Add randstr expansion to generate random strings up to 256 bytes

diff --git a/src/modules/rlm_expr/rlm_expr.c b/src/modules/rlm_expr/rlm_expr.c
index bcb9bb98783afc2a44fe8e1d3c2c311ccab7f31e..27ee04670de0fc7b6fa3cdfead3a5259afedea6c 100644 (file)
--- a/src/modules/rlm_expr/rlm_expr.c
+++ b/src/modules/rlm_expr/rlm_expr.c
@@ -65,6 +65,12 @@ static expr_map_t map[] =
        {0,     TOKEN_LAST}
 };
 
+/*
+ *     Lookup tables for randstr char classes
+ */
+static char randstr_punc[32] = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~";
+static char randstr_salt[] = ".0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmopqrstuvwxyz/";
+
 static int get_number(REQUEST *request, const char **string, int64_t *answer)
 {
        int             i, found;
@@ -288,6 +294,84 @@ static size_t rand_xlat(void *instance, REQUEST *request, char *fmt,
        return strlen(out);
 }
 
+/*
+ *  Build strings of random chars, useful for generating tokens and passcodes
+ *  Format identical to String::Random.
+ */
+static size_t randstr_xlat(void *instance, REQUEST *request, const char *fmt,
+                       char *out, size_t outlen,
+                       RADIUS_ESCAPE_STRING func)
+{
+       rlm_expr_t      *inst = instance;
+       char            buffer[256];
+       unsigned int    result;
+       size_t          s = outlen;
+       size_t          len;
+       char            *p;
+       
+       inst = inst;            /* -Wunused */
+
+       /*
+        * Do an xlat on the provided string (nice recursive operation).
+        */
+       len = radius_xlat(buffer, sizeof(buffer), fmt, request, func);
+       if (!len) {
+               radlog(L_ERR, "rlm_expr: xlat failed.");
+               return 0;
+       }
+       
+       p = buffer;
+       while ((len-- > 0) && (--s > 0)) {
+               result = fr_rand();
+               switch (*p) {
+                       case 'c':
+                               *out++ = 'a' + (result % 26);
+                       break;
+                       
+                       case 'C':
+                               *out++ = 'A' + (result % 26);
+                       break;
+                       
+                       case 'n':
+                               *out++ = '0' + (result % 10);
+                       break;
+                       
+                       case '!':
+                               *out++ = randstr_punc[result % (sizeof(randstr_punc) - 1)];
+                       break;
+                       
+                       case '.':
+                               *out++ = '!' + (result % 95);
+                       break;
+                       
+                       case 's':
+                               *out++ = randstr_salt[result % (sizeof(randstr_salt) - 1)];
+                       break;
+                       
+                       /*
+                        *  Don't output NULLs apparently some places in the 
+                        *  code still use them instead of the length returned.
+                        */
+                       case 'b':
+                               *out++ = (result % 255) + 1;
+                       break;
+                       
+                       default:
+                               radlog(L_ERR,
+                                      "rlm_expr: invalid character class '%c'", *p);
+                                      
+                               return 0;
+                       break;
+               }
+       
+               p++;
+       }
+       
+       *out++ = '\0';
+       
+       return outlen - s;
+}
+
 /*
  *     Do any per-module initialization that is separate to each
  *     configured instance of the module.  e.g. set up connections
@@ -321,6 +405,7 @@ static int expr_instantiate(CONF_SECTION *conf, void **instance)
        }
 
        xlat_register("rand", rand_xlat, inst);
+       xlat_register("randstr", randstr_xlat, inst);
 
        /*
         * Initialize various paircompare functions