Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. When a variable is declared as being a pointer to type void, it is known as a generic pointer. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. I was fixing some issues gathered by SonarQube when I stumbled upon the following issue: SonarQube violation: Possible null pointer dereference in ___ due to return value of called method, This error was found in the following code: else if (foo.list().length > 0) { }, I attempted to resolve this by rewriting as: else if (null != foo.list() && foo.list().length > 0) { }, foo is an instance of the File class in Java, and is directly instantiated through new File(). SonarJava Version 5.9.2 (build 16552). Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. At best, such an exception will cause abrupt program termination. I suppose there is a question of "Is a pointer that points to 0 bytes valid?" 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. When B is null, The control reaches inside the main if block only when length of A is 1. I have checked on multiple . assert(!invalid(p)); // or whatever, bool invalid(const void *p) { I believe that dereferencing NULL should not crash the system, should not allow a write to a NULL pointer area, but should always set errno, If I am a hacker, could I trap a null failure that would force a memory dump. , . Asking for help, clarification, or responding to other answers. ncdu: What's going on with this second size column? Cause we need throw our own Runtime Exception, well-known methods wont help. How can we prove that the supernatural or paranormal doesn't exist? The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. As for copy vs pointer/reference - it depends. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. The result of calling such a helper function should be . 4500 Fifth Avenue
So Bar might not be initialized but then the last line of your example should not be evaluated in this case. Dereferencing a null pointer results in undefined behavior. Appropriate typecasting is necessary. In this noncompliant code example, input_str is copied into dynamically allocated memory referenced by c_str. Your code needs to do something about the possible NullPointerException when some exception is caught, because in this scenario the responseDto will be null. We. 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 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. Can I tell police to wait and call a lawyer when served with a search warrant? Thanks, David! validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. Then we hit memcpy with length 0. I say "theoretical" because I have not successfully produced strings of this length in testing. attacker to bypass security measures. it could allow an attacker to bypass security measures. Should trycatch go inside or outside a loop? Shouldn't the function check all pointers before dereferencing them or passing them to another function? Mutually exclusive execution using std::atomic? After that, you call res.getBody() again. Null pointer should not be dereferenced . And if there is no pointer_default declaration, then the default default is ref. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. . This sounds indeed like a bug in the flow when an exception is raised. Then the reading of the buffer via bstr_printf() will then look at the pointer to process the final output. Powered by Discourse, best viewed with JavaScript enabled. Description: This JSR will work to develop standard annotations (such as @NonNull) that can be applied to Java programs to assist tools that detect software defects. Issues Components. A nonnegative return value represents the number of bytes successfully read (the return value is a "signed size" type, usually the native integer type for the target platform). Issues Components. static-code-analysis Instead use String.valueOf (object). Optimizers are optimizing based on this latitude and have been for years. 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. Connect and share knowledge within a single location that is structured and easy to search. 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. Off by one error: It is the third example. Can you please start a new thread and be more explicit about the issue you are observing. The only potential null is the return value of list(). Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. Is there a proper earth ground point in this switch box? We resolved it by adding our tools path in the white list, and repackaging it. In the code, we check the not nullity with java.util.Objects.nonNull(). return p == NULL || (char *)p < &_etext; 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 */ 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. Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines. Please explain: Without this, we wont be able to help you. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. Removing the check "exception != null" raises S2259 "Null pointers should not be dereferenced" on "throw exception". sonarLint (3.2.) 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. We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. The alert is related to the sonar rule : Null pointers should not be dereferenced. 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. 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. This compliant solution ensures that the pointer returned by png_malloc() is not null. 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Status: Dormant. I'd guess WG14 has considered these questions, but I haven't until now :). 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 That makes sense. 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). Is null check needed before calling instanceof? (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) Dereferencing a null pointer is undefined behavior, typically abnormal program termination. can have the value zero on a call to that function. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? The correct idiom is to only allocate storage if the pointer is currently NULL. However, memory allocation > functions such as kstrdup() may fail and returns NULL. positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced". }. context.RaiseException , (/) My below code where I'm calling a stored procedure is giving a null pointer exception. 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. In the simplest case, this function just returns the result of calling kmalloc. Hello. This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. Trying to understand how to get this basic Fourier Series. For example the following program doesn't compile. I suggest that this topic needs to include calloc() and realloc() Refer to Linux man pages online for more enlightenment about malloc(), and friends. Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. 3.7. How do you ensure that a red herring doesn't violate Chekhov's gun? 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. At this point we define size as strlen(input_str) + 1. The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). res.getBody() == null || res.getBody().getServiceResult() == null). Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. My main problem is because I'm doing a restTemplate.exchange with try-catch and declaring a variable with null value before the clause try and then using it inside the try. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? A pointer to null (the 0 memory address) should never be dereferenced/accessed. rev2023.3.3.43278. Many platforms can support testing for those also. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. PS: I also tried the code in android studio which uses Lint and got no warnings. Rule squid:S2259 is based on a Symbolic Execution (SE) engine. A non-null but invalid pointer passed to memcpy() can indeed cause undefined behavior, but that is not the issue in the noncompliant codethe pointer will either be valid or null. I added a comment to explain that SIZE_MAX is the limit of size_t. In Java, a special null value can be assigned to an object reference. Much like dereferencing a dangling (or wild) pointer leads to undefined behavior, dereferencing a null pointer also leads to undefined behavior. The method isNR(minRating) is a helper method that validate among other things, if the object minRating is null. A reference to null should never be dereferenced/accessed. (C11, S7.24.2.1). 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. How do I align things in the following tabular environment? 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?) That's true. ", 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". 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. very old code or C code being worked into c++ may have functions that expect the user to delete the data. To learn more, see our tips on writing great answers. rev2023.3.3.43278. extern char _etext; I already tried to put ResponseEntity
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