I don't need to do this validation again. Using Kolmogorov complexity to measure difficulty of problems? ii. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? At worst, it could expose debugging information that would be useful to an attacker or it could allow an Then the reading of the buffer via bstr_printf() will then look at the pointer to process the final output. All rights are expressly reserved. My question is; is my solution incorrect? 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. 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. Solution 1, it looks like, today's solution tomorrow's problem. Making statements based on opinion; back them up with references or personal experience. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. That's true. A bug can cause them never to be reassigned. Off by one error: It is the third example. to 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. sonarlint, sonarLint (3.2.) To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Shouldn't the function check all pointers before dereferencing them or passing them to another function? This code also violates ERR33-C. Detect and handle standard library errors. How can this new ban on drag possibly be considered constitutional? Is it possible to rotate a window 90 degrees if it has the same length and width? (C11, S7.24.2.1). Void pointers cannot be dereferenced as any other pointer. 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. 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. Is there a single-word adjective for "having exceptionally strong moral principles"? Doing so will at best cause abrupt program termination, without the 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? Thus we should check > this kstrdup() operation. Ticket opened : Thanks a lot for the minimalized reproducer ! Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. By explicitly teaching the C++ standard class behaviors we can make the Analyzer to find more bugs related to modern C++ code. , NPE : null-, . What sort of strategies would a medieval military use against a fantasy giant? , . 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. 2008-2023 SonarSource S.A., Switzerland. which would allow us to systematically observe what you are having. 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. And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? I suppose we can check that that is not null, but we cannot check that it is valid (in any portable way). Using platform-specific means (e.g. Which @NotNull Java annotation should I use? 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" 4. "After the incident", I started to be more careful not to trip over things. Correct; a null pointer is not a valid pointer for the C library functions. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. which version of SonarQube are you using? 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.. The method takes a relation name r as input, executes the query "select * from r," and prints the result out in tabular format with the attribute names displayed in the table's header; the attribute names are displayed in the table's header. it could allow an attacker to bypass security measures. Alternate Terms Relationships What is a serialVersionUID and why should I use it? 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. 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. It does not point to any area of memory. Styling contours by colour and by line thickness in QGIS. (/). static-code-analysis SonarQube Version 6.7.2 (build 37468) 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. 0 is a valid value as far as memcpy() is concerned, and malloc() has special language concerning malloc(0). 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). Trying to understand how to get this basic Fourier Series. PS: I also tried the code in android studio which uses Lint and got no warnings. )}"); If you call connect() function, it better do the connection, but failing simply because some ptr is NULL is not good behaviour -- failures should . By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. By 'valid pointers' I mean that both src and dest pointers are not null and they both point to non-overlapping arrays containing at least n bytes each. Does Counterspell prevent from any further spells being cast on a given turn? Status: Dormant. 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. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. Not the answer you're looking for? SonarQube - Null Pointer Dereference Issue java simonsirak (Simon Sirak) June 14, 2018, 1:18pm 1 Hi! . Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. Agreed. Connect and share knowledge within a single location that is structured and easy to search. In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. 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. How to tell which packages are held back due to phased updates. After that, you call res.getBody() again. Extended Description NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions. 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. Why do academics stay as adjuncts for years rather than move around? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to . Powered by Discourse, best viewed with JavaScript enabled. False-positives are pointed out in other SO posts (1 & 2), where nulls are involved across functions and procedures. 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. 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. How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. Is there a single-word adjective for "having exceptionally strong moral principles"? Interactions/interfaces with C can't use references. Thanks for contributing an answer to Stack Overflow! All content is copyright protected. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? However, memory allocation > functions such as kstrdup() may fail and returns NULL. This sounds indeed like a bug in the flow when an exception is raised. Check whether a String is not Null and not Empty. If copying takes place between objects that overlap, the behavior is undefined. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, how to handle Sonarlint java:S2259 (Null pointers should not be dereferenced), How Intuit democratizes AI development across teams through reusability. I doubt that "length" of zero is a valid parameter, and although there no copy, but we see memory allocation. 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. What are the effects of exceptions on performance in Java? Is null check needed before calling instanceof? 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. At worst, it could expose debugging information that would be useful to an attacker, or https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx What methods/tools can be used to determine the cause so that you stop the exception from causing the progra. vegan) just to try it, does this inconvenience the caterers and staff? Using Kolmogorov complexity to measure difficulty of problems? The null pointer check for writing or dereferencing should be a compiler flag or library setting. Optimizers are optimizing based on this latitude and have been for years. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. I would also guess that pointers that point to the one-past-the-end of an array are also invalid. This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. isEmpty(Collection collection) (I think you cover that in a different rule.) 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. Trying to understand how to get this basic Fourier Series. The n=0 is a mildly interesting edge case: Clearly a pointer that points to at least one valid byte could be used as the src or dest pointer to a call to memcpy(, 0). Made code more compliant with other rules. In C/C++ speak, 'dereferencing' simply means getting the object that a pointer . How do you ensure that a red herring doesn't violate Chekhov's gun? The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. Java Specification Participation Agreement version in use: 2.0. It's a modular system with the . Obviously the value of that pointer could have changed since the . 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. Can I tell police to wait and call a lawyer when served with a search warrant? 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. Thanks for contributing an answer to Stack Overflow! Does Java have support for multiline strings? 1 Null pointers should not be dereferenced @CheckForNull String getName(){.} Just a few words about the rule now. 1 Answer Sorted by: 1 Your code is ok. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. In C, dereferencing a null pointer is undefined behavior. CWE-476: NULL Pointer Dereference: 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. can have the value zero on a call to that function. 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. I added a comment to explain that SIZE_MAX is the limit of size_t. 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. A reference to null should never be dereferenced/accessed. It's still illegal. 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. 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. 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. To learn more, see our tips on writing great answers. versions used (SonarQube, Scanner, language analyzer) Asking for help, clarification, or responding to other answers. I believe that dereferencing NULL should not crash the system, should not allow a write to a NULL pointer area, but should always set errno, If I am a hacker, could I trap a null failure that would force a memory dump. Thanks, David! 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. (from res.getBody().getServiceResult() ). We cannot understand how there could be a null pointer exception at the reported line. The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. Since you cannot have a variable of type void, the pointer will not point to any data and therefore cannot be dereferenced. For example the following program doesn't compile. It looks like a logic bug, which can cause a memory leaking. > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. And the semantics, as I said, are different. NullPointerException is thrown when program attempts to use an object reference that has the null value. The user_data pointer could be invalid in other ways, such as pointing to freed memory. rev2023.3.3.43278. 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. very old code or C code being worked into c++ may have functions that expect the user to delete the data. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. We have a false positive with the " Null pointers should not be dereferenced -squid:S2259" rule : We have a "NullPointerException" false positive for which we do not know how to solve it. Im currently using SonarQube version 5.6.6. better way to handle this is to store the result of method invocation in a variable. . 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. [4] positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced". 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.