null pointers should not be dereferencedsecondary containment requirements osha

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 ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . Rule squid:S2259 is based on a Symbolic Execution (SE) engine. Things go fine now. Issues Components. rev2023.3.3.43278. There is a missing check for the return value from . This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. rev2023.3.3.43278. which version of SonarQube are you using? In the simplest case, this function just returns the result of calling kmalloc. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? A reference to null should never be dereferenced/accessed. , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow Is it possible to create a concave light? 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. The null pointer check for writing or dereferencing should be a compiler flag or library setting. [PATCH 1/3] usb: ucsi: Fix NULL pointer deref in ucsi_connector_change() Isn't easier just to check valid range of length? 3.7. NULL POINTERS SHOULD NOT BE DEREFERENCED - jobhuntley.com We cannot understand how there could be a null pointer exception at the reported line. name result . Find centralized, trusted content and collaborate around the technologies you use most. At What is null pointer exception in android. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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. When B is null, The control reaches inside the main if block only when length of A is 1. This code also violates ERR33-C. Detect and handle standard library errors. - the incident has nothing to do with me; can I use this this way? That makes sense. I don't need to do this validation again. return p == NULL || (char *)p < &_etext; SonarQube Version 6.7.2 (build 37468) However, memory allocation > functions such as kstrdup() may fail and returns NULL. In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. I feel my situation is not as complicated. io.NotSerializableException : java. This is indeed an obvious False Positive from the rule. The only potential null is the return value of list(). An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. java Issues Components. validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. How do I align things in the following tabular environment? Correct; a null pointer is not a valid pointer for the C library functions. Ticket opened : Thanks a lot for the minimalized reproducer ! What does it mean that a reference must refer to an object, not a dereferenced null pointer? sonarqube 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). It looks like a logic bug, which can cause a memory leaking. 5.2 Part 2 Sometimes a helper function is de ned to perform the memory allocation. How do you ensure that a red herring doesn't violate Chekhov's gun? - the incident has nothing to do with me; can I use this this way? At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to . Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. If you write [ref], then a null pointer is not allowed, but if you write [unique], then a null pointer is permitted. A bug can cause them never to be reassigned. 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. Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. When B is null, The control reaches inside the main if block only when length of A is 1. Thanks for the feedback. Dereferencing a null pointer results in undefined behavior. 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. So we have to check all the arguments before performing any actions. can have the value zero on a call to that function. Clearly the standard enumerates 1 case of undefined behavior, but makes no special mention of n=0. 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. The expected result here is solve the issue with sonarqube. [SONARJAVA-2808] - Jira - SonarSource You need to benchmark. I suppose we can check that that is not null, but we cannot check that it is valid (in any portable way). We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. 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). Null pointers should not be dereferenced #1155 - GitHub , . Is there a proper earth ground point in this switch box? Thus we should check > this kstrdup() operation. The alert is related to the sonar rule : Null pointers should not be dereferenced. At this point we define size as strlen(input_str) + 1. 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. Write a semantic patch to nd cases where the result of calling kmalloc is dereferenced with no previous NULL pointer test. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, S2259: Null pointers should not be dereferenced, find the list of whitelisted methods here, Rule java:S2259: False-positive NullPointerException bug logged when variable is null-checked by an imported method, What is the issue you are observing, in details, What version of SonarSource products you are using, as well as the version of SonarJava. This rule applies to all null pointers, regardless of which function returned them. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Explain about call by reference with an . Using Kolmogorov complexity to measure difficulty of problems? My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? Thanks for contributing an answer to Stack Overflow! Trying to understand how to get this basic Fourier Series. C static code analysis: Null pointers should not be dereferenced C static code analysis Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C code All rules 311 Vulnerability 13 Bug 74 Security Hotspot 18 Code Smell 206 Quick Fix 14 Tags "memset" should not be used to delete sensitive data Vulnerability For example the following program doesn't compile. strongSwan - strongSwan Vulnerability (CVE-2023-26463) Im currently using SonarQube version 5.6.6. better way to handle this is to store the result of method invocation in a variable. And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). There are many ways to resolve this. Why void pointer cannot be dereferenced? Explained by Sharing Culture U1 merged - It is a great text book for learning about linux devices. (/). Two null pointers will always be equal to each other. Making statements based on opinion; back them up with references or personal experience. Is null check needed before calling instanceof? 