Just because something is a pointer does not mean you should call delete . Provide a self-contained reproducer (zipped project?) Just a few words about the rule now. Making statements based on opinion; back them up with references or personal experience. 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. Doing so will at best cause abrupt program termination, without the [4] Sonar detects that res.getBody() can be null when you do the check res.getBody()==null. , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. In C, dereferencing a null pointer is undefined behavior. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. In C# and Java, all reference types can point to null. The same problem we will have with "Add at least one assertion to this test case." > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. 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. 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. How do I align things in the following tabular environment? SonarQube Version 6.7.2 (build 37468) In the case of the ARM and XScale architectures, the 0x0 address is mapped in memory and serves as the exception vector table; consequently, dereferencing 0x0 did not cause an abnormal program termination. Ah, gotcha. When I scan with sonar-lint in idea, it seams white list is useful, but when use sonar-scanner, always FP, org.springframework.util.CollectionUtils#isEmpty Dereferencing > this null pointer may cause the kernel go wrong. And fwstr > is dereferenced in the following codes. The result of calling such a helper function should be . 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 SonarJava. I reordered that code example to do all the checks before allocations. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. When and how should I use a ThreadLocal variable? rev2023.3.3.43278. Does Counterspell prevent from any further spells being cast on a given turn? validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. Is there a single-word adjective for "having exceptionally strong moral principles"? Unfortunately, its actual state also has some limitations, like the one you are hitting here. . Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. How to use Slater Type Orbitals as a basis functions in matrix method correctly? Is it possible to rotate a window 90 degrees if it has the same length and width? That is only true if possibleNumbers contains no element.. BTW: none of these warnings are shown by . Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? SonarQube null pointers should not be dereferenced on try/catch, Sonarcube :Null pointers should not be dereferenced, How do you get out of a corner when plotting yourself into a corner. Why is there a voltage on my HDMI and coaxial cables? 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. . How do you ensure that a red herring doesn't violate Chekhov's gun? it could allow an attacker to bypass security measures. Since SIZE_MAX represents the largest possible object, the largest possible string would then be SIZE_MAX-1 characters long (excluding '\0'). Accessing or modifying a null object's field. Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. IMHO, the rule title should be changed to something less general. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. And if there is no pointer_default declaration, then the default default is ref. Basically, yes. 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]. Hi @Michael! 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. This solution also ensures that theuser_data pointer is not null. which would allow us to systematically observe what you are having. To learn more, see our tips on writing great answers. sonarLint (3.2.) What is a NullPointerException, and how do I fix it?,What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? It could be non-null the first time but not the second time, sonar does not know this. 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?) When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. Find centralized, trusted content and collaborate around the technologies you use most. This is indeed an obvious False Positive from the rule. sonarlint complains that . Connect and share knowledge within a single location that is structured and easy to search. (/). Im very new to sonar, is there a way to add methods to the whitelist? Status: Dormant. Dereferencing a null pointer results in undefined behavior. There are many ways to resolve this. sonarqube The fact that you can't pass a null (no object) with a reference parameter can be a reason to use a pointer instead. sonarlint, sonarLint (3.2.) Note that it doesn't know how to check for non-heap, non-stack. sonar-java. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. null(java.lang.NullPointerException) . 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. 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. Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. Two null pointers will always be equal to each other. How do I align things in the following tabular environment? Small typo nit: "such as if i t pointed to freed memory" meant to say "if it" instead (removing whitespace). 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. Off by one error: It is the third example. There are many ways to resolve this. NULL vs Uninitialized pointer - An uninitialized pointer stores an undefined value. Is it possible to create a concave light? Dereferencing a null pointer is undefined behavior. The idea is not to guarantee validity, but to catch a substantial number of problems that could occur. 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. What is the point of Thrower's Bandolier? NullPointerException is thrown when program attempts to use an object reference that has the null value. Trying to understand how to get this basic Fourier Series. In my experience, there are reasons to check for a NULL pointer other than dereferencing it. So the first execution of ValidateNumber inside the foreach works fine and valid is set to true.The second execution throws the exception and exception is set in the catch-Block.. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? 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. 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. Should trycatch go inside or outside a loop? I have checked on multiple . It also adds assertions to document that certain other pointers must not be null. When I added the not null validation as sonar suggest. 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 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. In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. 