This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature.
PDF Fourth Coccinelle Workshop { Exercises 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. Hi Andreas, Thanks for the feedback. This engine is validating execution paths and checking for non-null values or null-check along the way, exploring all the possibilities. raiseException() return, Sonar which would allow us to systematically observe what you are having. This sounds indeed like a bug in the flow when an exception is raised. NULL vs Void Pointer - Null pointer is a value, while void pointer is a type. 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. Description The program can potentially dereference a null pointer, thereby raising a NullPointerException. NULL vs Uninitialized pointer - An uninitialized pointer stores an undefined value. Not the answer you're looking for? Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. Because null pointer dereferencing is UB, the if (!tun) check can be elided entirely by the optimizer (since the tun->sk implies that tun must be non-null). 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. Are there tables of wastage rates for different fruit and veg?
squid:S2259 : A "NullPointerException" could be thrown; "dc" is I've changed it to say null pointer instead of invalid pointer.
Sonar violation: Null pointers should not be dereferenced #7459 - GitHub io.NotSerializableException : java. At worst, it could expose debugging information that would be useful to an attacker or it could allow an Find centralized, trusted content and collaborate around the technologies you use most. Explain about call by reference with an . (C11, S7.24.2.1). How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Sonar false-positive on rule: Null pointers should not be dereferenced, Null Pointer Dereference issue not detected when the pointer is returned by another function. Goal The result of calling such a helper function should be . Search for vulnerabilities resulting from the violation of this rule on the CERT website. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. res.getBody() == null || res.getBody().getServiceResult() == null). At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to bypass security measures. Seems the analizer don't recognice the logic with the funcional object Optional. 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. In C/C++ speak, 'dereferencing' simply means getting the object that a pointer . To create a custom null validation method declare an attribute with name ValidatedNotNullAttribute and mark the parameter that is In this noncompliant code example, input_str is copied into dynamically allocated memory referenced by c_str. 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. 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. Clearly the standard enumerates 1 case of undefined behavior, but makes no special mention of n=0. Using platform-specific means (e.g. These can be: Invoking a method from a null object.
Callable statement giving Null Pointer Exception - Oracle Forums Find null smart pointer dereferences with the Clang Static Analyzer Java Specification Participation Agreement version in use: 2.0. The value 0 for the number of bytes to copy is not what causes the UB, it's the null pointer value which triggers it. What methods/tools can be used to determine the cause so that you stop the exception from causing the progra. Avoid Returning null from Methods. Much like dereferencing a dangling (or wild) pointer leads to undefined behavior, dereferencing a null pointer also leads to undefined behavior. Im having trouble understanding your problem. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. S2259: Null pointers should not be dereferenced java tsubasa (Jiaoyang Ma) January 11, 2019, 6:57am 1 versions used (SonarQube, Scanner, language analyzer) SonarQube Version 6.7.2 (build 37468) SonarJava Version 5.9.2 (build 16552) minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). I'd guess null pointers are not valid, even though they point to 0 bytes. We really appreciate your help. Making statements based on opinion; back them up with references or personal experience. java Removing the check "exception != null" raises S2259 "Null pointers should not be dereferenced" on "throw exception".
1. Introduction - Understanding and Using C Pointers [Book] sonar-java. This compliant solution eliminates the null pointer deference by initializing sk to tun->sk following the null pointer check. You can use Optional instead. Find centralized, trusted content and collaborate around the technologies you use most. A pointer to null (the 0 memory address) should never be dereferenced/accessed. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? How can we prove that the supernatural or paranormal doesn't exist? 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. Doing so will cause a NullPointerException to be thrown. IDE extension that lets you fix coding issues before they exist!
When should pointers be checked for NULL in C? Null pointers should not be dereferenced #1155 - GitHub 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. How can we let this pass? Connect and share knowledge within a single location that is structured and easy to search. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. The standard will simply copy 0 byteswhich is essentially a no-op. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. In C, dereferencing a null pointer is undefined behavior. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. best, such an exception will cause abrupt program termination. I have a sonar alert on this call minRating.getRatgCaam(). The test was added to catch the possibly theoretical situation where the length of input_str was somehow the maximum size for size_t, and adding one to this size in the malloc expression (to allocated space for the trailing null byte) results in an integer overflow. This code also violates ERR33-C. Detect and handle standard library errors. 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. 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 (?,?,?,?,?,?,?,? When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). I feel my situation is not as complicated.