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. Pointer Arithmetic in c - Unit - 4 1. Define pointer. Explain about the 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. 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. How to deal with "java.lang.OutOfMemoryError: Java heap space" error? Powered by Discourse, best viewed with JavaScript enabled. The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. Pittsburgh, PA 15213-2612 But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. ncdu: What's going on with this second size column? context.RaiseException , (/) Not the answer you're looking for? 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>. Find centralized, trusted content and collaborate around the technologies you use most. 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. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). At worst, it could expose debugging information that would be useful to an attacker or it could allow an There is no guarantee that subsequent invocations are returning the same value, thats why issue is raised. . Small typo nit: "such as if i t pointed to freed memory" meant to say "if it" instead (removing whitespace). assert(!invalid(p)); // or whatever, bool invalid(const void *p) { raiseException() return, Sonar Phew, we're agreed here. I could've fixed this by changing else to else if (B != null && B.length == 1), but doing so rewards me with warning "condition(B != null && B.length == 1) is always true". 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 How can we prove that the supernatural or paranormal doesn't exist? Since SIZE_MAX represents the largest possible object, the largest possible string would then be SIZE_MAX-1 characters long (excluding '\0'). See "Clever Attack Exploits Fully-Patched Linux Kernel" [Goodin 2009] for an example of a code execution exploit that resulted from a null pointer dereference. Finally, there is the matter of the compliant solution. If you try to access any member variables or methods with that variable, you are trying to dereference it. Since you cannot have a variable of type void, the pointer will not point to any data and therefore cannot be dereferenced. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Then we hit memcpy with length 0. The null concept refers to the idea that a pointer can hold a special value that is not equal to another pointer. Solution 1, it looks like, today's solution tomorrow's problem. PS: I also tried the code in android studio which uses Lint and got no warnings. But what exactly does it mean to "dereference a null pointer"? And fwstr > is dereferenced in the following codes. uninitialized reference-type class members. Using Kolmogorov complexity to measure difficulty of problems? How can I check before my flight that the cloud separation requirements in VFR flight rules are met? extern char _etext; Sonar detects that res.getBody() can be null when you do the check res.getBody()==null. Making statements based on opinion; back them up with references or personal experience. When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. In the meantime, Im locking this thread. That is why I explicitly check for this in my attempted solution. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 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. very old code or C code being worked into c++ may have functions that expect the user to delete the data. 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 to fix int cannot be dereferenced? Explained by Sharing Culture 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. There are other problems with this code, as is noted in the rule. This likely means that youre on an ancient version of the Java analyzer. C# static code analysis: HTTP responses should not be vulnerable to All content is copyright protected. With their flexibility, void pointers also bring some constraints. Why is there a voltage on my HDMI and coaxial cables? In the complaint version, I like to make source code checking a little quicker by putting parenthesizes around arguments to |= or &= as. JCP version in use: 2.6. rev2023.3.3.43278. How to convert the address of a dereferenced pointer from C to C# Software project. 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. But when length of A is 1, the control never reaches the else block. You can use Optional instead. Not the answer you're looking for? 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 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]. That interpretation of the standard is not supported universally. Connect and share knowledge within a single location that is structured and easy to search. PS: I also tried the code in android studio which uses Lint and got no warnings. 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. 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. By explicitly teaching the C++ standard class behaviors we can make the Analyzer to find more bugs related to modern C++ code. Null pointer - Wikipedia void *pointerVariableName = NULL; Since they are very general in nature, they are also known as generic pointers. 2008-2023 SonarSource S.A., Switzerland. 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. So the SIZE_MAX check was unnecessary. Can I tell police to wait and call a lawyer when served with a search warrant? Appropriate typecasting is necessary. Styling contours by colour and by line thickness in QGIS. (I think you cover that in a different rule.) COMP-PROG-MODULE-5-6-REVIEWER.pdf - Pointers to string )}"); (C11, S7.24.2.1). As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. How can we let this pass? 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. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. 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. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. (from res.getBody().getServiceResult() ). Does Counterspell prevent from any further spells being cast on a given turn? But no where in that particular idiom would a NULL pointer necessarily be deferenced. 1 Answer Sorted by: 1 Your code is ok. See the "Null pointer checks may be optimized away more aggressively" section inhttps://gcc.gnu.org/gcc-4.9/porting_to.htmlas an example with one common implementation.

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