...
| Code Block | ||
|---|---|---|
| ||
public static int cardinality(Object obj, final Collection col) {
int count = 0;
Iterator it = col.iterator();
while (it.hasNext()) {
Object elt = it.next();
if ((null == obj && null == elt) ||
(null != obj && obj.equals(elt))) {
count++;
}
}
return count;
}
|
Automated Detection
| Wiki Markup |
|---|
Null pointer dereferences can happen in path-dependent ways. Limitations of automatic detection tools can require manual inspection of code \[[Hovemeyer 2007|AA. Bibliography#Hovemeyer 07]\] to detect instances of null pointer dereferences. Annotations for method parameters that must be non-null can reduce the need for manual inspection by assisting automated null pointer dereference detection. |
Risk Assessment
| Wiki Markup |
|---|
Dereferencing a {{null}} pointer can lead to a denial of service. For example, Java Web Start applications and applets particular to JDK version 1.6, prior to update 4, were affected by a bug that had some noteworthy security consequences. A {{NullPointerException}} was generated in some isolated cases when the application or applet attempted to establish an HTTPS connection with a server \[[SDN 2008|AA. Bibliography#SDN 08]\]. The failure to establish a secure HTTPS connection with the server caused a denial of service: clients were temporarily forced to use an insecure http channel for data exchange. In multithreaded programs, null pointer dereferences can violate cache coherency policies and can cause resource leaks. |
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
EXP08-J | low | likely | high | P3 | L3 |
Automated Detection
| Wiki Markup |
|---|
Null pointer dereferences can happen in path-dependent ways. Limitations of automatic detection tools can require manual inspection of code \[[Hovemeyer 2007|AA. Bibliography#Hovemeyer 07]\] to detect instances of null pointer dereferences. Annotations for method parameters that must be non-null can reduce the need for manual inspection by assisting automated null pointer dereference detection. |
The Coverity Prevent Version 5.0 FORWARD_NULL checker can detect the instance where reference is checked against null but then dereferenced anyway.
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<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="e8e74e662349d9e2-0261139a-4d504bb4-8e0fa686-2eece2ee4ab499020be60583"><ac:plain-text-body><![CDATA[ | [[API 2006 | AA. Bibliography#API 06]] | [method doPrivileged() | http://java.sun.com/javase/6/docs/api/java/security/AccessController.html#doPrivileged(java.security.PrivilegedAction)] | ]]></ac:plain-text-body></ac:structured-macro> |
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="87df3eed80efd4c9-3a7396e4-4ba94ab0-bfaf885b-40aaebfc86c52c768a1d8687"><ac:plain-text-body><![CDATA[ | [[Hovemeyer 2007 | AA. Bibliography#Hovemeyer 07]] |
| ]]></ac:plain-text-body></ac:structured-macro> | |
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="47196ab206a4b701-df7da068-4b504a0c-80139a9e-304cc54149d0c8a4b3722cdf"><ac:plain-text-body><![CDATA[ | [[Reasoning 2003 | AA. Bibliography#Reasoning 03]] | Defect ID 00-0001 | ]]></ac:plain-text-body></ac:structured-macro> | |
| Null Pointer Dereference | ||||
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="c30d2c25fe253d78-c556d858-49aa4c2e-aa9ab28a-b1545beffc533464645b95e1"><ac:plain-text-body><![CDATA[ | [[SDN 2008 | AA. Bibliography#SDN 08]] | [Bug ID 6514454 | http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6514454] | ]]></ac:plain-text-body></ac:structured-macro> |
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