The 4gig boundary will probably be important too with unsigned int in LP64, but since size_t will be 64-bit, there will have to be some truncation that compilers will be able to warn on. All content is copyright protected. uninitialized reference-type class members. , . MSBuild SonarQube Runner Resharper Plugin receives skipping info errors File not in sonarqube, SonarQube jenkins plugin returns "Server returned HTTP response code: -1, message: 'null' for URL: https://api.github.com/user", SonarQube: Ignore issues in blocks not working with regex, sonarLint complains "Null pointers should not be dereferenced (squid:S2259)" despite that possibility being handled, Java: (false?) [4] Is it possible to create a concave light? Not the answer you're looking for? The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. Since you cannot have a variable of type void, the pointer will not point to any data and therefore cannot be dereferenced. C static code analysis: Null pointers should not be dereferenced C static code analysis Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C code All rules 311 Vulnerability 13 Bug 74 Security Hotspot 18 Code Smell 206 Quick Fix 14 Tags "memset" should not be used to delete sensitive data Vulnerability Aaron:I suspect we are talking past each other. Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. That noncompliant code example (it's currently the 3rd) came from the Linux kernel, whose source is publicly available. And fwstr > is dereferenced in the following codes. We have a false positive with the " Null pointers should not be dereferenced -squid:S2259" rule : We have a "NullPointerException" false positive for which we do not know how to solve it. 1 Answer Sorted by: 2 Your code needs to do something about the possible NullPointerException when some exception is caught, because in this scenario the responseDto will be null. parsing /proc/self/maps under linux) one might find out whether the pointer points into mapped memory, but this is still not a guarantee of validity because it is very coarse-grained see again the above example. The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. Likewise, pointers to freed memory are not valid. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. String *x, y; X is a pointer to a string, Y is a string & = address of variable/ operator || referencing operator * = value of address || dereferencing operator Pointers = stores memory address as its variables NULL pointer = a constant with a value of zero defined || assigned to null Void pointer = a pointer that is not associated with any data types New operator = denotes a request for . (C11, S7.24.2.1). CWE-476: NULL Pointer Dereference: A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Small typo nit: "such as if i t pointed to freed memory" meant to say "if it" instead (removing whitespace). In multithreaded programs, null pointer dereferences can violate cache coherency policies and can cause resource leaks. We can get a reference to point to null in the following ways: "uninitialized" reference type variables variables which are initialized with nulls and are assigned their real value afterward. Rule squid:S2259 is based on a Symbolic Execution (SE) engine. SonarLint: A "NullPointerException" could be thrown; "getBody()" can return null. rev2023.3.3.43278. How to use Slater Type Orbitals as a basis functions in matrix method correctly? When you have a variable of non-primitive type, it is a reference to an object. static-code-analysis Reports. By 'valid pointers' I mean that both src and dest pointers are not null and they both point to non-overlapping arrays containing at least n bytes each. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. very old code or C code being worked into c++ may have functions that expect the user to delete the data. What is generic pointer? To learn more, see our tips on writing great answers. A NULL pointer can be dereferenced when signatures are being verified on PKCS7 signed or signedAndEnveloped data. What does it mean that a reference must refer to an object, not a dereferenced null pointer? res.getBody() == null || res.getBody().getServiceResult() == null). So let me be more precise in my wording: I assert that a platform whose memcpy() did anything besides copy zero bytes when given n=0 and valid src and dest pointers was not C-standards-compliant. So we have to check all the arguments before performing any actions. () Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? A reference to null should never be dereferenced/accessed. I am a student implementing stack with singly linked list using C, following a book called Fundamentals of Data Structures in C.. Thanks for contributing an answer to Stack Overflow! Issues Components. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? the Java one). Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, S2259: Null pointers should not be dereferenced, find the list of whitelisted methods here, Rule java:S2259: False-positive NullPointerException bug logged when variable is null-checked by an imported method, What is the issue you are observing, in details, What version of SonarSource products you are using, as well as the version of SonarJava. Is it possible to rotate a window 90 degrees if it has the same length and width? Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. Doing so will cause a NullPointerException to be thrown. How can we let this pass? The method takes a relation name r as input, executes the query "select * from r," and prints the result out in tabular format with the attribute names displayed in the table's header; the attribute names are displayed in the table's header. There are many ways to resolve this. As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. context.RaiseException . ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . After that, you call res.getBody() again. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. 1 Null pointers should not be dereferenced @CheckForNull String getName(){.