Home » Blog » Tags » bugs

bugs

Zero, one, two, Freddy's coming for you

By Andrey Karpov | Feb 14, 2020 05:22 AM | Tags: typos quality copy-paste code review bugs

The article might be of interest for authors of books, articles, and C++ coding standards. Based on the given material, you can discuss questions of C++ code quality and ways how to reduce the likelihood of errors' occurence.

Zero, one, two, Freddy's coming for you

by Andrey Karpov

From the article:

This post continues the series of articles, which can well be called «horrors for developers». This time it will also touch upon a typical pattern of typos related to the usage of numbers 0, 1, 2. The language you're writing in doesn't really matter: it can be C, C++, C#, or Java. If you're using constants 0, 1, 2 or variables' names contain these numbers, most likely, Freddie will come to visit you at night. Go on, read and don't say we didn't warn you.

 

Top 10 Bugs Found in C++ Projects in 2019

By Andrey Karpov | Dec 19, 2019 07:47 AM | Tags: pvs-studio open source bugs

Another year is drawing to an end, and it's a perfect time to make yourself a cup of coffee and reread the reviews of bugs collected across open-source projects over this year.

Top 10 Bugs Found in C++ Projects in 2019

by Maxim Zvyagintsev

From the article:

float yScale = 1.0 / tan((3.141592538 / 180.0) * fov / 2);

There's a tiny typo in the Pi number (3,141592653...): the number "6" is missing at the 7th decimal place.
 

Macro Evil in C++ Code

By Andrey Karpov | Mar 20, 2019 10:53 AM | Tags: macros bugs

The C++ language opens extensive opportunities to go without macros. So let’s try to use macros as seldom as possible!

Macro Evil in C++ Code

by Andrey Karpov

From the article:

The ATL library provides such macros, as A2W, T2W and so on for string conversion. However, few people know that it is very dangerous to use these macros inside loops. Within the macro, a call to the alloca function occurs, which will repeatedly allocate memory on each loop iteration on the stack. A program makes show that it works correctly. Once a program starts to handle longer strings and the number of loop iterations increases, the stack can just end at the most unexpected moment.

Technologies used in the PVS-Studio code analyzer for finding bugs and potential vulnerabilities

By Andrey Karpov | Nov 21, 2018 02:00 AM | Tags: static code analysis pvs-studio c++ bugs

The PVS-Studio analyzer is gradually becoming more complicated but these changes can be hardly described in a Release-history. For example, this year we have consistently implemented symbolic computations in the analyzer. This is why it was agreed to write a note on algorithms and technologies, which PVS-Studio now uses to search for errors and potential vulnerabilities.

Technologies used in the PVS-Studio code analyzer for finding bugs and potential vulnerabilities

by Andrey Karpov

From the article:

Here a mixture of technologies is working: data flow analysis, symbolic execution, and automatic method annotation (we will cover this technology in the next section). The analyzer sees that X variable is used in the Div function as a divisor. On this basis, a special annotation is built for the Div function. Further it is taken into account that in the function a range of values [0..4] is passed as the X argument. The analyzer comes to a conclusion that a division by 0 has to occur.

PVS-Studio is now available on macOS: 64 weaknesses in the Apple's XNU Kernel

By Andrey Karpov | Mar 28, 2018 05:16 AM | Tags: xnu kernel static code analysis pvs-studio macos bugs

A new version of the PVS-Studio analyzer 6.23 is working under macOS, which allows you to check the projects written in C and C++. Our team decided to perform a XNU Kernel check to coincide it with this event.

PVS-Studio is now available on macOS: 64 weaknesses in the Apple's XNU Kernel

by Andrey Karpov

From the article:

Although the XNU Kernel is relatively small, it's a challenge to study the analyzer warnings alone, which takes much time. False positives make the check more complicated, since I haven't performed the preliminary analyzer configuration. I just quickly looked through the warnings, writing out code fragments that, in my opinion, represent interest. This is more than enough for writing a quite large article. PVS-Studio analyzer easily finds a large number of interesting bugs.

PVS-Studio: searching software weaknesses

By Andrey Karpov | Mar 16, 2017 06:44 AM | Tags: vulnerabilities security pvs-studio cwe common weakness enumeration bugs

As we check Apache HTTP Server, we see bugs crawling everywhere across the code. But wait! These are not just bugs, but security weaknesses!

PVS-Studio: searching software weaknesses

by Andrey Karpov, Phillip Khandeliants

From the article:

PVS-Studio has always been able to detect a large number of various security defects (potential vulnerabilities) in the program code. However, historically, we positioned PVS-Studio as a tool to search for errors. We see a trend in the software development to look for vulnerabilities in the code, although it is just the same. It seems to us that it is high time to do the rebranding of our static analyzer PVS-Studio. We will start with Common Weakness Enumeration (CWE). This article provides a table that shows matches of PVS-Studio diagnostic warnings of with the classifier. The table will be gradually updated and changed, but we can already use the table to write articles about security defects detected in projects. We suppose it would attract more attention of the software security specialists.

Finding bugs in the code of LLVM project with the help of PVS-Studio

By Andrey Karpov | Oct 31, 2016 09:57 AM | Tags: pvs-studio open source llvm clang bugs

Let's take a look at the suspicious fragments in the LLVM code which PVS-Studio detected.

Finding bugs in the code of LLVM project with the help of PVS-Studio

by Andrey Karpov

From the article:

LLVM developers, of course, will be able to understand if there is a bug here or not. I have to play detective. Looking at the code, I was thinking in the following direction: The function should read the opening bracket '<', then it reads the identifiers and commas in the loop. If there is no comma, we expected a closing bracket. If something goes wrong, then the function returns an error code. I reckon there was supposed to be the following algorithm of the function work (pseudocode).

PVS-Studio C/C++ static code analyzer for Linux

By Andrey Karpov | Oct 26, 2016 04:54 AM | Tags: static code analysis pvs-studio linux bugs

We released the first version of PVS-Studio analyzer for Linux. Now Linux developers are getting a new powerful tool to fight bugs in the code.

PVS-Studio for Linux

From the news:

Starting with the 6.10 version, PVS-Studio analyzer supports not only Windows, but the Linux too.

PVS-Studio performs static code analysis and generates a report that helps a programmer find and fix bugs. PVS-Studio performs a wide range of code checks, it is also useful to search for misprints and Copy-Paste errors. Demonstrative examples of such errors: V501, V517, V522, V523, V571, V611.

The new Linux version (.deb, .rpm, .tgz) is available for download on the page: http://www.viva64.com/en/pvs-studio-download-linux/

Bugs found in GCC with the help of PVS-Studio

By Andrey Karpov | Sep 1, 2016 02:01 AM | Tags: static code analysis pvs-studio gcc bugs basics

I regularly check various open-source projects to demonstrate the abilities of the PVS-Studio static code analyzer (C, C++, C#). Now it is time for the GCC compiler to get checked.

Bugs found in GCC with the help of PVS-Studio

by Andrey Karpov

From the article:

This part could also be called "Example number one thousand, why macros are bad". I really don't like macros and always urge people to avoid using them if possible. Macros make it difficult to read the code, provoke errors, and make the work of static analyzers harder. As best I can tell, from a brief interaction with the GCC code, the authors are big fans of macros. I was really tired looking at what the macros are expanded to, and perhaps missed quite a number of interesting errors. I should confess that I was lazy at times. But still, I will demonstrate a couple of errors, connected with macros.