Source:

Internal

Info:

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3469

The (1) asn1_read_value_type and (2) asn1_read_value functions in GNU Libtasn1 

before 3.6 allows context-dependent attackers to cause a denial of service 

(NULL pointer dereference and crash) via a NULL value in an ivalue argument.

Status:

Need to determine if this patch has been sent upstream.

--- libtasn1-2.8/lib/element.c.orig	2014-06-05 10:41:52.955725412 +0530

+++ libtasn1-2.8/lib/element.c	2014-06-05 11:09:52.177695875 +0530

@@ -113,8 +113,11 @@ _asn1_convert_integer (const char *value

     /* VALUE_OUT is too short to contain the value conversion */

     return ASN1_MEM_ERROR;

-  for (k2 = k; k2 < SIZEOF_UNSIGNED_LONG_INT; k2++)

+  if (value_out != NULL)

+  {

+    for (k2 = k; k2 < SIZEOF_UNSIGNED_LONG_INT; k2++)

     value_out[k2 - k] = val[k2];

+  }

 #if 0

   printf ("_asn1_convert_integer: valueIn=%s, lenOut=%d", value, *len);

@@ -622,7 +625,8 @@ asn1_write_value (ASN1_TYPE node_root, c

 	if (ptr_size < data_size) { \

 		return ASN1_MEM_ERROR; \

 	} else { \

-		memcpy( ptr, data, data_size); \

+		if (ptr && data_size > 0) \

+			memcpy( ptr, data, data_size); \

 	}

 #define PUT_STR_VALUE( ptr, ptr_size, data) \

@@ -631,36 +635,39 @@ asn1_write_value (ASN1_TYPE node_root, c

 		return ASN1_MEM_ERROR; \

 	} else { \

 		/* this strcpy is checked */ \

-		strcpy(ptr, data); \

+		if (ptr) { \

+			strcpy(ptr, data); \

+		} \

 	}

 #define ADD_STR_VALUE( ptr, ptr_size, data) \

-	*len = (int) strlen(data) + 1; \

-	if (ptr_size < (int) strlen(ptr)+(*len)) { \

+	*len += strlen(data); \

+	if (ptr_size < (int) *len) { \

+		(*len)++; \

 		return ASN1_MEM_ERROR; \

 	} else { \

 		/* this strcat is checked */ \

-		strcat(ptr, data); \

+		if (ptr) strcat (ptr, data); \

 	}

-

 /**

  * asn1_read_value:

  * @root: pointer to a structure.

  * @name: the name of the element inside a structure that you want to read.

  * @ivalue: vector that will contain the element's content, must be a

- *   pointer to memory cells already allocated.

+ *   pointer to memory cells already allocated (may be %NULL).

  * @len: number of bytes of *value: value[0]..value[len-1]. Initialy

  *   holds the sizeof value.

  *

  * Returns the value of one element inside a structure.

- *

- * If an element is OPTIONAL and the function "read_value" returns

+ * If an element is OPTIONAL and this returns

  * %ASN1_ELEMENT_NOT_FOUND, it means that this element wasn't present

  * in the der encoding that created the structure.  The first element

  * of a SEQUENCE_OF or SET_OF is named "?1". The second one "?2" and

  * so on.

  *

- * INTEGER: VALUE will contain a two's complement form integer.

+ * Note that there can be valid values with length zero. In these case

+ * this function will succeed and @len will be zero.

+ *

  *

  *            integer=-1  -> value[0]=0xFF , len=1.

  *            integer=1   -> value[0]=0x01 , len=1.