} It is still a pointer though, to use it you just have to cast it to another kind of pointer first. Software project. {"serverDuration": 214, "requestCorrelationId": "084acdc104f21c51"}, EXP34-C. Do not dereference null pointers, Clever Attack Exploits Fully-Patched Linux Kernel, ERR33-C. Detect and handle standard library errors, one compliant and one non-compliant example, CERT Oracle Secure Coding Standard for Java, EXP01-J. Null pointer should not be dereferenced . Passing ownership of something also requires pointers. EXP34-C is a common consequence of ignoring function return values, but it is a distinct error, and can occur in other scenarios too. All content is copyright protected. name result . Best to cite C11 s7.24.2.1 here: The memcpy function copies n characters from the object pointed to by s2 into the object pointed to by s1. All rights are expressly reserved. Pointer members in structs are not checked. Since SIZE_MAX represents the largest possible object, the largest possible string would then be SIZE_MAX-1 characters long (excluding '\0'). Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? How can we prove that the supernatural or paranormal doesn't exist? 412-268-5800, If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer, or a pointer. The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. Interactions/interfaces with C can't use references. Hello. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. We really appreciate your help. Some Interesting Facts: 1) void pointers cannot be dereferenced. ncdu: What's going on with this second size column? In this noncompliant code example, input_str is copied into dynamically allocated memory referenced by c_str. In C, dereferencing a null pointer is undefined behavior. How do you ensure that a red herring doesn't violate Chekhov's gun? Find centralized, trusted content and collaborate around the technologies you use most. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. And if there is no pointer_default declaration, then the default default is ref. Using platform-specific means (e.g. Can you please start a new thread and be more explicit about the issue you are observing. If that variable hasn't had a reference assigned, it's a null reference, which (for internal/historical reasons) is referred to as a null pointer. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to bypass security measures. Are there tables of wastage rates for different fruit and veg? A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. I've changed it to say null pointer instead of invalid pointer. How do you ensure that a red herring doesn't violate Chekhov's gun? (in the meantime, in case of any other false-positive suspicion, make sure to check those latest versions as bunch of improvements are regularly released). 0 is certainly within the 'domain of the function' (a phrase defined by mathematics but not by C11), as copying 0 bytes is well-understood (although silly). That is, sets equivalent to a proper subset via an all-structure-preserving bijection. ability to run any cleanup processes. In my experience, there are reasons to check for a NULL pointer other than dereferencing it. isEmpty(Collection collection) Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. Trying to understand how to get this basic Fourier Series. Java Specification Participation Agreement version in use: 2.0. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. can have the value zero on a call to that function. Made code more compliant with other rules. (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) To learn more, see our tips on writing great answers. If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? A bug can cause them never to be reassigned. When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). It's even called out explicitly in C17 7.24.1p2: Where an argument declared as size_t n specifies the length of the array for a function, n can have the value zero on a call to that function. Mutually exclusive execution using std::atomic? NullPointerException is thrown when program attempts to use an object reference that has the null value. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Sonar: Null pointers should not be dereferenced, Why should Java 8's Optional not be used in arguments, Sonar alert : "private" methods that don't access instance data should be "static", sonarLint complains "Null pointers should not be dereferenced (squid:S2259)" despite that possibility being handled, Java: (false?) This issues is displayed by SonarQube. ), NPD.CHECK.CALL.MIGHTNPD.CHECK.CALL.MUSTNPD.CHECK.MIGHTNPD.CHECK.MUSTNPD.CONST.CALLNPD.CONST.DEREFNPD.FUNC.CALL.MIGHTNPD.FUNC.CALL.MUSTNPD.FUNC.MIGHTNPD.FUNC.MUSTNPD.GEN.CALL.MIGHTNPD.GEN.CALL.MUSTNPD.GEN.MIGHTNPD.GEN.MUSTRNPD.CALLRNPD.DEREF, 45 D, 123 D, 128 D, 129 D, 130 D, 131 D, 652 S, Checks for use of null pointers (rule partially covered). The indicated severity is for this more severe case; on platforms where it is not possible to exploit a null pointer dereference to execute arbitrary code, the actual severity is low. Basically, yes. The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. Dereferencing a null pointer is undefined behavior, typically abnormal program termination. This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. Additionally, if input_str is a null pointer, the call to strlen() dereferences a null pointer, also resulting in undefined behavior. And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). The test was added to catch the possibly theoretical situation where the length of input_str was somehow the maximum size for size_t, and adding one to this size in the malloc expression (to allocated space for the trailing null byte) results in an integer overflow. In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. points to memory allocated to the process) and what exactly was allocated there after the public key was freed, this may cause a segmentation fault or even execute code, which could again cause a segmentation fault, but might potentially be under the attacker's control. On such a call, a function that locates a character finds no occurrence, a function that compares two character sequences returns zero, and a function that copies characters copies zero characters. . At best, such an exception will cause abrupt program termination. ucsi->connector gets dereferenced by both ucsi_connector_change() and ucsi_resume(), both check for ucsi->connector being NULL in case ucsi_init() has not finished yet; or in case ucsi_init() has failed. As a result, this noncompliant code example is vulnerable to a null pointer dereference exploit, because null pointer dereferencing can be permitted on several platforms, for example, by using mmap(2) with the MAP_FIXED flag on Linux and Mac OS X, or by using the shmat() POSIX function with the SHM_RND flag [Liu 2009]. