This solution also ensures that theuser_data pointer is not null. We resolved it by adding our tools path in the white list, and repackaging it. These can be: Invoking a method from a null object. NullPointerException is thrown when program attempts to use an object reference that has the null value. Null pointer should not be dereferenced . (C11, S7.24.2.1). Please explain: Without this, we wont be able to help you. There is no legitimate reason to dereference a null pointer unless you on a rare system that maps page zero (or you intend your program to crash). Is a PhD visitor considered as a visiting scholar? Using Kolmogorov complexity to measure difficulty of problems? Is it possible to create a concave light? When you have a variable of non-primitive type, it is a reference to an object. Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. 11 Sep, 2006. How do I align things in the following tabular environment? In order to fix this, just do the following: BodyType body=res.getBody (); if (body == null || body.getServiceResult () == null) { return; } You can then even reuse body after that. How can we let this pass? 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. 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. it could allow an attacker to bypass security measures. Find centralized, trusted content and collaborate around the technologies you use most. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? 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. ncdu: What's going on with this second size column? I think that checking for user_data being NULL would be an improvement to the CS so long as there is an explicit mention that user_data being NULL is invalid even if length == 0. 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). sonarqube Which @NotNull Java annotation should I use? Issues Components. The solution that I recommend is not work with null returns or variables on Java, try to avoid it. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. I added an assertion to that compliant code example. Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. The standard will simply copy 0 byteswhich is essentially a no-op. I feel my situation is not as complicated. And fwstr > is dereferenced in the following codes. In Java, a special null value can be assigned to an object reference. JCP version in use: 2.6. But even with this, the concerned object it tagged as a possible NullPointerException problem. Explain about call by reference with an . How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. In the simplest case, this function just returns the result of calling kmalloc. 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>. And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx It's a modular system with the . However, memory allocation > functions such as kstrdup() may fail and returns NULL. public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . 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. sometimes FP occurs. I suggest that this topic needs to include calloc() and realloc() Refer to Linux man pages online for more enlightenment about malloc(), and friends. As for copy vs pointer/reference - it depends. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. The solution that I recommend is not work with null returns or variables on Java, try to avoid it. It is useful to have a function with portable interface but platform-dependent implementation: extern bool invalid(const void *); Now, you can find the list of whitelisted methods here. Interactions/interfaces with C can't use references. This sounds indeed like a bug in the flow when an exception is raised. The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). Which version of SonarJava plugin do you have? After that, you call res.getBody() again. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. All content is copyright protected. We can not disable any rule, sonar do validation in "Sonar way" (actual name of profile :) ), so we will need to mark them "Wont fix" each time it appear again in new code. 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 . I think "res.getBody() == null" checks null first so it should go to return line, not reach to next if condition. 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. Cause we need throw our own Runtime Exception, well-known methods wont help. You can use Optional instead. {"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. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. It could be non-null the first time but not the second time, sonar does not know this. Im very new to sonar, is there a way to add methods to the whitelist? Styling contours by colour and by line thickness in QGIS. I have a sonar alert on this call minRating.getRatgCaam(). In some situations, however, dereferencing a null pointer can lead to the execution of arbitrary code [Jack 2007,van Sprundel 2006]. You can use Optional instead. Null pointer should not be dereferenced , So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). Just a few words about the rule now. SonarLint: A "NullPointerException" could be thrown; "getBody()" can return null. Accessing or modifying a null object's field. We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. If malloc() fails, it returns a null pointer that is assigned to c_str. That makes sense. See the "Null pointer checks may be optimized away more aggressively" section inhttps://gcc.gnu.org/gcc-4.9/porting_to.htmlas an example with one common implementation. Carnegie Mellon University 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. (/). ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. When B is null, The control reaches inside the main if block only when length of A is 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. 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. 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. res.getBody() == null || res.getBody().getServiceResult() == null). What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? 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. 3.7. Reports. [4] Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. I have checked on multiple . Thered be huge value in jumping onto the latest version of the ecosystem (notably SonarQube), and benefit from all latest analyzers (e.g. IDE extension that lets you fix coding issues before they exist! The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. Is there a proper earth ground point in this switch box? When and how should I use a ThreadLocal variable? 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. Dereferencing > this null pointer may cause the kernel go wrong. can have the value zero on a call to that function. Because null pointer dereferencing is undefined behavior, the compiler (GCC in this case) can optimize away the if (!tun) check because it is performed after tun->sk is accessed, implying that tun is non-null. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. 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). 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. . To learn more, see our tips on writing great answers. Off by one error: It is the third example. Check whether a String is not Null and not Empty. http://blog.llvm.org/2011/05/what-every-c-programmer-should-know_14.html. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, It is a false positive, but it might be a good idea not to do the, Sonar false-positive on rule: Null pointers should not be dereferenced, How Intuit democratizes AI development across teams through reusability. 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. At The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. The user_data pointer could be invalid in other ways, such as pointing to freed memory. I believe in this case, either expression would work. It is still a pointer though, to use it you just have to cast it to another kind of pointer first. . 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. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. False-positives are pointed out in other SO posts (1 & 2), where nulls are involved across functions and procedures. 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. Description The program can potentially dereference a null pointer, thereby raising a NullPointerException. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. I don't need to do this validation again. Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. 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. Can I tell police to wait and call a lawyer when served with a search warrant? When and how should I use a ThreadLocal variable? positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced". Unfortunately the problem is much more complex, and generally unsolvable within standard C. Consider the following example: There's no way f can check whether x points into valid memory or not. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. When I added the not null validation as sonar suggest. The final NCCE is actually more insidious than it seems at first. It's still illegal. Since you cannot have a variable of type void, the pointer will not point to any data and therefore cannot be dereferenced. In multithreaded programs, null pointer dereferences can violate cache coherency policies and can cause resource leaks. Why do academics stay as adjuncts for years rather than move around? rev2023.3.3.43278. Why is there a voltage on my HDMI and coaxial cables? Correct; a null pointer is not a valid pointer for the C library functions. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. Does Java have support for multiline strings? How to tell which packages are held back due to phased updates. So you can declare a string t and then add characters to the string with a plus sign : t += 'a'; The code you are having issue with is just moving the pointer to the next character which the foreach is already doing. This compliant solution ensures that both input_str andthe pointer returned by malloc() are not null: This noncompliant code example is from a version of drivers/net/tun.c and affects Linux kernel 2.6.30 [Goodin 2009]: The sk pointer is initialized to tun->sk before checking if tun is a null pointer. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. The expected result here is solve the issue with sonarqube. Thanks for contributing an answer to Stack Overflow! At worst, it could expose debugging information that would be useful to an attacker, or