NullPointerException is thrown when program attempts to use an object reference that has the null value. 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. Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. At best, such an exception will cause abrupt program termination. Unlike reference types, pointer types are not tracked by the default garbage . It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). 4500 Fifth Avenue
Finally my method is returning a response with value of restTemplate. 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 versions used (SonarQube, Scanner, language analyzer) 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]. To be precise, once length is changed to a size_t and cannot take negative values, it cannot have an invalid value. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. 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. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. One could argue that all code examples would be redundant with the first pair. With their flexibility, void pointers also bring some constraints. The return value from strchr() is often NULL, but the dev might know that a specific strchr() function call will not return NULL. Correct; a null pointer is not a valid pointer for the C library functions. Thus we should check > this kstrdup() operation. Obviously the value of that pointer could have changed since the . 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>. It looks like a logic bug, which can cause a memory leaking. Powered by Discourse, best viewed with JavaScript enabled. 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. How do you ensure that a red herring doesn't violate Chekhov's gun? Connect and share knowledge within a single location that is structured and easy to search. Dereferencing > this null pointer may cause the kernel go wrong. And fwstr > is dereferenced in the following codes. This sounds indeed like a bug in the flow when an exception is raised.
Handling Java NullPointerException and Best Practices - HowToDoInJava Pointers in C Explained - They're Not as Difficult - freeCodeCamp.org You can compare a pointer with NULL to test for the special condition. Why do academics stay as adjuncts for years rather than move around? SonarJava Version 5.9.2 (build 16552). 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. Does a summoned creature play immediately after being summoned by a ready action? 2008-2023 SonarSource S.A., Switzerland.
Null pointer - Wikipedia context.RaiseException . Finally, there is the matter of the compliant solution. Null pointer should not be dereferenced . Passing ownership of something also requires pointers. ", 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". We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. To learn more, see our tips on writing great answers. It means this is illegal: T* p = nullptr; T& r = *p; // illegal NOTE: Please do not email us saying the above works on your particular version of your particular compiler. This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. 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. I'd guess WG14 has considered these questions, but I haven't until now :).
), NPD.CHECK.CALL.MIGHTNPD.CHECK.CALL.MUSTNPD.CHECK.MIGHTNPD.CHECK.MUSTNPD.CONST.CALLNPD.CONST.DEREFNPD.FUNC.CALL.MIGHTNPD.FUNC.CALL.MUSTNPD.FUNC.MIGHTNPD.FUNC.MUSTNPD.GEN.CALL.MIGHTNPD.GEN.CALL.MUSTNPD.GEN.MIGHTNPD.GEN.MUSTRNPD.CALLRNPD.DEREF, 45 D, 123 D, 128 D, 129 D, 130 D, 131 D, 652 S, Checks for use of null pointers (rule partially covered).
NULL POINTERS SHOULD NOT BE DEREFERENCED - jobhuntley.com What is the point of Thrower's Bandolier? We.
SonarQube null pointers should not be dereferenced on try/catch If not, this might be a bug. That makes sense. I say "theoretical" because I have not successfully produced strings of this length in testing.
CWE - CWE-476: NULL Pointer Dereference (4.10) - Mitre Corporation static-code-analysis
C# static code analysis: Null pointers should not be dereferenced My main problem is because I'm doing a restTemplate.exchange with try-catch and declaring a variable with null value before the clause try and then using it inside the try. 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. Sonar is ok. Sonar can't determine that the helper method did the null validation. 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. can have the value zero on a call to that function. 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. PS: I also tried the code in android studio which uses Lint and got no warnings. When and how should I use a ThreadLocal variable? I added a comment to explain that SIZE_MAX is the limit of size_t. Recovering from a blunder I made while emailing a professor. Pointer members in structs are not checked. Then the reading of the buffer via bstr_printf() will then look at the pointer to process the final output. Reports.
