10 Mar, 2023

null pointers should not be dereferenced

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[PATCH 1/3] usb: ucsi: Fix NULL pointer deref in ucsi_connector_change() Software project. JCP version in use: 2.6. This engine is validating execution paths and checking for non-null values or null-check along the way, exploring all the possibilities. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. The standard will simply copy 0 byteswhich is essentially a no-op. The idea is not to guarantee validity, but to catch a substantial number of problems that could occur. [PATCH] drm_edid-load: Fix a missing-check bug in drivers/gpu/drm/drm What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? 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 ", Eclipse - Sonar S2629 possible false positive with new String, SonarQube null pointers should not be dereferenced on try/catch, getTextContent() through "Null pointers should not be dereferenced". Dereferencing a null pointer is undefined behavior. For example the following program doesn't compile. The final NCCE is actually more insidious than it seems at first. 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. That is only true if possibleNumbers contains no element.. BTW: none of these warnings are shown by . SonarQube null pointers should not be dereferenced on try/catch Isn't easier just to check valid range of length? To learn more, see our tips on writing great answers. SonarQube - Null Pointer Dereference Issue - Sonar Community In the simplest case, this function just returns the result of calling kmalloc. Accessing or modifying a null object's field. sonarlint, sonarLint (3.2.) Powered by Discourse, best viewed with JavaScript enabled. Dereferencing a null pointer can lead to a denial of service. FindBugs CORRECTNESS - Carnegie Mellon University EXP34-C. Do not dereference null pointers - Confluence Void pointers cannot be dereferenced as any other pointer. vegan) just to try it, does this inconvenience the caterers and staff? Why do academics stay as adjuncts for years rather than move around? At worst, it could expose debugging information that would be useful to an attacker, or 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". 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>. In C# and Java, all reference types can point to null. In some situations, however, dereferencing a null pointer can lead to the execution of arbitrary code [Jack 2007,van Sprundel 2006]. sonarLint (3.2.) 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. Connect and share knowledge within a single location that is structured and easy to search. How to fix int cannot be dereferenced? Explained by Sharing Culture 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. Is there a proper earth ground point in this switch box? If you write [ref], then a null pointer is not allowed, but if you write [unique], then a null pointer is permitted. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? 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. Minimising the environmental effects of my dyson brain. (/). This issues is displayed by SonarQube. Callable statement giving Null Pointer Exception - Oracle Forums Null pointer should not be dereferenced . return p == NULL || (char *)p < &_etext; By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. At this point we define size as strlen(input_str) + 1. 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. How do I align things in the following tabular environment? , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 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. U1 merged - It is a great text book for learning about linux devices. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. 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 (?,?,?,?,?,?,?,? The user_data pointer could be invalid in other ways, such as pointing to freed memory. Analysis of Haiku Operating System (BeOS Family) by PVS-Studio. Part 1 SonarJava. When I scan with sonar-lint in idea, it seams white list is useful, but when use sonar-scanner, always FP, org.springframework.util.CollectionUtils#isEmpty Is it suspicious or odd to stand by the gate of a GA airport watching the planes? 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. A null pointer in this position causes the read system call to fail with -EINVAL ("Invalid argument"). Whats the grammar of "For those whose stories they are"? Check whether a String is not Null and not Empty. 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). For the time being, I would unfortunately recommend to mark as False Positive the issue. References, C++ FAQ The correct idiom is to only allocate storage if the pointer is currently NULL. This compliant solution ensures that the pointer returned by png_malloc() is not null. That noncompliant code example (it's currently the 3rd) came from the Linux kernel, whose source is publicly available. 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. With their flexibility, void pointers also bring some constraints. Thanks for contributing an answer to Stack Overflow! 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. Small typo nit: "such as if i t pointed to freed memory" meant to say "if it" instead (removing whitespace). String *x, y; X is a pointer to a string, Y is a string & = address of variable/ operator || referencing operator * = value of address || dereferencing operator Pointers = stores memory address as its variables NULL pointer = a constant with a value of zero defined || assigned to null Void pointer = a pointer that is not associated with any data types New operator = denotes a request for . Aaron:I suspect we are talking past each other. Hello. Is null check needed before calling instanceof? Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. I believe in this case, either expression would work. 11 Sep, 2006. attacker to bypass security measures. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Is there a proper earth ground point in this switch box? Pointers in C Explained - They're Not as Difficult - freeCodeCamp.org Does Java have support for multiline strings? Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . The solution that I recommend is not work with null returns or variables on Java, try to avoid it. Null pointer - Wikipedia This is a matter of style, and also following code walkthrough. Thus we should check > this kstrdup() operation. 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. https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx Thanks for the feedback. Its purpose is to serve as a special value for a pointer that could indicate a special condition in your program. I feel my situation is not as complicated. Instead use String.valueOf (object). > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. Additionally, if input_str is a null pointer, the call to strlen() dereferences a null pointer, also resulting in undefined behavior. assert(!invalid(p)); // or whatever, bool invalid(const void *p) { And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). 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. When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. Find null smart pointer dereferences with the Clang Static Analyzer Does Counterspell prevent from any further spells being cast on a given turn? It's a modular system with the . Why does the second compliant example permit using possibly-null pointers? When you have a variable of non-primitive type, it is a reference to an object. C# static code analysis: HTTP responses should not be vulnerable to Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. Im having trouble understanding your problem. You're in a company-managed project. Identify where the allocation occurs. res.getBody() == null || res.getBody().getServiceResult() == null). Phew, we're agreed here. Appropriate typecasting is necessary. 