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 To be precise, once length is changed to a size_t and cannot take negative values, it cannot have an invalid value. Not the answer you're looking for? }. 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. 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. Depending on whether the pointer is valid (i.e. Is the God of a monotheism necessarily omnipotent? Why is there a voltage on my HDMI and coaxial cables? (I think you cover that in a different rule.) I suppose there is a question of "Is a pointer that points to 0 bytes valid?" What is a serialVersionUID and why should I use it? Null pointers should not be dereferenced. public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . Write a semantic patch to nd cases where the result of calling kmalloc is dereferenced with no previous NULL pointer test. Off by one error: It is the third example. Connect and share knowledge within a single location that is structured and easy to search. When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. Null pointer should not be dereferenced . Aaron:I suspect we are talking past each other. You're in a company-managed project. How do I align things in the following tabular environment? Trying to understand how to get this basic Fourier Series. 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. () I suppose we can check that that is not null, but we cannot check that it is valid (in any portable way). Revert Update S2259: "Null pointer dereference" CFG should ignore expressions in Debug.Assert #397 Introduce means to not raise "Expression always true/false" on values that were checked with Debug.Assert. The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. I'd guess null pointers are not valid, even though they point to 0 bytes. 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" 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. There is no guarantee that subsequent invocations are returning the same value, thats why issue is raised. Now, you can find the list of whitelisted methods here. If malloc() fails, it returns a null pointer that is assigned to c_str. Check whether a String is not Null and not Empty. Unfortunately, its actual state also has some limitations, like the one you are hitting here. Styling contours by colour and by line thickness in QGIS. 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. "After the incident", I started to be more careful not to trip over things. Agreed. , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow Please explain: Without this, we wont be able to help you. Should trycatch go inside or outside a loop? PS: I also tried the code in android studio which uses Lint and got no warnings. 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. (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). java Please direct comments on this JSR to the Spec Lead (s) Team. - the incident has nothing to do with me; can I use this this way? NullPointerException is thrown when program attempts to use an object reference that has the null value. PS: I also tried the code in android studio which uses Lint and got no warnings. It looks like a logic bug, which can cause a memory leaking. This code also violates ERR33-C. Detect and handle standard library errors. 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. 3.7. Much like dereferencing a dangling (or wild) pointer leads to undefined behavior, dereferencing a null pointer also leads to undefined behavior. {"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. 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. And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). Now (sonarqube java analyzer version 4.3.0.7717) it's supported and works fine. Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. Is it possible to create a concave light? This likely means that youre on an ancient version of the Java analyzer. It is useful to have a function with portable interface but platform-dependent implementation: extern bool invalid(const void *); Is it possible to rotate a window 90 degrees if it has the same length and width? Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. Recovering from a blunder I made while emailing a professor. All content is copyright protected. )}"); 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. Then we hit memcpy with length 0. The fact that you can't pass a null (no object) with a reference parameter can be a reason to use a pointer instead. Im very new to sonar, is there a way to add methods to the whitelist? How can we prove that the supernatural or paranormal doesn't exist? rev2023.3.3.43278. the Java one). All rights are expressly reserved. ncdu: What's going on with this second size column? This issues is displayed by SonarQube. rev2023.3.3.43278. I have a sonar alert on this call minRating.getRatgCaam(). Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. 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. To create a custom null validation method declare an attribute with name ValidatedNotNullAttribute and mark the parameter that is Sonar is ok. Making statements based on opinion; back them up with references or personal experience. Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. 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. Rule squid:S2259 is based on a Symbolic Execution (SE) engine. Dereferencing a null pointer can lead to a denial of service. The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. The expected result here is solve the issue with sonarqube. 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. 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 topic was automatically closed 7 days after the last reply. Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines. positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, 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]. 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. The issue arises when dereferenced pointers are used. 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 . But what exactly does it mean to "dereference a null pointer"? This will normally lead to an unhandled error, resulting in a segmentation fault. Then the reading of the buffer via bstr_printf() will then look at the pointer to process the final output. This sounds indeed like a bug in the flow when an exception is raised. 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. When and how should I use a ThreadLocal variable? SonarJava Version 5.9.2 (build 16552). Is there a single-word adjective for "having exceptionally strong moral principles"? In C/C++ speak, 'dereferencing' simply means getting the object that a pointer . In C, dereferencing a null pointer is 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. isEmpty(Collection collection) 4500 Fifth Avenue
Correct; a null pointer is not a valid pointer for the C library functions. Obviously the value of that pointer could have changed since the . 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. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? In the simplest case, this function just returns the result of calling kmalloc. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Share Improve this answer Follow answered Oct 5, 2017 at 16:27 That is, sets equivalent to a proper subset via an all-structure-preserving bijection. On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. Does Counterspell prevent from any further spells being cast on a given turn? Thank you for clarifying your assertion until I understood it properly. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. static-code-analysis This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. Dereferencing a null pointer is undefined behavior. 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. Description The program can potentially dereference a null pointer, thereby raising a NullPointerException. 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. This solution also ensures that theuser_data pointer is not null. Could I capture, and I would be able to glean much security information from the dump? I don't need to do this validation again. If you try to access any member variables or methods with that variable, you are trying to dereference it. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Hello. But even with this, the concerned object it tagged as a possible NullPointerException problem. return p == NULL || (char *)p < &_etext; For the time being, I would unfortunately recommend to mark as False Positive the issue. SonarQube - Null Pointer Dereference Issue java simonsirak (Simon Sirak) June 14, 2018, 1:18pm 1 Hi! Software Engineering Institute
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. Is there a proper earth ground point in this switch box? It also adds assertions to document that certain other pointers must not be null. 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. Things go fine now. Its purpose is to serve as a special value for a pointer that could indicate a special condition in your program. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. There are other problems with this code, as is noted in the rule. You can use Optional instead. The null pointer check for writing or dereferencing should be a compiler flag or library setting. Do "superinfinite" sets exist? What does "Could not find or load main class" mean? 2008-2023 SonarSource S.A., Switzerland. vegan) just to try it, does this inconvenience the caterers and staff? extern char _etext; "After the incident", I started to be more careful not to trip over things. Not the answer you're looking for? int changed to size_t and if size_t parameter's is zero, allocate one word. If you call connect() function, it better do the connection, but failing simply because some ptr is NULL is not good behaviour -- failures should . IMHO, the rule title should be changed to something less general. Thered be huge value in jumping onto the latest version of the ecosystem (notably SonarQube), and benefit from all latest analyzers (e.g. What is null pointer exception in android. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. (/). 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]. It could be non-null the first time but not the second time, sonar does not know this. 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. If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? Since SIZE_MAX represents the largest possible object, the largest possible string would then be SIZE_MAX-1 characters long (excluding '\0'). In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. The final NCCE is actually more insidious than it seems at first. 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. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. You're in a company-managed project. specifies the length of the array for a function. What is the point of Thrower's Bandolier? Does a summoned creature play immediately after being summoned by a ready action? ", 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". 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 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. minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). How can I check before my flight that the cloud separation requirements in VFR flight rules are met? 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. 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. Can you please start a new thread and be more explicit about the issue you are observing. 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). Identify where the allocation occurs. rev2023.3.3.43278. Passing ownership of something also requires pointers. 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. Doing so will cause a NullPointerException to be thrown. 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. > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . I already tried to put ResponseEntity