Missing Release of Memory after Effective Lifetime

The software does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.


Description

This is often triggered by improper handling of malformed data or unexpectedly interrupted sessions. In some languages, developers are responsible for tracking memory allocation and releasing the memory. If there are no more pointers or references to the memory, then it can no longer be tracked and identified for release.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

The following C function leaks a block of allocated memory if the call to read() does not return the expected number of bytes:

char* getBlock(int fd) {

  char* buf = (char*) malloc(BLOCK_SIZE);
  if (!buf) {
    return NULL;
  }
  if (read(fd, buf, BLOCK_SIZE) != BLOCK_SIZE) {


    return NULL;

  }
  return buf;

}

See Also

SFP Primary Cluster: Failure to Release Memory

This category identifies Software Fault Patterns (SFPs) within the Failure to Release Memory cluster (SFP38).

SEI CERT C Coding Standard - Guidelines 08. Memory Management (MEM)

Weaknesses in this category are related to the rules and recommendations in the Memory Management (MEM) section of the SEI CERT C Coding Standard.

SEI CERT Oracle Secure Coding Standard for Java - Guidelines 49. Miscellaneous (MSC)

Weaknesses in this category are related to the rules and recommendations in the Miscellaneous (MSC) section of the SEI CERT Oracle Secure Coding Standard for Java.

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Weaknesses Introduced During Implementation

This view (slice) lists weaknesses that can be introduced during implementation.

Weaknesses Introduced During Design

This view (slice) lists weaknesses that can be introduced during design.


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