To get a trial key
fill out the form below
Team License (a basic version)
Enterprise License (extended version)
* By clicking this button you agree to our Privacy Policy statement

Request our prices
New License
License Renewal
--Select currency--
* By clicking this button you agree to our Privacy Policy statement

Free PVS-Studio license for Microsoft MVP specialists
* By clicking this button you agree to our Privacy Policy statement

To get the licence for your open-source project, please fill out this form
* By clicking this button you agree to our Privacy Policy statement

I am interested to try it on the platforms:
* By clicking this button you agree to our Privacy Policy statement

Message submitted.

Your message has been sent. We will email you at

If you haven't received our response, please do the following:
check your Spam/Junk folder and click the "Not Spam" button for our message.
This way, you won't miss messages from our team in the future.

Buffer overflow

Buffer overflow

Mar 31 2013

Buffer overflow is an issue when a program is writing or reading data outside the buffer allocated in memory for this purpose. It usually occurs because of incorrect data and memory handling when the programming subsystem and operating system don't provide strict protection against this error. This type of errors is rather frequent and usually caused by misprints. There is also a related error - buffer underflow.

The Buffer Overflow and Buffer Underflow errors often cause uninitialized data to be used in the program and, as a consequence, its undefined behavior. Buffer overflow may also cause segmentation faults (Access Violation).

Since most high-level languages arrange program data in the process stack mixing them with control data, exploiting buffer overflows is one of the most popular hacking methods, as it allows an intruder to load and execute any machine code for the program and have the rights of the user account under which the program is running.

In such popular languages as C and C++ there is no integrated check of data reading/writing boundaries. This is a sacrifice for the efficient low-level memory handling. On the other hand, almost all the interpretive languages and JIT environments (Java RTE, .NET Framework) have an internal protection against buffer overflow.

To prevent using the buffer overflow vulnerability when executing a program there exist stack-smashing protection systems (Libsafe, StackGuard) and executable space protection systems. The difficulty of dynamic buffer overflow detection is determined by the fact that the program might work stably for a long time as long as uninitialized memory stores suitable values and the writable memory area is not used. Static analysis allows to find buffer overflow errors and related loopholes at the stage of code writing/debugging.

Here are several examples of this error detected in the code of real open-source projects with the PVS-Studio static analyzer.

The MAME project (game emulator). Buffer overflow.

#define CHD_SHA1_BYTES 20
#define CHD_V4_HEADER_SIZE 108

static chd_error header_read(...., chd_header *header)
  memcpy(header->parentsha1, &rawheader[100], CHD_SHA1_BYTES);

The 'rawheader' array consists of 108 bytes. The programmer intended to copy its contents starting with byte 100. The trouble is we will get outside the array boundaries: we're copying 20 bytes, while its only 8 bytes that can be copied.

Now consider an example of buffer underflow error. This is the Chromium project.

void Time::Explode(..., Exploded* exploded) const {
  ZeroMemory(exploded, sizeof(exploded));

The ZeroMemory function clears only a part of the Exploded structure. The reason is that the 'sizeof' operator returns the pointer size. We need to dereference the pointer to fix the error.

ZeroMemory(exploded, sizeof(*exploded));

Other samples of errors and vulnerabilities detected with the help of the static analysis methodology can be found here.


Popular related articles
The Last Line Effect

Date: May 31 2014

Author: Andrey Karpov

I have studied many errors caused by the use of the Copy-Paste method, and can assure you that programmers most often tend to make mistakes in the last fragment of a homogeneous code block. I have ne…
Free PVS-Studio for those who develops open source projects

Date: Dec 22 2018

Author: Andrey Karpov

On the New 2019 year's eve, a PVS-Studio team decided to make a nice gift for all contributors of open-source projects hosted on GitHub, GitLab or Bitbucket. They are given free usage of PVS-Studio s…
PVS-Studio ROI

Date: Jan 30 2019

Author: Andrey Karpov

Occasionally, we're asked a question, what monetary value the company will receive from using PVS-Studio. We decided to draw up a response in the form of an article and provide tables, which will sho…
The Ultimate Question of Programming, Refactoring, and Everything

Date: Apr 14 2016

Author: Andrey Karpov

Yes, you've guessed correctly - the answer is "42". In this article you will find 42 recommendations about coding in C++ that can help a programmer avoid a lot of errors, save time and effort. The au…
Characteristics of PVS-Studio Analyzer by the Example of EFL Core Libraries, 10-15% of False Positives

Date: Jul 31 2017

Author: Andrey Karpov

After I wrote quite a big article about the analysis of the Tizen OS code, I received a large number of questions concerning the percentage of false positives and the density of errors (how many erro…
The Evil within the Comparison Functions

Date: May 19 2017

Author: Andrey Karpov

Perhaps, readers remember my article titled "Last line effect". It describes a pattern I've once noticed: in most cases programmers make an error in the last line of similar text blocks. Now I want t…
PVS-Studio for Java

Date: Jan 17 2019

Author: Andrey Karpov

In the seventh version of the PVS-Studio static analyzer, we added support of the Java language. It's time for a brief story of how we've started making support of the Java language, how far we've co…
How PVS-Studio Proved to Be More Attentive Than Three and a Half Programmers

Date: Oct 22 2018

Author: Andrey Karpov

Just like other static analyzers, PVS-Studio often produces false positives. What you are about to read is a short story where I'll tell you how PVS-Studio proved, just one more time, to be more atte…
Appreciate Static Code Analysis!

Date: Oct 16 2017

Author: Andrey Karpov

I am really astonished by the capabilities of static code analysis even though I am one of the developers of PVS-Studio analyzer myself. The tool surprised me the other day as it turned out to be sma…
The way static analyzers fight against false positives, and why they do it

Date: Mar 20 2017

Author: Andrey Karpov

In my previous article I wrote that I don't like the approach of evaluating the efficiency of static analyzers with the help of synthetic tests. In that article, I give the example of a code fragment…

Comments (0)

Next comments
This website uses cookies and other technology to provide you a more personalized experience. By continuing the view of our web-pages you accept the terms of using these files. If you don't want your personal data to be processed, please, leave this site.
Learn More →