CWE-462: Duplicate Key in Associative List (Alist)
Duplicate Key in Associative List (Alist)
Weakness ID: 462 (Weakness Base)
Status: Incomplete
Description
Description Summary
Duplicate keys in associative lists can lead to non-unique keys
being mistaken for an error.
Extended Description
A duplicate key entry -- if the alist is designed properly -- could be
used as a constant time replace function. However, duplicate key entries
could be inserted by mistake. Because of this ambiguity, duplicate key
entries in an association list are not recommended and should not be
allowed.
Time of Introduction
Architecture and Design
Implementation
Applicable Platforms
Languages
C
C++
Java
.NET
Likelihood of Exploit
Low
Demonstrative Examples
Example 1
The following code adds data to a list and then attempts to sort the
data.
(Bad Code)
alist = []
while (foo()): #now assume there is a string data with a key
basename
queue.append(basename,data)
queue.sort()
Since basename is not necessarily unique, this may not sort how one
would like it to be.
Potential Mitigations
Phase
Description
Architecture and Design
Use a hash table instead of an alist.
Architecture and Design
Use an alist which checks the uniqueness of hash keys with each entry
before inserting the entry.
Description
