(C11, S7.24.2.1). Unlike reference types, pointer types are not tracked by the default garbage . All content is copyright protected. 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. )}"); Software project. Does Counterspell prevent from any further spells being cast on a given turn? If you call connect() function, it better do the connection, but failing simply because some ptr is NULL is not good behaviour -- failures should . At best, such an exception will cause abrupt program termination. 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. sonarlint complains that Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. Software project. What is generic pointer? The return value from strchr() is often NULL, but the dev might know that a specific strchr() function call will not return NULL. Connect and share knowledge within a single location that is structured and easy to search. I don't need to do this validation again. There are other problems with this code, as is noted in the rule. The same problem we will have with "Add at least one assertion to this test case." The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. Can I tell police to wait and call a lawyer when served with a search warrant? What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? raiseException() return, Sonar null(java.lang.NullPointerException) . void *pointerVariableName = NULL; Since they are very general in nature, they are also known as generic pointers. Making statements based on opinion; back them up with references or personal experience. Finally, there is the matter of the compliant solution. If not, this might be a bug. How do you ensure that a red herring doesn't violate Chekhov's gun? 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. In this noncompliant code example, input_str is copied into dynamically allocated memory referenced by c_str. The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). 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.) In the meantime, Im locking this thread. rev2023.3.3.43278. This topic was automatically closed 7 days after the last reply. To learn more, see our tips on writing great answers. 11 Sep, 2006. It is still a pointer though, to use it you just have to cast it to another kind of pointer first. This likely means that youre on an ancient version of the Java analyzer. 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 C, dereferencing a null pointer is undefined behavior. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Using platform-specific means (e.g. If copying takes place between objects that overlap, the behavior is undefined. Trying to understand how to get this basic Fourier Series. 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). sonarLint (3.2.) Issues Components. 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?" 1 Null pointers should not be dereferenced @CheckForNull String getName(){.} The final NCCE is actually more insidious than it seems at first. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. In Java, a special null value can be assigned to an object reference. Find centralized, trusted content and collaborate around the technologies you use most. 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. sonarlint, sonarLint (3.2.) 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. 2008-2023 SonarSource S.A., Switzerland. context.RaiseException . The null pointer check for writing or dereferencing should be a compiler flag or library setting. 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. can have the value zero on a call to that function. Obviously the value of that pointer could have changed since the . Can you please start a new thread and be more explicit about the issue you are observing. Made code more compliant with other rules. The solution that I recommend is not work with null returns or variables on Java, try to avoid it. 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 . If malloc() fails, it returns a null pointer that is assigned to c_str. 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. Sonar is ok. isEmpty(Map map) Is there a single-word adjective for "having exceptionally strong moral principles"? Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? 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. Phew, we're agreed here. 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. How do you ensure that a red herring doesn't violate Chekhov's gun? In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. Is it possible to rotate a window 90 degrees if it has the same length and width? Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. 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. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to . Not the answer you're looking for? This engine is validating execution paths and checking for non-null values or null-check along the way, exploring all the possibilities. 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. Making statements based on opinion; back them up with references or personal experience. While the engine is in practice already able to explore code from other files if needed (relying solely on bytecode), we restrain this approach to a limited set of well-known methods from standard libraries, for which we know that behaviors are correctly produced. Im having trouble understanding your problem. 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). Possible fix: Assign a valid address to the pointer in all branches of the conditional statement.. Pointer can point to dynamically allocated memory. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. SonarQube Version 6.7.2 (build 37468) To learn more, see our tips on writing great answers. When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? And fwstr > is dereferenced in the following codes. 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. SonarJava Version 5.9.2 (build 16552). Your code needs to do something about the possible NullPointerException when some exception is caught, because in this scenario the responseDto will be null. Check whether a String is not Null and not Empty. {"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. return p == NULL || (char *)p < &_etext; . 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. And if there is no pointer_default declaration, then the default default is ref. You're in a company-managed project. Sonar is ok. Sonar can't determine that the helper method did the null validation. https://stackoverflow.com/questions/47534436/, https://stackoverflow.com/questions/47534436/, java - Jenkins groovy : Error: java. 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. Trying to understand how to get this basic Fourier Series. Not the answer you're looking for? This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. Hi @Michael! . 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. 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. Solution 1, it looks like, today's solution tomorrow's problem. I added a comment to explain that SIZE_MAX is the limit of size_t. Since SIZE_MAX represents the largest possible object, the largest possible string would then be SIZE_MAX-1 characters long (excluding '\0'). How can I check before my flight that the cloud separation requirements in VFR flight rules are met? Description The program can potentially dereference a null pointer, thereby raising a NullPointerException. . 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. SonarJava. 3.7. If you write [ref], then a null pointer is not allowed, but if you write [unique], then a null pointer is permitted. 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. - the incident has nothing to do with me; can I use this this way? Likewise, pointers to freed memory are not valid. All rights are expressly reserved. Why are physically impossible and logically impossible concepts considered separate in terms of probability? Making statements based on opinion; back them up with references or personal experience. 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]. Extended Description NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions. vegan) just to try it, does this inconvenience the caterers and staff? I would also guess that pointers that point to the one-past-the-end of an array are also invalid. How can we prove that the supernatural or paranormal doesn't exist? assert(!invalid(p)); // or whatever, bool invalid(const void *p) { What sort of strategies would a medieval military use against a fantasy giant? 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. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. Optimizers are optimizing based on this latitude and have been for years. A bug can cause them never to be reassigned. 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. 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. That makes sense. validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. sometimes FP occurs. 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. Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. After that, you call res.getBody() again. Using Kolmogorov complexity to measure difficulty of problems? Believing that dereferencing NULL shouldn't crash the system doesn't make it true. }. 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. extern char _etext; Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. 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?) Which version of SonarJava plugin do you have? 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. In the simplest case, this function just returns the result of calling kmalloc. But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. Correct; a null pointer is not a valid pointer for the C library functions. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? Status: Dormant. Rule squid:S2259 is based on a Symbolic Execution (SE) engine. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. It also adds assertions to document that certain other pointers must not be null. How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. Connect and share knowledge within a single location that is structured and easy to search. ROSE does not handle cases where an allocation is assigned to an lvalue that is not a variable (such as a struct member or C++ function call returning a reference), Finds instances where a pointer is checked against NULL and then later dereferenced, Identifies functions that can return a null pointer but are not checked, Identifies code that dereferences a pointer and then checks the pointer against NULL, Can find the instances where NULL is explicitly dereferenced or a pointer is checked againstNULL but then dereferenced anyway. In C# and Java, all reference types can point to null. 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. Thered be huge value in jumping onto the latest version of the ecosystem (notably SonarQube), and benefit from all latest analyzers (e.g. 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.
