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Common Weakness Enumeration

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ID

CWE-663: Use of a Non-reentrant Function in a Concurrent Context

Weakness ID: 663
Vulnerability Mapping: ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities
Abstraction: BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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+ Description
The product calls a non-reentrant function in a concurrent context in which a competing code sequence (e.g. thread or signal handler) may have an opportunity to call the same function or otherwise influence its state.
+ Common Consequences
Section HelpThis table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
ScopeImpactLikelihood
Integrity
Confidentiality
Other

Technical Impact: Modify Memory; Read Memory; Modify Application Data; Read Application Data; Alter Execution Logic

+ Potential Mitigations

Phase: Implementation

Use reentrant functions if available.

Phase: Implementation

Add synchronization to your non-reentrant function.

Phase: Implementation

In Java, use the ReentrantLock Class.
+ Relationships
Section HelpThis table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.
+ Relevant to the view "Research Concepts" (CWE-1000)
NatureTypeIDName
ChildOfClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.662Improper Synchronization
ParentOfVariantVariant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.479Signal Handler Use of a Non-reentrant Function
ParentOfVariantVariant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.558Use of getlogin() in Multithreaded Application
PeerOfBaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.1265Unintended Reentrant Invocation of Non-reentrant Code Via Nested Calls
Section HelpThis table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.
+ Relevant to the view "Software Development" (CWE-699)
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.557Concurrency Issues
+ Modes Of Introduction
Section HelpThe different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.
PhaseNote
Implementation
+ Demonstrative Examples

Example 1

In this example, a signal handler uses syslog() to log a message:

(bad code)
 
char *message;
void sh(int dummy) {
syslog(LOG_NOTICE,"%s\n",message);
sleep(10);
exit(0);
}
int main(int argc,char* argv[]) {
...
signal(SIGHUP,sh);
signal(SIGTERM,sh);
sleep(10);
exit(0);
}
If the execution of the first call to the signal handler is suspended after invoking syslog(), and the signal handler is called a second time, the memory allocated by syslog() enters an undefined, and possibly, exploitable state.

Example 2

The following code relies on getlogin() to determine whether or not a user is trusted. It is easily subverted.

(bad code)
Example Language:
pwd = getpwnam(getlogin());
if (isTrustedGroup(pwd->pw_gid)) {
allow();
} else {
deny();
}

+ Observed Examples
ReferenceDescription
unsafe calls to library functions from signal handler
SIGCHLD signal to FTP server can cause crash under heavy load while executing non-reentrant functions like malloc/free.
+ Memberships
Section HelpThis MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.986SFP Secondary Cluster: Missing Lock
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1401Comprehensive Categorization: Concurrency
+ Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.
+ References
[REF-547] SUN. "Java Concurrency API". Class ReentrantLock. <https://docs.oracle.com/javase/1.5.0/docs/api/java/util/concurrent/locks/ReentrantLock.html>. URL validated: 2023-04-07.
[REF-548] Dipak Jha, Software Engineer, IBM. "Use reentrant functions for safer signal handling". <https://archive.ph/rl1XR>. URL validated: 2023-04-07.
+ Content History
+ Submissions
Submission DateSubmitterOrganization
2008-04-11
(CWE Draft 9, 2008-04-11)
CWE Community
Submitted by members of the CWE community to extend early CWE versions
+ Modifications
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated References, Potential_Mitigations, Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Relationships, References
2009-03-10CWE Content TeamMITRE
updated Related_Attack_Patterns
2010-09-27CWE Content TeamMITRE
updated Name, Observed_Examples, Potential_Mitigations, References, Relationships
2010-12-13CWE Content TeamMITRE
updated Description, Name, Relationships
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Relationships
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-11-08CWE Content TeamMITRE
updated Observed_Examples
2020-02-24CWE Content TeamMITRE
updated Relationships
2020-06-25CWE Content TeamMITRE
updated Relationships
2020-12-10CWE Content TeamMITRE
updated Common_Consequences
2023-01-31CWE Content TeamMITRE
updated Description
2023-04-27CWE Content TeamMITRE
updated References, Relationships, Time_of_Introduction
2023-06-29CWE Content TeamMITRE
updated Mapping_Notes
2023-10-26CWE Content TeamMITRE
updated Demonstrative_Examples
+ Previous Entry Names
Change DatePrevious Entry Name
2010-09-27Use of a Non-reentrant Function in an Unsynchronized Context
2010-12-13Use of a Non-reentrant Function in a Multithreaded Context
Page Last Updated: July 16, 2024