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. Its purpose is to serve as a special value for a pointer that could indicate a special condition in your program. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Thanks for the feedback. That interpretation of the standard is not supported universally. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. Using Kolmogorov complexity to measure difficulty of problems? Instead use String.valueOf (object). But even with this, the concerned object it tagged as a possible NullPointerException problem. 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. 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. Issues Components. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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. Recovering from a blunder I made while emailing a professor. PS: I also tried the code in android studio which uses Lint and got no warnings. 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. In the code, we check the not nullity with java.util.Objects.nonNull(). Pittsburgh, PA 15213-2612
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. 3.Null pointers should not be derefer enced/accessed. 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. return p == NULL || (char *)p < &_etext; How can we let this pass? Likewise, pointers to freed memory are not valid. Some Interesting Facts: 1) void pointers cannot be dereferenced. uninitialized reference-type class members. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. @Tibor SonarQube version 5.6.6, IntelliJ SonarLint plugin 3.0.0.2041, Sonar: Null pointers should not be dereferenced, How Intuit democratizes AI development across teams through reusability. https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx extern char _etext; I say "theoretical" because I have not successfully produced strings of this length in testing. Reports. Doing so will cause a NullReferenceException to be thrown. 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. If you preorder a special airline meal (e.g. ", 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". Why are physically impossible and logically impossible concepts considered separate in terms of probability? It is still a pointer though, to use it you just have to cast it to another kind of pointer first. When a variable is declared as being a pointer to type void, it is known as a generic pointer. The expected result here is solve the issue with sonarqube. 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. I believe in this case, either expression would work. PS: I also tried the code in android studio which uses Lint and got no warnings. I added a comment to explain that SIZE_MAX is the limit of size_t. C# static code analysis: Null pointers should not be dereferenced Products In-IDE IDE extension that lets you fix coding issues before they exist! Does it just mean failing to correctly check if a value is null? Why does Mister Mxyzptlk need to have a weakness in the comics? 1 Answer Sorted by: 1 Your code is ok. 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?) What is null pointer exception in android. Passing a null pointer tomemcpy() would produce undefined behavior, even if the number of bytes to copy were 0. Which @NotNull Java annotation should I use? 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. Thank you for clarifying your assertion until I understood it properly. The standard will simply copy 0 byteswhich is essentially a no-op. Explain about call by reference with an . It does not point to any area of memory. Thanks for contributing an answer to Stack Overflow! 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. Can I tell police to wait and call a lawyer when served with a search warrant? 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. java All rights are expressly reserved. In case the hash algorithm used for the signature is known to the OpenSSL library but the implementation of the hash algorithm is not available the digest initialization will fail. How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. After that, you call res.getBody() again. You can use Optional instead. On the command prompt, the same arguments work and the record is added in db but not when I call the stored procedure from inside java program CallableStatement insertStat = db_conn.prepareCall (" {call InsertCourses (?,?,?,?,?,?,?,? This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. . Which version of SonarJava plugin do you have? Trying to understand how to get this basic Fourier Series. Null pointers should not be dereferenced. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? For the time being, I would unfortunately recommend to mark as False Positive the issue. 11 Sep, 2006. positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced". 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). best, such an exception will cause abrupt program termination. I don't need to do this validation again. If not, this might be a bug. 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" Then we hit memcpy with length 0. Share Improve this answer Follow answered Oct 5, 2017 at 16:27 At Check whether a String is not Null and not Empty. You can compare a pointer with NULL to test for the special condition. 0 is a valid value as far as memcpy() is concerned, and malloc() has special language concerning malloc(0). And the semantics, as I said, are different. 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. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. context.RaiseException . This sounds indeed like a bug in the flow when an exception is raised. specifies the length of the array for a function. Connect and share knowledge within a single location that is structured and easy to search. The null pointer check for writing or dereferencing should be a compiler flag or library setting. SonarQube - Null Pointer Dereference Issue java simonsirak (Simon Sirak) June 14, 2018, 1:18pm 1 Hi! 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 These can be: Invoking a method from a null object. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. name result . So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). 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. At this point we define size as strlen(input_str) + 1. How to deal with "java.lang.OutOfMemoryError: Java heap space" error? A reference to Nothing should never be dereferenced/accessed. But when length of A is 1, the control never reaches the else block. which version of SonarQube are you using? I already tried to put ResponseEntity
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