null pointers should not be dereferenced

On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. When I added the not null validation as sonar suggest. Null pointers should not be dereferenced. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. What sort of strategies would a medieval military use against a fantasy giant? This compliant solution ensures that the pointer returned by png_malloc() is not null. How to tell which packages are held back due to phased updates. A null pointer in this position causes the read system call to fail with -EINVAL ("Invalid argument"). 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. Connect and share knowledge within a single location that is structured and easy to search. In my experience, there are reasons to check for a NULL pointer other than dereferencing it. Check whether a String is not Null and not Empty. This will normally lead to an unhandled error, resulting in a segmentation fault. attacker to bypass security measures. which version of SonarQube are you using? The issue arises when dereferenced pointers are used. How to deal with "java.lang.OutOfMemoryError: Java heap space" error? raiseException() return, Sonar "After the incident", I started to be more careful not to trip over things. Interactions/interfaces with C can't use references. very old code or C code being worked into c++ may have functions that expect the user to delete the data. 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.. ability to run any cleanup processes. Are there tables of wastage rates for different fruit and veg? A pointer is simply a variable that contains a memory address. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? If copying takes place between objects that overlap, the behavior is undefined. 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 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(). You can use Optional instead. It could be non-null the first time but not the second time, sonar does not know this. )}"); False fault 'Null pointers should not be dereferenced' using Optional The final NCCE is actually more insidious than it seems at first. rev2023.3.3.43278. Can I tell police to wait and call a lawyer when served with a search warrant? I believe in this case, either expression would work. 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. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. But when length of A is 1, the control never reaches the else block. 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?) It is useful to have a function with portable interface but platform-dependent implementation: extern bool invalid(const void *); 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. Original Java Specification Request (JSR) - Java Community Process Status: Dormant. Please explain: Without this, we wont be able to help you. Using Kolmogorov complexity to measure difficulty of problems? [JAVA] 3.9 - FP for S2259 Null pointers should not be dereferenced At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to . 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]. When B is null, The control reaches inside the main if block only when length of A is 1. 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). So Bar might not be initialized but then the last line of your example should not be evaluated in this case. My question is; is my solution incorrect? Making statements based on opinion; back them up with references or personal experience. Not the answer you're looking for? rev2023.3.3.43278. COMP-PROG-MODULE-5-6-REVIEWER.pdf - Pointers to string java But what exactly does it mean to "dereference a null pointer"? 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. 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. Yeah, I suspect once it's possible to allocate 2+gigs contiguously in amainstream install of a modern OS, we'll see a frenzy of new vulnerabilities come out. 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. I feel my situation is not as complicated. (C11, S7.24.2.1). When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . 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). I don't need to do this validation again. - the incident has nothing to do with me; can I use this this way? Thanks, David! It's a modular system with the . Cause we need throw our own Runtime Exception, well-known methods wont help. This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. Then we hit memcpy with length 0. In the meantime, Im locking this thread. Share Improve this answer Follow answered Oct 5, 2017 at 16:27 How to convert the address of a dereferenced pointer from C to C# Is the God of a monotheism necessarily omnipotent? 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. How to use Slater Type Orbitals as a basis functions in matrix method correctly? Is a PhD visitor considered as a visiting scholar? Null Pointers - Keil forum - Support forums - Arm Community 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. Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. Pointer is so confusing : Stack with singly linked list in C - Stack C static code analysis: Null pointers should not be dereferenced Pointers in C Explained - They're Not as Difficult - freeCodeCamp.org Is null check needed before calling instanceof? It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. Connect and share knowledge within a single location that is structured and easy to search. Sonar violation: Null pointers should not be dereferenced #7459 - GitHub EXP01-J. Do not use a null in a case where an object is required In the complaint version, I like to make source code checking a little quicker by putting parenthesizes around arguments to |= or &= as. There is no guarantee that subsequent invocations are returning the same value, thats why issue is raised. All content is copyright protected. 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. strongSwan - strongSwan Vulnerability (CVE-2023-26463) If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? Whoops, you're right. After that, you call res.getBody() again. Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. Removing the check "exception != null" raises S2259 "Null pointers should not be dereferenced" on "throw exception". 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. [RSPEC-2259] - Jira Consider the following scenario: you are asked to create a Java class MetaDisplay that contains a static void printTable(String r) method. 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. Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. Connect and share knowledge within a single location that is structured and easy to search. 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. Possible fix: Assign a valid address to the pointer in all branches of the conditional statement.. Pointer can point to dynamically allocated memory. LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) Thanks for contributing an answer to Stack Overflow! Now, you can find the list of whitelisted methods here. 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. 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. So, this code should address the Sonar problem: You can also eliminate the null check using Optional>, like: Even I don't recommend this, you can just check the null responseDto without any use of Optional: Thanks for contributing an answer to Stack Overflow! I have checked on multiple . As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. Does a summoned creature play immediately after being summoned by a ready action? Could I capture, and I would be able to glean much security information from the dump? assert(!invalid(p)); // or whatever, bool invalid(const void *p) { We. Null Pointer Exception In Java - GeeksforGeeks - A computer science SonarLint: A "NullPointerException" could be thrown; "getBody()" can return null. which would allow us to systematically observe what you are having. Not the answer you're looking for? Finally, there is the matter of the compliant solution. If not, this might be a bug. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy.

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