
+                              NULL, (LPBYTE) data, &size);
64 64
65 
-    if (status == ERROR_SUCCESS && type != REG_SZ)
65 
+    if (status == ERROR_FILE_NOT_FOUND && default_value)
66 66 
     {
67 
-        status = ERROR_DATATYPE_MISMATCH;
67 
+        size_t len = size/sizeof(data[0]);
68 
+        if (openvpn_sntprintf(data, len, default_value) > 0)
69 
+        {
70 
+            status = ERROR_SUCCESS;
71 
+        }
68 72 
     }
69 73
70 74 
     if (status != ERROR_SUCCESS)
... ... 
@@ -95,48 +99,48 @@ GetOpenvpnSettings(settings_t *s)
95 95 
         return MsgToEventLog(M_SYSERR, TEXT("Could not open Registry key HKLM\\%s not found"), reg_path);
96 96 
     }
97 97
98 
-    error = GetRegString(key, TEXT("exe_path"), s->exe_path, sizeof(s->exe_path));
98 
+    error = GetRegString(key, TEXT("exe_path"), s->exe_path, sizeof(s->exe_path), NULL);
99 99 
     if (error != ERROR_SUCCESS)
100 100 
     {
101 101 
         goto out;
102 102 
     }
103 103
104 
-    error = GetRegString(key, TEXT("config_dir"), s->config_dir, sizeof(s->config_dir));
104 
+    error = GetRegString(key, TEXT("config_dir"), s->config_dir, sizeof(s->config_dir), NULL);
105 105 
     if (error != ERROR_SUCCESS)
106 106 
     {
107 107 
         goto out;
108 108 
     }
109 109
110 
-    error = GetRegString(key, TEXT("config_ext"), s->ext_string, sizeof(s->ext_string));
110 
+    error = GetRegString(key, TEXT("config_ext"), s->ext_string, sizeof(s->ext_string), NULL);
111 111 
     if (error != ERROR_SUCCESS)
112 112 
     {
113 113 
         goto out;
114 114 
     }
115 115
116 
-    error = GetRegString(key, TEXT("log_dir"), s->log_dir, sizeof(s->log_dir));
116 
+    error = GetRegString(key, TEXT("log_dir"), s->log_dir, sizeof(s->log_dir), NULL);
117 117 
     if (error != ERROR_SUCCESS)
118 118 
     {
119 119 
         goto out;
120 120 
     }
121 121
122 
-    error = GetRegString(key, TEXT("priority"), priority, sizeof(priority));
122 
+    error = GetRegString(key, TEXT("priority"), priority, sizeof(priority), NULL);
123 123 
     if (error != ERROR_SUCCESS)
124 124 
     {
125 125 
         goto out;
126 126 
     }
127 127
128 
-    error = GetRegString(key, TEXT("log_append"), append, sizeof(append));
128 
+    error = GetRegString(key, TEXT("log_append"), append, sizeof(append), NULL);
129 129 
     if (error != ERROR_SUCCESS)
130 130 
     {
131 131 
         goto out;
132 132 
     }
133 133
134 134 
     /* read if present, else use default */
135 
-    error = GetRegString(key, TEXT("ovpn_admin_group"), s->ovpn_admin_group, sizeof(s->ovpn_admin_group));
135 
+    error = GetRegString(key, TEXT("ovpn_admin_group"), s->ovpn_admin_group,
136 
+                         sizeof(s->ovpn_admin_group), OVPN_ADMIN_GROUP);
136 137 
     if (error != ERROR_SUCCESS)
137 138 
     {
138 
-        openvpn_sntprintf(s->ovpn_admin_group, _countof(s->ovpn_admin_group), OVPN_ADMIN_GROUP);
139 
-        error = 0; /* this error is not fatal */
139 
+        goto out;
140 140 
     }
141 141 
     /* set process priority */
142 142 
     if (!_tcsicmp(priority, TEXT("IDLE_PRIORITY_CLASS")))