more lenient RFC2047 decoding: accept illegal spaces and bare question marks in encod...

diff --git a/rfc2047.c b/rfc2047.c
index 8d4962531ae1e5e04c83a9dbfd0323b85b7870b2..7a117118ca3e0a003e0cbe26f2a4a0eac28e2685 100644 (file)
--- a/rfc2047.c
+++ b/rfc2047.c
@@ -629,12 +629,23 @@ static int rfc2047_decode_word (char *d, const char *s, size_t len)
   const char *t, *t1;
   int enc = 0, count = 0;
   char *charset = NULL;
+  int rv = -1;
 
   pd = d0 = safe_malloc (strlen (s));
 
   for (pp = s; (pp1 = strchr (pp, '?')); pp = pp1 + 1)
   {
     count++;
+
+    /* hack for non-compliant MUAs that allow unquoted question marks in encoded-text */
+    if (count == 4)
+    {
+      while (pp1 && *(pp1 + 1) != '=')
+       pp1 = strchr(pp1 + 1, '?');
+      if (!pp1)
+         goto error_out_0;
+    }
+
     switch (count)
     {
       case 2:
@@ -650,11 +661,7 @@ static int rfc2047_decode_word (char *d, const char *s, size_t len)
        else if (toupper ((unsigned char) *pp) == 'B')
          enc = ENCBASE64;
        else
-       {
-         FREE (&charset);
-         FREE (&d0);
-         return (-1);
-       }
+         goto error_out_0;
        break;
       case 4:
        if (enc == ENCQUOTEDPRINTABLE)
@@ -707,9 +714,11 @@ static int rfc2047_decode_word (char *d, const char *s, size_t len)
     mutt_convert_string (&d0, charset, Charset, M_ICONV_HOOK_FROM);
   mutt_filter_unprintable (&d0);
   strfcpy (d, d0, len);
+  rv = 0;
+error_out_0:
   FREE (&charset);
   FREE (&d0);
-  return (0);
+  return rv;
 }
 
 /*
@@ -731,7 +740,8 @@ static const char *find_encoded_word (const char *s, const char **x)
       ;
     if (q[0] != '?' || !strchr ("BbQq", q[1]) || q[2] != '?')
       continue;
-    for (q = q + 3; 0x20 < *q && *q < 0x7f && *q != '?'; q++)
+    /* non-strict check since many MUAs will not encode spaces and question marks */
+    for (q = q + 3; 0x20 <= *q && *q < 0x7f && (*q != '?' || q[1] != '='); q++)
       ;
     if (q[0] != '?' || q[1] != '=')
     {