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. {"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. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. }. specifies the length of the array for a function. And if there is no pointer_default declaration, then the default default is ref. 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. (C11, S7.24.2.1). 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. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. Reference vs dereference pointers in arguments C++/C // <------- reported violation: NullPointerException might be thrown as 'bar' is nullable here, https://jira.sonarsource.com/browse/SONARJAVA-1490, https://groups.google.com/d/msgid/sonarqube/4752a999-246e-42c2-bbdc-8a44a5564ce9%40googlegroups.com. S2259: Null pointers should not be dereferenced java tsubasa (Jiaoyang Ma) January 11, 2019, 6:57am 1 versions used (SonarQube, Scanner, language analyzer) SonarQube Version 6.7.2 (build 37468) SonarJava Version 5.9.2 (build 16552) minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). Status: Dormant. That makes sense. How to get rid of NullPointerException - freeCodeCamp.org Is the God of a monotheism necessarily omnipotent? In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. 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. When I added the not null validation as sonar suggest. Null pointers should not be dereferenced #1155 - GitHub extern char _etext; 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. To learn more, see our tips on writing great answers. It could be non-null the first time but not the second time, sonar does not know this. util.regex.Matcher, java - Swing .getParent() . Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. This is indeed an obvious False Positive from the rule. [SONARJAVA-2808] - Jira - SonarSource SonarQube Version 6.7.2 (build 37468) Do not dereference null pointers Created by Jeffrey Gennari, last modified by Jill Britton on Jan 18, 2023 Dereferencing a null pointer is undefined behavior. How can we prove that the supernatural or paranormal doesn't exist? A reference to Nothing should never be dereferenced/accessed. OpenSSL Releases Security Update - NHS Digital The fact that you can't pass a null (no object) with a reference parameter can be a reason to use a pointer instead. Null Dereference | OWASP Foundation False-positives are pointed out in other SO posts (1 & 2), where nulls are involved across functions and procedures. Search for vulnerabilities resulting from the violation of this rule on the CERT website. 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. sonarlint complains that I'd guess WG14 has considered these questions, but I haven't until now :). EXP01-J. Do not use a null in a case where an object is required When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). IDE extension that lets you fix coding issues before they exist! The same problem we will have with "Add at least one assertion to this test case." How can we let this pass? 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. The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. Here is our source code: Sign in to download full-size image [4] To create a custom null validation method declare an attribute with name ValidatedNotNullAttribute and mark the parameter that is I suppose we can check that that is not null, but we cannot check that it is valid (in any portable way). 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. A reference to null should never be dereferenced/accessed. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to . 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. 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 . How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. Null pointer should not be dereferenced , If you call connect() function, it better do the connection, but failing simply because some ptr is NULL is not good behaviour -- failures should . 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 Pointer is so confusing : Stack with singly linked list in C - Stack To subscribe to this RSS feed, copy and paste this URL into your RSS reader. On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. Basically, yes. 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. very old code or C code being worked into c++ may have functions that expect the user to delete the data. 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. 1 Null pointers should not be dereferenced @CheckForNull String getName(){.} Why void pointer cannot be dereferenced? Explained by Sharing Culture This code also violates ERR33-C. Detect and handle standard library errors. sometimes FP occurs. Using Kolmogorov complexity to measure difficulty of problems? 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. 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. The null pointer check for writing or dereferencing should be a compiler flag or library setting. rev2023.3.3.43278. Is there a single-word adjective for "having exceptionally strong moral principles"? If you try to access any member variables or methods with that variable, you are trying to dereference it. Passing ownership of something also requires pointers. The method isNR(minRating) is a helper method that validate among other things, if the object minRating is null. I say "theoretical" because I have not successfully produced strings of this length in testing. We really appreciate your help. 4. There are many ways to resolve this. What is a NullPointerException, and how do I fix it?,What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? Which @NotNull Java annotation should I use? VB.NET static code analysis: Null pointers should not be dereferenced Does it just mean failing to correctly check if a value is null? What are the effects of exceptions on performance in Java? 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. This noncompliant code example is derived from a real-world example taken from a vulnerable version of the libpng library as deployed on a popular ARM-based cell phone [Jack 2007]. 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. Null - Null Pointer Exception In Java - GeeksforGeeks - A computer science 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. Thanks for contributing an answer to Stack Overflow! 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?) 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. All rights are expressly reserved. Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. 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. Doing so will at best cause abrupt program termination, without the Pointer members in structs are not checked. Handling Java NullPointerException and Best Practices - HowToDoInJava Dereferencing a null pointer is undefined behavior, typically abnormal program termination. 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. How to tell which packages are held back due to phased updates. Two null pointers will always be equal to each other. )}"); CWE - CWE-476: NULL Pointer Dereference (4.10) - Mitre Corporation Find centralized, trusted content and collaborate around the technologies you use most. If malloc() fails, it returns a null pointer that is assigned to c_str. 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). Is there a proper earth ground point in this switch box?