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thesis: Apply proofreading suggestions

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Lorenz Stechauner
2025-08-19 12:35:54 +02:00
parent 30121e4543
commit 8712bdc461
7 changed files with 32 additions and 33 deletions
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thesis/src/02.intercept.tex
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@@ -56,8 +56,7 @@ exit_group(0) = ?
\label{lst:strace}
\end{listing}
This approach works great for debugging and other use-cases,
but only intercepting system calls does not statisfy the requirements for this work.
This approach works well for debugging and other use cases, but intercepting system calls alone does not satisfy the requirements of this work.
\subsection{\texttt{ltrace} Command}\label{subsec:ltrace}
@@ -210,7 +209,7 @@ The function \texttt{dlsym} is used to retrieve the original address of the \tex
\cite{dlsym.3}
By using this method, it is possible to override, and therefore wrap, any function as long as the targeted binary was not statically linked.
Although, one has to be aware that not only function calls inside the targeted binary, but also calls inside other libraries (e.g., to \texttt{malloc}) are redirected to the overriding function.
However, one must be aware that not only function calls inside the targeted binary, but also calls inside other libraries (e.g., \texttt{malloc}) are redirected to the overriding function.
\subsection{Conclusion}\label{subsec:methods-for-intercepting-conclusion}
@@ -260,7 +259,7 @@ It should always be possible to fully parse the recorded calls without any speci
\subsection{Numbers}\label{subsec:retrieving-numbers}
The most simple types of argument are plain numbers, like integers (\texttt{int}, \texttt{long}, \ldots) or floating point numbers (\texttt{float}, \texttt{double}).
The simplest types of arguments are plain numbers, like integers (\texttt{int}, \texttt{long}, \ldots) or floating point numbers (\texttt{float}, \texttt{double}).
(In fact, \textit{all} arguments are represented as numbers or integers.
See the following subsections for examples.)
Plain numbers may be formatted simply as what they are, in base 10 notation, or with a prefix like \texttt{0x} for hexadecimal or \texttt{0} for octal representation.
@@ -284,7 +283,7 @@ Special values inside the string are escaped with a backslash.
Example: \texttt{sem\_unlink(0x1234:"/test-semaphore")}.
Another type of ``string'' in C is a buffer with a known length.
Another type of string-like data in C is a buffer with a known length.
When buffers are used, usually another argument is passed to the function which indicates the length of the buffer.
This fact may be used to print out the contents of the buffer in the same way as normal C strings.
@@ -338,8 +337,8 @@ Example (\texttt{malloc}): \\
\texttt{return 0x1234; errno 0}, \\
\texttt{return -1; errno ENOMEM}.
Some libc functions return their results via a pointer which was previously given to them as an argument.
The \texttt{pipe} function is called with an \texttt{int} array of size two as argument and stores its two pipe ends into this array.
Some libc functions return their results via a pointer, which was previously given to them as an argument.
The \texttt{pipe} function is called with an \texttt{int} array of size two as an argument and stores its two pipe ends into this array.
The \texttt{read} function is called with a pointer to a buffer and a corresponding size and stores its read data into this buffer.
Example (\texttt{pipe}): \\
@@ -548,7 +547,7 @@ This includes the offset relative to the calling binary and a source file and li
\begin{listing}[htbp]
\inputminted[fontsize=\tiny]{text}{src/listings/intercept-client.txt}
\caption{Recoreded function calls from \texttt{./client}.}
\caption{Recorded function calls from \texttt{./client}.}
\label{lst:intercept-client}
\end{listing}
@@ -565,7 +564,7 @@ The \texttt{free} function, on the other hand, has the pre-condition that the pa
Any violation of such pre- and post-conditions may be reported as non-compliant behavior.
\cite{malloc.3}
This means that intercepted function calls allow a tester to check if programmers use library function in compliance to their specification.
This means that intercepted function calls allow a tester to check whether programmers use library functions in compliance with their specifications.
Other checks may also include guards to calls to ``forbidden'' functions, or that specific functions must be called exactly three times.
Another important post-condition of most library functions is the return value, which in most cases indicates success or failure of an operation.
However, intercepting of calls alone may not be able to verify if a program really checks the return value of a function and acts accordingly.
@@ -597,7 +596,7 @@ By only intercepting these functions, it is possible to check if all allocated m
\subsection{Validating Resource Management}\label{subsec:validating-resource-management}
Besides memory management, the proper use of other resources, most notably file descriptors, may be checked.
In addition to memory management, the proper use of other resources---most notably file descriptors---can also be checked.
Many functions in the C standard library rely on file descriptors.
It may be checked if file descriptors were properly acquired, if only previously acquired file descriptors are used, and if these file descriptors are closed after their use.
Relevant for this work are also semaphores because they do not rely on file descriptor in their API\@.