Correct; a null pointer is not a valid pointer for the C library functions. Instead use String.valueOf (object). sonarlint, sonarLint (3.2.) it could allow an attacker to bypass security measures. Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. I doubt that "length" of zero is a valid parameter, and although there no copy, but we see memory allocation. Software Engineering Institute
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. However, memory allocation > functions such as kstrdup() may fail and returns NULL. This solution also ensures that theuser_data pointer is not null. positive S2637 in SonarQube 6.7.1 LTS, Sonar false positive, "change condition so that it does not always evaluate to true. 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 can we prove that the supernatural or paranormal doesn't exist? 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). Doing so will cause a NullReferenceException to be thrown. 1 Answer Sorted by: 1 Your code is ok. But no where in that particular idiom would a NULL pointer necessarily be deferenced. This issues is displayed by SonarQube. How to use Slater Type Orbitals as a basis functions in matrix method correctly? 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. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? Best to cite C11 s7.24.2.1 here: The memcpy function copies n characters from the object pointed to by s2 into the object pointed to by s1. This sounds indeed like a bug in the flow when an exception is raised. I have checked on multiple . Could I capture, and I would be able to glean much security information from the dump? Not the answer you're looking for? 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. Does Java have support for multiline strings? Doing so will cause a NullPointerException to be thrown. The fact that you can't pass a null (no object) with a reference parameter can be a reason to use a pointer instead. If you write [ref], then a null pointer is not allowed, but if you write [unique], then a null pointer is permitted. Finally, there is the matter of the compliant solution. When B is null, The control reaches inside the main if block only when length of A is 1. Sonar is ok. Sonar can't determine that the helper method did the null validation. Whats the grammar of "For those whose stories they are"? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, It is a false positive, but it might be a good idea not to do the, Sonar false-positive on rule: Null pointers should not be dereferenced, How Intuit democratizes AI development across teams through reusability. So we have to check all the arguments before performing any actions. This rule applies to all null pointers, regardless of which function returned them. If not, this might be a bug. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? I suggest that this topic needs to include calloc() and realloc() Refer to Linux man pages online for more enlightenment about malloc(), and friends. io.NotSerializableException : java. 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. Making statements based on opinion; back them up with references or personal experience. Is there a single-word adjective for "having exceptionally strong moral principles"? The result of calling such a helper function should be . The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). Dereferencing a null pointer can lead to a denial of service. public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . Please explain: Without this, we wont be able to help you. And if there is no pointer_default declaration, then the default default is ref. 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. Ticket opened : Thanks a lot for the minimalized reproducer ! 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). Extended Description NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions. . Why does Mister Mxyzptlk need to have a weakness in the comics? A reference to Nothing should never be dereferenced/accessed. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. java Doing so will at best cause abrupt program termination, without the This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. Thered be huge value in jumping onto the latest version of the ecosystem (notably SonarQube), and benefit from all latest analyzers (e.g. attacker to bypass security measures. Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. Batch split images vertically in half, sequentially numbering the output files, Recovering from a blunder I made while emailing a professor. The solution that I recommend is not work with null returns or variables on Java, try to avoid it. The chunkdata pointer is later used as a destination argument in a call to memcpy(), resulting in user-defined data overwriting memory starting at address 0. Goal Calls to extension methods are not reported because they can still operate on null values. Agreed. I think "res.getBody() == null" checks null first so it should go to return line, not reach to next if condition. versions used (SonarQube, Scanner, language analyzer) Likewise, pointers to freed memory are not valid. Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. http://blog.llvm.org/2011/05/what-every-c-programmer-should-know_14.html. The correct idiom is to only allocate storage if the pointer is currently NULL. 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. Connect and share knowledge within a single location that is structured and easy to search. We. context.RaiseException . Good question! Using Kolmogorov complexity to measure difficulty of problems? Doing so will cause a NullReferenceException to be thrown. That makes sense. On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. For example the following program doesn't compile. , NPE : null-, . Find centralized, trusted content and collaborate around the technologies you use most. Is null check needed before calling instanceof? . It does not point to any area of memory. extern char _etext; 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. At this point we define size as strlen(input_str) + 1. In multithreaded programs, null pointer dereferences can violate cache coherency policies and can cause resource leaks. However there is no portable way to verify that the pointer is valid, other than checking for null. (I think you cover that in a different rule.) the Java one). rev2023.3.3.43278. On such a call, a function that locates a character finds no occurrence, a function that compares two character sequences returns zero, and a function that copies characters copies zero characters. sonarlint complains that Additionally, if input_str is a null pointer, the call to strlen() dereferences a null pointer, also resulting in undefined behavior. What is a serialVersionUID and why should I use it? 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. Avoid Returning null from Methods. best, such an exception will cause abrupt program termination. It looks like a logic bug, which can cause a memory leaking. What is the point of Thrower's Bandolier? We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. If you preorder a special airline meal (e.g. Status: Dormant. Aaron:I suspect we are talking past each other. Does it just mean failing to correctly check if a value is null? Null pointers should not be dereferenced. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. There are many ways to resolve this. Software project. 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. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Reports. Accessing or modifying a null object's field. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. This topic was automatically closed 7 days after the last reply. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. which version of SonarQube are you using? Styling contours by colour and by line thickness in QGIS. Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. Explain about call by reference with an . Basically, yes. If malloc() fails, it returns a null pointer that is assigned to c_str. util.regex.Matcher, java - Swing .getParent() . When length is zero, it is probably unusable condition for this function. https://stackoverflow.com/questions/47534436/, https://stackoverflow.com/questions/47534436/, java - Jenkins groovy : Error: java. The null pointer check for writing or dereferencing should be a compiler flag or library setting. 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 (?,?,?,?,?,?,?,? 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). Recovering from a blunder I made while emailing a professor. 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. 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. In the meantime, Im locking this thread. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. A pointer to null (the 0 memory address) should never be dereferenced/accessed. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. 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. 4. In C, dereferencing a null pointer is undefined behavior. uninitialized reference-type class members. Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. very old code or C code being worked into c++ may have functions that expect the user to delete the data. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. 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. Pointer members in structs are not checked. PS: I also tried the code in android studio which uses Lint and got no warnings. Can you please start a new thread and be more explicit about the issue you are observing. in above code, That interpretation of the standard is not supported universally. When a variable is declared as being a pointer to type void, it is known as a generic pointer. 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?) Can I tell police to wait and call a lawyer when served with a search warrant? rev2023.3.3.43278. 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. To learn more, see our tips on writing great answers. 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. 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. When and how should I use a ThreadLocal variable? 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. Making statements based on opinion; back them up with references or personal experience. Find centralized, trusted content and collaborate around the technologies you use most. Phew, we're agreed here. So, this code should address the Sonar problem: You can also eliminate the null check using Optional