[SCM] GNU libtasn1 branch, master, updated. libtasn1_4_1-3-ge91cb99

[Nikos Mavrogiannopoulos]

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- Log -----------------------------------------------------------------
commit e91cb99ce0b2e01b0ea1ec9e57415f0e2064560c
Author: Nikos Mavrogiannopoulos <address@hidden>
Date:   Fri Aug 29 17:24:41 2014 +0200

    doc update

commit 39fe038987321079016f9ace2beac13758523d8c
Author: Nikos Mavrogiannopoulos <address@hidden>
Date:   Fri Aug 29 16:35:43 2014 +0200

    updated todo

commit 564ca04592ad5604fe5c7344ec9e62bc04879ef7
Author: Nikos Mavrogiannopoulos <address@hidden>
Date:   Fri Aug 29 16:34:39 2014 +0200

    perform sanity checks in Time field

-----------------------------------------------------------------------

Summary of changes:
 NEWS           |    3 +++
 doc/TODO       |    4 ++--
 lib/decoding.c |   55 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/NEWS b/NEWS
index 49a0929..c4ad461 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,8 @@
 GNU Libtasn1 NEWS                                     -*- outline -*-
 
+* Noteworthy changes in release 4.2 (unreleased) [stable]
+- Added sanity checks in the decoding of time
+
 * Noteworthy changes in release 4.1 (released 2014-08-23) [stable]
 - Corrected indefinite tag check in ANY constructions. That allows
   the decoding of BER-encoded structures that contain indefinite
diff --git a/doc/TODO b/doc/TODO
index cf2b029..58abcd2 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -4,8 +4,8 @@ in order to avoid having people working on the same thing.
 
 Current list:
 + Audit the code
-+ Eliminate the need for ltostr() and its reverse
-+ C structure generation instead of a single array
+* Allow extracting the time in a reasonable format (e.g. time_t)
+* C structure generation instead of a single array
 - Add the checking of default value (e.g. 'INTEGER DEFAULT v1')
 - Check _asn1_objectid_der, crashes on "0" input, gives incorrect encoding?
 
diff --git a/lib/decoding.c b/lib/decoding.c
index fd6ef5b..9622fda 100644
--- a/lib/decoding.c
+++ b/lib/decoding.c
@@ -276,12 +276,17 @@ asn1_get_octet_der (const unsigned char *der, int der_len,
 }
 
 /* Returns ASN1_SUCCESS on success or an error code on error.
+ * type should be one of ASN1_ETYPE_GENERALIZED_TIME or ASN1_ETYPE_UTC_TIME.
  */
 static int
-_asn1_get_time_der (const unsigned char *der, int der_len, int *ret_len,
-                   char *str, int str_size)
+_asn1_get_time_der (unsigned type, const unsigned char *der, int der_len, int 
*ret_len,
+                   char *str, int str_size, unsigned flags)
 {
   int len_len, str_len;
+  unsigned i;
+  unsigned sign_count = 0;
+  unsigned dot_count = 0;
+  const unsigned char *p;
 
   if (der_len <= 0 || str == NULL)
     return ASN1_DER_ERROR;
@@ -290,6 +295,48 @@ _asn1_get_time_der (const unsigned char *der, int der_len, 
int *ret_len,
   if (str_len <= 0 || str_size < str_len)
     return ASN1_DER_ERROR;
 
+  /* perform some sanity checks on the data */
+  if (str_len < 8)
+    {
+      warn();
+      return ASN1_DER_ERROR;
+    }
+
+  p = &der[len_len];
+  for (i=0;i<str_len-1;i++)
+     {
+       if (isdigit(p[i]) == 0)
+         {
+           if (type == ASN1_ETYPE_GENERALIZED_TIME)
+             {
+               /* tolerate lax encodings */
+               if (p[i] == '.' && dot_count == 0)
+                 {
+                   dot_count++;
+                   continue;
+                 }
+
+              /* This is not really valid DER, but there are
+               * structures using that */
+               if (!(flags & ASN1_DECODE_FLAG_STRICT_DER) &&
+                   (p[i] == '+' || p[i] == '-') && sign_count == 0)
+                 {
+                   sign_count++;
+                   continue;
+                 }
+             }
+
+           warn();
+          return ASN1_DER_ERROR;
+         }
+     }
+
+  if (sign_count == 0 && p[str_len-1] != 'Z')
+    {
+      warn();
+      return ASN1_DER_ERROR;
+    }
+
   memcpy (str, der + len_len, str_len);
   str[str_len] = 0;
   *ret_len = str_len + len_len;
@@ -1181,8 +1228,8 @@ asn1_der_decoding2 (asn1_node *element, const void *ider, 
int *max_ider_len,
            case ASN1_ETYPE_GENERALIZED_TIME:
            case ASN1_ETYPE_UTC_TIME:
              result =
-               _asn1_get_time_der (der + counter, ider_len, &len2, temp,
-                                   sizeof (temp) - 1);
+               _asn1_get_time_der (type_field (p->type), der + counter, 
ider_len, &len2, temp,
+                                   sizeof (temp) - 1, flags);
              if (result != ASN1_SUCCESS)
                {
                   warn();


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