A pointer is simply a variable that contains a memory address. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? ), Does not guess that return values from malloc(), strchr(), etc., can be NULL (The return value from malloc() is NULL only if there is OOMo and the dev might not care to handle that. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. Connect and share knowledge within a single location that is structured and easy to search. I think "res.getBody() == null" checks null first so it should go to return line, not reach to next if condition. How to use Slater Type Orbitals as a basis functions in matrix method correctly? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. 5.2 Part 2 Sometimes a helper function is de ned to perform the memory allocation. There is a missing check for the return value from . 1 Answer Sorted by: 1 Your code is ok. Im currently using SonarQube version 5.6.6. better way to handle this is to store the result of method invocation in a variable. We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. Cause we need throw our own Runtime Exception, well-known methods wont help. Obviously the value of that pointer could have changed since the . Agreed. C static code analysis: Null pointers should not be dereferenced C static code analysis Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C code All rules 311 Vulnerability 13 Bug 74 Security Hotspot 18 Code Smell 206 Quick Fix 14 Tags "memset" should not be used to delete sensitive data Vulnerability Then the reading of the buffer via bstr_printf() will then look at the pointer to process the final output. Correct; a null pointer is not a valid pointer for the C library functions. 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. 11 Sep, 2006. I have a sonar alert on this call minRating.getRatgCaam(). An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. Carnegie Mellon University Please explain: Without this, we wont be able to help you. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. Reports. So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). These can be: Invoking a method from a null object. Optimizers are optimizing based on this latitude and have been for years. Is there a proper earth ground point in this switch box? Does it just mean failing to correctly check if a value is null? What methods/tools can be used to determine the cause so that you stop the exception from causing the progra. (from res.getBody().getServiceResult() ). Do "superinfinite" sets exist? Using Kolmogorov complexity to measure difficulty of problems? Goal Why does the second compliant example permit using possibly-null pointers? But even with this, the concerned object it tagged as a possible NullPointerException problem. This topic was automatically closed 7 days after the last reply. 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. All content is copyright protected. I don't need to do this validation again. Software project. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, SonarQube null pointers should not be dereferenced on try/catch, How Intuit democratizes AI development across teams through reusability. 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. A reference to null should never be dereferenced/accessed. 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 As for copy vs pointer/reference - it depends. Is it possible to create a concave light? 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?) Trying to understand how to get this basic Fourier Series. Provide a self-contained reproducer (zipped project?) Are there tables of wastage rates for different fruit and veg? That is why I explicitly check for this in my attempted solution. 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" 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. 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). Ah, gotcha. java 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. 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 Here is our source code: Sign in to download full-size image 3.Null pointers should not be derefer enced/accessed. 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. Alternate Terms Relationships 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Is it possible to create a concave light? Thank you for clarifying your assertion until I understood it properly. How can we let this pass? A value is checked here to see whether it is null, but this value can't be null because it was previously dereferenced and if it were null a null pointer exception would have occurred at the earlier dereference. (/). This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. If the pointer is not NULL, see if the assignment occurs only in a branch of a conditional statement.Investigate when that branch does not execute. 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. positive S2637 in SonarQube 6.7.1 LTS, Sonar false positive, "change condition so that it does not always evaluate to true. With their flexibility, void pointers also bring some constraints. 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. Find centralized, trusted content and collaborate around the technologies you use most. 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. Styling contours by colour and by line thickness in QGIS. If you preorder a special airline meal (e.g. SonarQube - Null Pointer Dereference Issue java simonsirak (Simon Sirak) June 14, 2018, 1:18pm 1 Hi! sometimes FP occurs. isEmpty(Collection collection) 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 Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . How can this new ban on drag possibly be considered constitutional? You can use Optional instead. 4500 Fifth Avenue 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. SonarLint: A "NullPointerException" could be thrown; "getBody()" can return null. If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? Why is there a voltage on my HDMI and coaxial cables? 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 common memory-leak idiom, is reallocating storage and assigning its address to a pointer that already points to allocated storage. Im having trouble understanding your problem. (C11, S7.24.2.1). Some Interesting Facts: 1) void pointers cannot be dereferenced. void *pointerVariableName = NULL; Since they are very general in nature, they are also known as generic pointers. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. - the incident has nothing to do with me; can I use this this way? 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. But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. The method isNR(minRating) is a helper method that validate among other things, if the object minRating is null. But what exactly does it mean to "dereference a null pointer"? Minimising the environmental effects of my dyson brain. The standard will simply copy 0 byteswhich is essentially a no-op. 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. In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. What sort of strategies would a medieval military use against a fantasy giant? Shouldn't the function check all pointers before dereferencing them or passing them to another function? This sounds indeed like a bug in the flow when an exception is raised. There are many ways to resolve this. Doing so will cause a NullReferenceException to be thrown. I already tried to put ResponseEntity responseDto inside my try clause assigning and returning the respective value but its mandatory to return something out the try/catch. Powered by Discourse, best viewed with JavaScript enabled. But no where in that particular idiom would a NULL pointer necessarily be deferenced. 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.) A reference to null should never be dereferenced/accessed. 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. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. My below code where I'm calling a stored procedure is giving a null pointer exception. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to bypass security measures. it could allow an attacker to bypass security measures. validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. The alert is related to the sonar rule : Null pointers should not be dereferenced. A null pointer in this position causes the read system call to fail with -EINVAL ("Invalid argument"). Is there a single-word adjective for "having exceptionally strong moral principles"? The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . Note that it doesn't know how to check for non-heap, non-stack. 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. But when length of A is 1, the control never reaches the else block. As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. Null pointers should not be dereferenced. JCP version in use: 2.6. The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. Pointer members in structs are not checked. This issues is displayed by SonarQube. rev2023.3.3.43278. To learn more, see our tips on writing great answers. which would allow us to systematically observe what you are having. For example the following program doesn't compile. 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. Passing ownership of something also requires pointers. In the meantime, Im locking this thread. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. null(java.lang.NullPointerException) . Thus we should check > this kstrdup() operation. Removing the check "exception != null" raises S2259 "Null pointers should not be dereferenced" on "throw exception". Trying to understand how to get this basic Fourier Series. A pointer to null (the 0 memory address) should never be dereferenced/accessed. io.NotSerializableException : java. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) 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. The 4gig boundary will probably be important too with unsigned int in LP64, but since size_t will be 64-bit, there will have to be some truncation that compilers will be able to warn on.