All content is copyright protected. Your code needs to do something about the possible NullPointerException when some exception is caught, because in this scenario the responseDto will be null. Write a semantic patch to nd cases where the result of calling kmalloc is dereferenced with no previous NULL pointer test. Is there a proper earth ground point in this switch box? The n=0 is a mildly interesting edge case: Clearly a pointer that points to at least one valid byte could be used as the src or dest pointer to a call to memcpy(, 0). which would allow us to systematically observe what you are having. Does Counterspell prevent from any further spells being cast on a given turn? The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. 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 What methods/tools can be used to determine the cause so that you stop the exception from causing the progra. In the meantime, Im locking this thread. Null pointers should not be dereferenced. We. Is null check needed before calling instanceof? Please direct comments on this JSR to the Spec Lead (s) Team. What is pointed to should only be deleted if it was created with new. How to deal with "java.lang.OutOfMemoryError: Java heap space" error? How to use java.net.URLConnection to fire and handle HTTP requests, Why should Java 8's Optional not be used in arguments, sonarLint complains "Null pointers should not be dereferenced (squid:S2259)" despite that possibility being handled. SonarLint: A "NullPointerException" could be thrown; "getBody()" can return null. I'd guess null pointers are not valid, even though they point to 0 bytes. This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. The issue is: memcpy() and friends do not explicitly state that a null pointer is a valid pointer value, even if the number of bytes to copy is 0. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. 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. public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . At this point we define size as strlen(input_str) + 1. Whats the grammar of "For those whose stories they are"? Null pointer should not be dereferenced . Find centralized, trusted content and collaborate around the technologies you use most. Dereferencing a null pointer results in undefined behavior. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to bypass security measures. While the engine is in practice already able to explore code from other files if needed (relying solely on bytecode), we restrain this approach to a limited set of well-known methods from standard libraries, for which we know that behaviors are correctly produced. 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 (?,?,?,?,?,?,?,? Obviously the value of that pointer could have changed since the . ii. 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. I have a sonar alert on this call minRating.getRatgCaam(). At worst, it could expose debugging information that would be useful to an attacker or it could allow an Pointer members in structs are not checked. JCP version in use: 2.6. Automated Detection Null pointer dereferences can happen in path-dependent ways. Hi Andreas, Thanks for the feedback. If you write [ref], then a null pointer is not allowed, but if you write [unique], then a null pointer is permitted. Just because something is a pointer does not mean you should call delete . it could allow an attacker to bypass security measures. Do not dereference null pointers Created by Jeffrey Gennari, last modified by Jill Britton on Jan 18, 2023 Dereferencing a null pointer is undefined behavior. Using Kolmogorov complexity to measure difficulty of problems? It is useful to have a function with portable interface but platform-dependent implementation: extern bool invalid(const void *); If you preorder a special airline meal (e.g. NullPointerException is thrown when program attempts to use an object reference that has the null value. Description The program can potentially dereference a null pointer, thereby raising a NullPointerException. The result of calling such a helper function should be . IDE extension that lets you fix coding issues before they exist! And the semantics, as I said, are different. Why does Mister Mxyzptlk need to have a weakness in the comics? This compliant solution eliminates the null pointer deference by initializing sk to tun->sk following the null pointer check. There are many ways to resolve this. NULL vs Uninitialized pointer - An uninitialized pointer stores an undefined value. SonarQube null pointers should not be dereferenced on try/catch, Sonarcube :Null pointers should not be dereferenced, How do you get out of a corner when plotting yourself into a corner. Trying to understand how to get this basic Fourier Series. C# static code analysis: Null pointers should not be dereferenced Products In-IDE IDE extension that lets you fix coding issues before they exist! Search for vulnerabilities resulting from the violation of this rule on the CERT website. The standard will simply copy 0 byteswhich is essentially a no-op. NullPointerException is a RuntimeException. Batch split images vertically in half, sequentially numbering the output files, Recovering from a blunder I made while emailing a professor. Sonar is ok. Sonar can't determine that the helper method did the null validation. vegan) just to try it, does this inconvenience the caterers and staff? Trying to understand how to get this basic Fourier Series. Making statements based on opinion; back them up with references or personal experience. You need to benchmark. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. {"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. SonarQube - Null Pointer Dereference Issue java simonsirak (Simon Sirak) June 14, 2018, 1:18pm 1 Hi! 0 is a valid value as far as memcpy() is concerned, and malloc() has special language concerning malloc(0). Doing so will cause a NullReferenceException to be thrown. The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. ", 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". 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]. The value 0 for the number of bytes to copy is not what causes the UB, it's the null pointer value which triggers it. 