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. It also adds assertions to document that certain other pointers must not be null. At best, such an exception will cause abrupt program termination. On the command prompt, the same arguments work and the record is added in db but not when I call the stored procedure from inside java program CallableStatement insertStat = db_conn.prepareCall (" {call InsertCourses (?,?,?,?,?,?,?,? Its purpose is to serve as a special value for a pointer that could indicate a special condition in your program. NULL vs Void Pointer - Null pointer is a value, while void pointer is a type. Thanks, David! sonarLint (3.2.) Im currently using SonarQube version 5.6.6. better way to handle this is to store the result of method invocation in a variable. https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx )}"); Then we hit memcpy with length 0. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. There are many ways to resolve this. This sounds indeed like a bug in the flow when an exception is raised. Note that it doesn't know how to check for non-heap, non-stack. A null pointer stores a defined value, but one that is defined by the environment to not be a valid address for any member or object. In the meantime, Im locking this thread. I doubt that "length" of zero is a valid parameter, and although there no copy, but we see memory allocation. Seems the analizer don't recognice the logic with the funcional object Optional. Automated Detection Null pointer dereferences can happen in path-dependent ways. java In particular, ROSE ensures that any pointer returned by malloc(), calloc(), or realloc() is first checked for NULL before being used (otherwise, it is free()-ed). This code also violates ERR33-C. Detect and handle standard library errors. Why is there a voltage on my HDMI and coaxial cables? io.NotSerializableException : java. specifies the length of the array for a function. I added a comment to explain that SIZE_MAX is the limit of size_t. Instead use String.valueOf (object). At this point we define size as strlen(input_str) + 1. Dereferencing a null pointer can lead to a denial of service. The expected result here is solve the issue with sonarqube. Thanks for your relpy. Is there a proper earth ground point in this switch box? In the simplest case, this function just returns the result of calling kmalloc. 1 Answer Sorted by: 1 Your code is ok. Is there a proper earth ground point in this switch box? In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. This noncompliant code example is derived from a real-world example taken from a vulnerable version of the libpng library as deployed on a popular ARM-based cell phone [Jack 2007]. You're in a company-managed project. Passing a null pointer tomemcpy() would produce undefined behavior, even if the number of bytes to copy were 0. sonarqube Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 3.Null pointers should not be derefer enced/accessed. We resolved it by adding our tools path in the white list, and repackaging it. context.RaiseException , (/) The libpng library implements its own wrapper to malloc() that returns a null pointer on error or on being passed a 0-byte-length argument. Check whether a String is not Null and not Empty. Things go fine now. Could I capture, and I would be able to glean much security information from the dump? The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. This compliant solution ensures that the pointer returned by png_malloc() is not null. PS: I also tried the code in android studio which uses Lint and got no warnings. This is indeed an obvious False Positive from the rule. Cause we need throw our own Runtime Exception, well-known methods wont help. Alternate Terms Relationships . What does "Could not find or load main class" mean? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. int changed to size_t and if size_t parameter's is zero, allocate one word. Description The program can potentially dereference a null pointer, thereby raising a NullPointerException. IMHO, the rule title should be changed to something less general. So the first execution of ValidateNumber inside the foreach works fine and valid is set to true.The second execution throws the exception and exception is set in the catch-Block.. - the incident has nothing to do with me; can I use this this way? Trying to understand how to get this basic Fourier Series. The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. This compliant solution eliminates the null pointer deference by initializing sk to tun->sk following the null pointer check. Finally, there is the matter of the compliant solution. Recovering from a blunder I made while emailing a professor. Phew, we're agreed here. Ticket opened : Thanks a lot for the minimalized reproducer ! New replies are no longer allowed. It's still illegal. I believe in this case, either expression would work. Status: Dormant. Fixed by #1156 Contributor 94cb5f8 boris-unckel on Jul 28, 2021 9e62550 boris-unckel mentioned this issue on Jul 28, 2021 Closes #1155 - Null pointers should not be dereferenced #1156 Merged raiseException() return, Sonar Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. versions used (SonarQube, Scanner, language analyzer) Many platforms can support testing for those also. Trying to understand how to get this basic Fourier Series. To create a custom null validation method declare an attribute with name ValidatedNotNullAttribute and mark the parameter that is The solution that I recommend is not work with null returns or variables on Java, try to avoid it. ROSE does not handle cases where an allocation is assigned to an lvalue that is not a variable (such as a struct member or C++ function call returning a reference), Finds instances where a pointer is checked against NULL and then later dereferenced, Identifies functions that can return a null pointer but are not checked, Identifies code that dereferences a pointer and then checks the pointer against NULL, Can find the instances where NULL is explicitly dereferenced or a pointer is checked againstNULL but then dereferenced anyway. Making statements based on opinion; back them up with references or personal experience. , NPE : null-, . Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Reports. Search for vulnerabilities resulting from the violation of this rule on the CERT website. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. ), Does not guess that return values from malloc(), strchr(), etc., can be NULL (The return value from malloc() is NULL only if there is OOMo and the dev might not care to handle that. It is generally accepted that zeroing a pointer is a good way to mark it as invalid and dereferencing an invalid pointer is a bug. Unless explicitly stated otherwise in the description of a particular function in this subclause, pointer arguments on such a call shall still have valid values, as described in 7.1.4. If you write [ref], then a null pointer is not allowed, but if you write [unique], then a null pointer is permitted. Please direct comments on this JSR to the Spec Lead (s) Team. which version of SonarQube are you using? Does a summoned creature play immediately after being summoned by a ready action? We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. // <------- reported violation: NullPointerException might be thrown as 'bar' is nullable here, https://jira.sonarsource.com/browse/SONARJAVA-1490, https://groups.google.com/d/msgid/sonarqube/4752a999-246e-42c2-bbdc-8a44a5564ce9%40googlegroups.com. The correct idiom is to only allocate storage if the pointer is currently NULL. Haiku is a free and open-source operating system for PC designed to be binary compatible with the BeOS operating system and embodying the basic ideas of BeOS. Do not use a null in a case where an object is required, https://gcc.gnu.org/gcc-4.9/porting_to.html, Prior to 2018-01-12: CERT: Unspecified Relationship, Pointer Casting and Pointer Type Changes [HFC], Dereferencing an out-of-domain pointer [nullref], Section 5.2.18, "Null-Pointer Dereference", Dereferencing null pointers that were not returned by a function. Thank you for clarifying your assertion until I understood it properly. Provide a self-contained reproducer (zipped project?) ", Eclipse - Sonar S2629 possible false positive with new String, SonarQube null pointers should not be dereferenced on try/catch, getTextContent() through "Null pointers should not be dereferenced". In layman's terms, a null pointer is a pointer to an address in the memory space that does not have a meaningful value and cannot be referenced by the calling program, for whatever reason. util.regex.Matcher, java - Swing .getParent() . You can use Optional instead. Please explain: Without this, we wont be able to help you. In case the hash algorithm used for the signature is known to the OpenSSL library but the implementation of the hash algorithm is not available the digest initialization will fail. }. You need to benchmark. When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. That's true. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? My question is; is my solution incorrect? . But even with this, the concerned object it tagged as a possible NullPointerException problem. What is null pointer exception in android. This latter use of pointers is a combined boolean/satellite: the pointer being non-null indicates "I have this sister object", and it provides that object. Replacing broken pins/legs on a DIP IC package, Bulk update symbol size units from mm to map units in rule-based symbology, How do you get out of a corner when plotting yourself into a corner. In C# and Java, all reference types can point to null. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. Pittsburgh, PA 15213-2612
Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. Optimizers are optimizing based on this latitude and have been for years. See C17 7.1.4p1, which says, in part: Each of the following statements applies unless explicitly stated otherwise in the detailed descriptions that follow: If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer, or a pointerto non-modifiable storage when the corresponding parameter is not const-qualified) or a type (after default argument promotion) not expected by a function with a variable number of arguments, the behavior is undefined. , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow Just because something is a pointer does not mean you should call delete . And the semantics, as I said, are different. Find centralized, trusted content and collaborate around the technologies you use most. If you say [in] or [out] without a modifier, then the modifier defaults to the pointer_default for the enclosing class. in above code, Is there a single-word adjective for "having exceptionally strong moral principles"? Carnegie Mellon University
Coverity Prevent cannot discover all violations of this rule, so further verification is necessary, Detects when NULL is dereferenced (Array of pointers is not checked. . Can I tell police to wait and call a lawyer when served with a search warrant? The solution that I recommend is not work with null returns or variables on Java, try to avoid it. (from res.getBody().getServiceResult() ). But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. Styling contours by colour and by line thickness in QGIS. When and how should I use a ThreadLocal variable? What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? The method isNR (minRating) is a helper method that validate among other things, if the object minRating is null public boolean isNR (AgencyRating rating) { return rating == null || isNR (rating.getRatgCaam ()); } When I added the not null validation as sonar suggest.