Find centralized, trusted content and collaborate around the technologies you use most. That is why I explicitly check for this in my attempted solution. Trying to understand how to get this basic Fourier Series. rev2023.3.3.43278. As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. SonarJava. 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. 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. The approximation of the try catch flow is such that we consider an exception can be thrown just after the curly brace of the try. specifies the length of the array for a function. Likewise, pointers to freed memory are not valid. . Why are physically impossible and logically impossible concepts considered separate in terms of probability? 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. False-positives are pointed out in other SO posts (1 & 2), where nulls are involved across functions and procedures. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. Calls to extension methods are not reported because they can still operate on null values. I am a student implementing stack with singly linked list using C, following a book called Fundamentals of Data Structures in C.. Off by one error: It is the third example. You can use Optional instead. 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. 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?) Thanks for contributing an answer to Stack Overflow! Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? There are many ways to resolve this. Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. Whats the grammar of "For those whose stories they are"? To be precise, once length is changed to a size_t and cannot take negative values, it cannot have an invalid value. 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. This is indeed an obvious False Positive from the rule. Using platform-specific means (e.g. In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. To learn more, see our tips on writing great answers. Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines. which would allow us to systematically observe what you are having. Can you please start a new thread and be more explicit about the issue you are observing. New replies are no longer allowed. To learn more, see our tips on writing great answers. Issues Components. - the incident has nothing to do with me; can I use this this way? IDE extension that lets you fix coding issues before they exist! Connect and share knowledge within a single location that is structured and easy to search. This topic was automatically closed 7 days after the last reply. For example the following program doesn't compile. I suppose there is a question of "Is a pointer that points to 0 bytes valid?" Is there a proper earth ground point in this switch box? NULL vs Uninitialized pointer - An uninitialized pointer stores an undefined value. Pointer members in structs are not checked. This code also violates ERR33-C. Detect and handle standard library errors. Making statements based on opinion; back them up with references or personal experience. Cause we need throw our own Runtime Exception, well-known methods wont help. When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). Note that it doesn't know how to check for non-heap, non-stack. I have checked on multiple . This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. Finally my method is returning a response with value of restTemplate. Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. Just a few words about the rule now. Explain about call by reference with an . Null pointer should not be dereferenced . Aaron:I suspect we are talking past each other. 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. How to deal with "java.lang.OutOfMemoryError: Java heap space" error? But even with this, the concerned object it tagged as a possible NullPointerException problem. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? If you preorder a special airline meal (e.g. Reports. Interactions/interfaces with C can't use references. Doing so will at best cause abrupt program termination, without the 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. 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. Thanks, David! 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). Whoops, you're right. How do you ensure that a red herring doesn't violate Chekhov's gun? Does it just mean failing to correctly check if a value is null? How do you ensure that a red herring doesn't violate Chekhov's gun? Please explain: Without this, we wont be able to help you. Rule squid:S2259 is based on a Symbolic Execution (SE) engine. I would also guess that pointers that point to the one-past-the-end of an array are also invalid. Thanks for the feedback. vegan) just to try it, does this inconvenience the caterers and staff? There are many ways to resolve this. And fwstr > is dereferenced in the following codes. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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. In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. Can I tell police to wait and call a lawyer when served with a search warrant? 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 NullPointerException to be thrown. 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?) But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Obviously the value of that pointer could have changed since the . Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. Sonar is ok. Sonar can't determine that the helper method did the null validation. 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.) Its purpose is to serve as a special value for a pointer that could indicate a special condition in your program. That makes sense. What is null pointer exception in android. Does Counterspell prevent from any further spells being cast on a given turn? Is the God of a monotheism necessarily omnipotent? Why does the second compliant example permit using possibly-null pointers? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. I'd guess WG14 has considered these questions, but I haven't until now :). . Powered by Discourse, best viewed with JavaScript enabled. In the simplest case, this function just returns the result of calling kmalloc. "After the incident", I started to be more careful not to trip over things. These can be: Invoking a method from a null object. Which @NotNull Java annotation should I use? The idea is not to guarantee validity, but to catch a substantial number of problems that could occur. Because a null pointer does not point to a meaningful object, an attempt to dereference(i.e., access the data stored at that memory location) a null pointer usually (but not always) causes a run-time error or immediate program crash. Find centralized, trusted content and collaborate around the technologies you use most. 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. A bug can cause them never to be reassigned. 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. Why does Mister Mxyzptlk need to have a weakness in the comics? Additionally, if input_str is a null pointer, the call to strlen() dereferences a null pointer, also resulting in undefined behavior. Is there a single-word adjective for "having exceptionally strong moral principles"? Software Engineering Institute This engine is validating execution paths and checking for non-null values or null-check along the way, exploring all the possibilities. In the meantime, Im locking this thread. Im very new to sonar, is there a way to add methods to the whitelist? The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. 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 uninitialized reference-type class members. Things go fine now. I've changed it to say null pointer instead of invalid pointer. In the complaint version, I like to make source code checking a little quicker by putting parenthesizes around arguments to |= or &= as. Hello. When B is null, The control reaches inside the main if block only when length of A is 1. The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. 3.Null pointers should not be derefer enced/accessed. Void pointers cannot be dereferenced as any other pointer. It looks like a logic bug, which can cause a memory leaking. What does it mean that a reference must refer to an object, not a dereferenced null pointer? Sonar is ok. I would therefore assert that a platform whose memcpy() did anything besides a no-op when given n=0 and valid source/destination pointers was not C-standards-compliant. raiseException() return, Sonar On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. When length is zero, it is probably unusable condition for this function. What is a serialVersionUID and why should I use it? util.regex.Matcher, java - Swing .getParent() . Is there a single-word adjective for "having exceptionally strong moral principles"? The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. // <------- 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. You're in a company-managed project. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. 4500 Fifth Avenue It is still a pointer though, to use it you just have to cast it to another kind of pointer first. res.getBody() == null || res.getBody().getServiceResult() == 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. What sort of strategies would a medieval military use against a fantasy giant? That's true. At 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. 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.
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