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. Calls to extension methods are not reported because they can still operate on null values. When length is zero, it is probably unusable condition for this function. A common memory-leak idiom, is reallocating storage and assigning its address to a pointer that already points to allocated storage. Basically, yes. best, such an exception will cause abrupt program termination. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. context.RaiseException . We might set a pointer to null even if we are not freeing a object, simply to dissociate one object from another: tty_driver->tty = NULL; /* detach low level driver from the tty device */ On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. SIZE_MAX is the largest possible value that a size_t could take, so it is not possible to have anything larger than SIZE_MAX. raiseException() return, Sonar To learn more, see our tips on writing great answers. )}"); You can use Optional instead. Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. Finally, there is the matter of the compliant solution. Is it possible to rotate a window 90 degrees if it has the same length and width? I am a student implementing stack with singly linked list using C, following a book called Fundamentals of Data Structures in C.. Styling contours by colour and by line thickness in QGIS. 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]. The user_data pointer could be invalid in other ways, such as pointing to freed memory. After that, you call res.getBody() again. sometimes FP occurs. Note that it doesn't know how to check for non-heap, non-stack. 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. (C11, S7.24.2.1). In order to fix this, just do the following: If you are absolutely sure that res.getBody() stays null and is also not modified by another thread, you could also use a //NOSONAR comment in order to suppress the warning. minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). Hi @Michael! https://stackoverflow.com/questions/47534436/, https://stackoverflow.com/questions/47534436/, java - Jenkins groovy : Error: java. All rights are expressly reserved. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. Is the God of a monotheism necessarily omnipotent? SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. 11 Sep, 2006. 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. Two null pointers will always be equal to each other. When I added the not null validation as sonar suggest. I'd guess WG14 has considered these questions, but I haven't until now :). > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? The above check can't hurt, as I guess you could have a system with a 32-bit size_t that had a ton of memory and had some crazy banking/selector scheme with pointers. The purpose of a NULL pointer is not to cause a processor exception when it is dereferenced (although that is nice to have for debugging.) However there is no portable way to verify that the pointer is valid, other than checking for null. Alternate Terms Relationships - the incident has nothing to do with me; can I use this this way? But passing 0 to memcpy() is not one of them. This code also violates ERR33-C. Detect and handle standard library errors. If you call connect() function, it better do the connection, but failing simply because some ptr is NULL is not good behaviour -- failures should . (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). Is the God of a monotheism necessarily omnipotent? A pointer to null (the 0 memory address) should never be dereferenced/accessed. If you say [in] or [out] without a modifier, then the modifier defaults to the pointer_default for the enclosing class. What is null pointer exception in android. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. The method isNR(minRating) is a helper method that validate among other things, if the object minRating is null. It also reinforces the notion to the reader that any time you see arithmetic in an allocation expression, you need to think about corner-cases. res.getBody() == null || res.getBody().getServiceResult() == null). The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). Powered by Discourse, best viewed with JavaScript enabled. 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. The Clang Static Analyzer already has a checker to find the null pointer dereference in code, however it is not sufficient for higher abstractions such as C++ smart pointers or optionals. And if there is no pointer_default declaration, then the default default is ref. In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. 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. A reference to null should never be dereferenced/accessed. In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. When B is null, The control reaches inside the main if block only when length of A is 1. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? The issue arises when dereferenced pointers are used. 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. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. Batch split images vertically in half, sequentially numbering the output files, Difficulties with estimation of epsilon-delta limit proof, Minimising the environmental effects of my dyson brain. I don't need to do this validation again. Software Engineering Institute The problem is, I hope this code's result to be <5,3> and <9,6> BUT the console only shows me <5,3> and <9,3>. can have the value zero on a call to that function. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. What is generic pointer? (I think you cover that in a different rule.) How can this new ban on drag possibly be considered constitutional? It looks like a logic bug, which can cause a memory leaking. Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. to 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. But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. [4] What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Interactions/interfaces with C can't use references. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. @Tibor SonarQube version 5.6.6, IntelliJ SonarLint plugin 3.0.0.2041, Sonar: Null pointers should not be dereferenced, How Intuit democratizes AI development across teams through reusability. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. 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. A NULL pointer can be dereferenced when signatures are being verified on PKCS7 signed or signedAndEnveloped data. With their flexibility, void pointers also bring some constraints. Reports. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Consider the following scenario: you are asked to create a Java class MetaDisplay that contains a static void printTable(String r) method. SonarLint IntelliJ 4.0.0.2916 Java Rule 'Null pointers should not be dereferenced' I'm getting this fault in the next code when obj can't be null in any scenario. A bug can cause them never to be reassigned. Discover SonarLint SaaS Setup is effortless and analysis is automatic for most languages Discover SonarCloud Self-Hosted Fast, accurate analysis; enterprise scalability Discover SonarQube Secrets ABAP Powered by Discourse, best viewed with JavaScript enabled. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. Removing the check "exception != null" raises S2259 "Null pointers should not be dereferenced" on "throw exception". Things go fine now. 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. Depending on whether the pointer is valid (i.e. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. How can we let this pass? 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. Thanks for contributing an answer to Stack Overflow! Asking for help, clarification, or responding to other answers. (from res.getBody().getServiceResult() ). (/). A null pointer in this position causes the read system call to fail with -EINVAL ("Invalid argument"). sonarLint (3.2.) Instead use String.valueOf (object). Making statements based on opinion; back them up with references or personal experience. Yeah, I suspect once it's possible to allocate 2+gigs contiguously in amainstream install of a modern OS, we'll see a frenzy of new vulnerabilities come out. Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. At Check whether a String is not Null and not Empty. Thanks for contributing an answer to Stack Overflow! This is indeed a false positive because, at time of writing, the sonarqube java analyzer (version 4.2.1 at time of writing) does not support cross procedural analysis and so it is not able to determine that indeed, for the condition to be true, the value of minRating has to be non null. 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.. ncdu: What's going on with this second size column? Is there a single-word adjective for "having exceptionally strong moral principles"? Issues Components. Null pointer should not be dereferenced , Asking for help, clarification, or responding to other answers. Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. 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. rev2023.3.3.43278. Using Kolmogorov complexity to measure difficulty of problems? which version of SonarQube are you using? 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). An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. Thanks, David! Asking for help, clarification, or responding to other answers. I feel my situation is not as complicated. I added a comment to explain that SIZE_MAX is the limit of size_t. Im very new to sonar, is there a way to add methods to the whitelist? This engine is validating execution paths and checking for non-null values or null-check along the way, exploring all the possibilities. Avoid Returning null from Methods. I guess you could write a proposal to modify the C Standard, but our coding standard is meant to provide guidance for the existing language. Does it just mean failing to correctly check if a value is null? So the SIZE_MAX check was unnecessary. It means this is illegal: T* p = nullptr; T& r = *p; // illegal NOTE: Please do not email us saying the above works on your particular version of your particular compiler. 2008-2023 SonarSource S.A., Switzerland. 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. You do not have permission to delete messages in this group, Either email addresses are anonymous for this group or you need the view member email addresses permission to view the original message. 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. EXP34-C is a common consequence of ignoring function return values, but it is a distinct error, and can occur in other scenarios too. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. return p == NULL || (char *)p < &_etext; I have checked on multiple . Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. HTTP request redirections should not be open to forging attacks Deserialization should not be vulnerable to injection attacks Endpoints should not be vulnerable to reflected cross-site scripting (XSS) attacks "CoSetProxyBlanket" and "CoInitializeSecurity" should not be used Database queries should not be vulnerable to injection attacks 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. And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). Small typo nit: "such as if i t pointed to freed memory" meant to say "if it" instead (removing whitespace). There can be a null pointer type for each pointer type, such as a pointer to a character or a pointer to an integer, although this is . 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. Goal specifies the length of the array for a function. The same problem we will have with "Add at least one assertion to this test case." The null concept refers to the idea that a pointer can hold a special value that is not equal to another pointer. Doing so will cause a NullReferenceException to be thrown. 4500 Fifth Avenue Believing that dereferencing NULL shouldn't crash the system doesn't make it true. We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. That's true. Sonar detects that res.getBody() can be null when you do the check res.getBody()==null. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? 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). Making statements based on opinion; back them up with references or personal experience. Not the answer you're looking for?
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