Don't output snoop information when doing RETR or TOP.

[nmh] / sbr / netsec.c

diff --git a/sbr/netsec.c b/sbr/netsec.c
index f6217c1d17a58b8cc482f53451a9e2af01008097..18bb97ac311cb92ab9fe99f7b9ff41e9bb7b3edf 100644 (file)
--- a/sbr/netsec.c
+++ b/sbr/netsec.c
@@ -99,6 +99,12 @@ struct _netsec_context {
 
 static int netsec_fillread(netsec_context *ns_context, char **errstr);
 
+/*
+ * Code to check the ASCII content of a byte array.
+ */
+
+static int checkascii(const unsigned char *byte, size_t len);
+
 /*
  * How this code works, in general.
  *
@@ -286,7 +292,7 @@ void
 netsec_b64_snoop_decoder(netsec_context *nsc, const char *string, size_t len,
                         void *context)
 {
-    const char *decoded;
+    unsigned char *decoded;
     size_t decodedlen;
     int offset;
     NMH_UNUSED(nsc);
@@ -303,16 +309,48 @@ netsec_b64_snoop_decoder(netsec_context *nsc, const char *string, size_t len,
     }
 
     if (decodeBase64(string, &decoded, &decodedlen, 1, NULL) == OK) {
-       char *hexified;
-       hexify((const unsigned char *) decoded, decodedlen, &hexified);
-       fprintf(stderr, "b64<%s>\n", hexified);
-       free(hexified);
-       free((char *) decoded);
+       /*
+        * Some mechanisms preoduce large binary tokens, which aren't really
+        * readable.  So let's do a simple heuristic.  If the token is greater
+        * than 100 characters _and_ the first 100 bytes are more than 50%
+        * non-ASCII, then don't print the decoded buffer, just the
+        * base64 text.
+        */
+       if (decodedlen > 100 && !checkascii(decoded, 100)) {
+           fprintf(stderr, "%.*s\n", (int) len, string);
+       } else {
+           char *hexified;
+           hexify(decoded, decodedlen, &hexified);
+           fprintf(stderr, "b64<%s>\n", hexified);
+           free(hexified);
+       }
+       free(decoded);
     } else {
        fprintf(stderr, "%.*s\n", (int) len, string);
     }
 }
 
+/*
+ * If the ASCII content is > 50%, return 1
+ */
+
+static int
+checkascii(const unsigned char *bytes, size_t len)
+{
+    size_t count = 0, half = len / 2;
+
+    while (len-- > 0) {
+       if (isascii(*bytes) && isprint(*bytes) && ++count > half)
+           return 1;
+       bytes++;
+       /* No chance by this point */
+       if (count + len < half)
+           return 0;
+    }
+
+    return 0;
+}
+
 /*
  * Set the read timeout for this connection
  */