Original Java Specification Request (JSR) - Java Community Process 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, This error was found in the following code: else if (foo.list().length > 0) { }, I attempted to resolve this by rewriting as: else if (null != foo.list() && foo.list().length > 0) { }, foo is an instance of the File class in Java, and is directly instantiated through new File(). Ah, gotcha.
Analysis of Haiku Operating System (BeOS Family) by PVS-Studio. Part 1 [PATCH v2] vsprintf: Do not have bprintf dereference pointers Please direct comments on this JSR to the Spec Lead (s) Team. // <------- 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. ii. String *x, y; X is a pointer to a string, Y is a string & = address of variable/ operator || referencing operator * = value of address || dereferencing operator Pointers = stores memory address as its variables NULL pointer = a constant with a value of zero defined || assigned to null Void pointer = a pointer that is not associated with any data types New operator = denotes a request for . After that, you call res.getBody() again. Alternate Terms Relationships Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. There is no guarantee that subsequent invocations are returning the same value, thats why issue is raised. If you preorder a special airline meal (e.g. positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced". Appropriate typecasting is necessary. Interactions/interfaces with C can't use references. How do you ensure that a red herring doesn't violate Chekhov's gun? The solution that I recommend is not work with null returns or variables on Java, try to avoid it. The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. Your assertion is not backed by the wording in the standard, nor by common implementer understanding. When I added the not null validation as sonar suggest.
9.7 Null pointers - Learn C++ - LearnCpp.com Null - All content is copyright protected. 4. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). rev2023.3.3.43278. Things go fine now. There are many ways to resolve this. IMHO, the rule title should be changed to something less general. Making statements based on opinion; back them up with references or personal experience. Thanks for contributing an answer to Stack Overflow! Thered be huge value in jumping onto the latest version of the ecosystem (notably SonarQube), and benefit from all latest analyzers (e.g. Not the answer you're looking for? This likely means that youre on an ancient version of the Java analyzer. The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. When and how should I use a ThreadLocal variable? Likewise, pointers to freed memory are not valid. Note that it doesn't know how to check for non-heap, non-stack.
C static code analysis: Null pointers should not be dereferenced It is useful to have a function with portable interface but platform-dependent implementation: extern bool invalid(const void *); name result . Is it possible to rotate a window 90 degrees if it has the same length and width? So we have to check all the arguments before performing any actions. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Is there a single-word adjective for "having exceptionally strong moral principles"? 1 Null pointers should not be dereferenced @CheckForNull String getName(){.} sonarlint complains that JCP version in use: 2.6. 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 Believing that dereferencing NULL shouldn't crash the system doesn't make it true. That interpretation of the standard is not supported universally. If copying takes place between objects that overlap, the behavior is undefined. Extended Description NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions. You're in a company-managed project. What is a serialVersionUID and why should I use it? This is indeed a false positive because, at time of writing, the sonarqube java analyzer (version 4.2.1 at time of writing) does not support cross procedural analysis and so it is not able to determine that indeed, for the condition to be true, the value of minRating has to be non null. return p == NULL || (char *)p < &_etext; This topic was automatically closed 7 days after the last reply. It is still a pointer though, to use it you just have to cast it to another kind of pointer first. So the SIZE_MAX check was unnecessary. The null pointer check for writing or dereferencing should be a compiler flag or library setting. The alert is related to the sonar rule : Null pointers should not be dereferenced. Asking for help, clarification, or responding to other answers. sometimes FP occurs. I doubt that "length" of zero is a valid parameter, and although there no copy, but we see memory allocation. I would also guess that pointers that point to the one-past-the-end of an array are also invalid. Do "superinfinite" sets exist? vegan) just to try it, does this inconvenience the caterers and staff? Shouldn't the function check all pointers before dereferencing them or passing them to another function? It does not point to any area of memory. Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. This code also violates ERR33-C. Detect and handle standard library errors. EXP34-C is a common consequence of ignoring function return values, but it is a distinct error, and can occur in other scenarios too.