thesis: Add headings and first subsection

doc/README.md

@@ -16,7 +16,7 @@ From the [ENVIRONMENT section in the Linux manual page ld.so(8)](https://www.man
 * No need to re-link
 * Works for *all* functions
 * Works only on dynamically linked executables
-* Intercepts all calls (including stack allocations etc.)
+* Intercepts all calls (including calls inside libraries etc.)
 
 Example (`preload.c`):
 ```c

thesis/.gitignore

@@ -18,3 +18,4 @@
 *.toc
 *.xmpdata
 *.xmpi
+*.bbl

thesis/Makefile

@@ -3,11 +3,10 @@
 all: thesis.pdf clean-out
 
 %.pdf: %.tex $(wildcard src/*)
-	pdflatex $<
-	pdflatex $<
+	latexmk -pdf $<
 
-clean: clean-out
-	rm -rf *.pdf
+clean:
+	latexmk -C
 
 clean-out:
-	rm -rf *.acn *.aux *.glo *.glsdefs *.idx *.ist *.loa *.lof *.log *.lot *.mw *.out *.toc *.xmpdata *.xmpi
+	latexmk -c

thesis/src/01.introduction.tex

@@ -3,6 +3,18 @@
 
 Lorem Ipsum.
 
-\section{Something}
+\section{TODO: Why intercept?}
+
+Lorem Ipsum.
+
+\section{TODO: Why are current solutions not enough?}
+
+Lorem Ipsum.
+
+\section{TODO: Linux/C/ELF call structure}
+
+Lorem Ipsum.
+
+\section{TODO: System Calls vs. Function Calls}\label{sec:system-calls-vs-function-calls}
 
 Lorem Ipsum.

thesis/src/02.intercept.tex

@@ -2,3 +2,150 @@
 \chapter{Intercepting Function Calls}\label{ch:intercepting-function-calls}
 
 Lorem Ipsum.
+
+\section{Identified Methods for Intercepting Function and System Calls}\label{sec:methods-for-intercepting}
+
+Lorem Ipsum.
+
+\subsection{Preloading using \texttt{LD\_PRELOAD}}\label{subsec:preloading}
+
+To execute binary files on Linux systems, a dynamic linker is needed at runtime.
+(Unless the binaries were statically linked at compile-time.)
+Usually, \texttt{ld.so} and \texttt{ld-linux.so} are used as dynamic linkers.
+They find and load the shared objects (shared libraries) needed by a program, prepare the program and finally run it.
+\cite{ld.so.8}
+
+As the overwhelming majority of programs are dynamically linked,
+most function calls to other libraries (like to the C standard library) reference a shared object, which has to be loaded by the linker at runtime.
+Therefore, it would be possible to ``hijack'' (or intercept) these function calls,
+when the linker would allow loading other functions instead of the proper ones.
+
+Luckily, \texttt{ld.so} allows this so-called ``preloading''.
+See the ENVIRONMENT section in the ld.so(8) Linux manual page~\cite{ld.so.8}:
+
+\begin{quote}
+  \begin{description}
+    \item[\texttt{LD\_PRELOAD}]
+    A list of additional, user-specified, ELF shared objects to be loaded before all others.
+    This feature can be used to selectively override functions in other shared objects.
+    \lbrack\dots\rbrack
+  \end{description}
+\end{quote}
+
+This means, by setting the environment variable \texttt{LD\_PRELOAD}, it is possible to override specific functions.
+The listings \ref{lst:preload.c} and \ref{lst:preload} try to illustrate this.
+
+\begin{listing}[htbp]
+  \begin{minted}[linenos]{c}
+#include <stdlib.h>
+#include <dlfcn.h>
+#include <errno.h>
+
+void *malloc(size_t size) {
+    // before call to malloc
+    void *(*_malloc)(size_t);
+    if ((_malloc = dlsym(RTLD_NEXT, "malloc")) == NULL) {
+        errno = ENOSYS;
+        return NULL;
+    }
+    void *ret = _malloc(size);
+    // after call to malloc
+    return ret;
+}
+  \end{minted}
+  \caption{Contents of \texttt{preload.c}.}
+  \label{lst:preload.c}
+\end{listing}
+
+\begin{listing}[htbp]
+  \begin{minted}{shell}
+# ./main is already compiled and ready
+gcc -shared -fPIC -o preload.so preload.c
+LD_PRELOAD="$(pwd)/preload.so" ./main
+  \end{minted}
+  \caption{Compile \texttt{preload.so} and run a program with \texttt{LD\_PRELOAD}.}
+  \label{lst:preload}
+\end{listing}
+
+The function \texttt{dlsym} is used to retrieve the original address of the \texttt{malloc} function.
+\texttt{RTLD\_NEXT} indicates to find the next occurrence of \texttt{malloc} in the search order after the current object.
+\cite{dlsym.3}
+
+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.
+
+\subsection{Wrapper Functions in \texttt{gcc}}\label{subsec:wrapper-functions}
+
+From the OPTIONS section in the ld(1) Linux manual page~\cite{ld.1}:
+
+\begin{quote}
+  \begin{description}
+    \item[\texttt{--wrap=\textit{symbol}}]
+      Use a wrapper function for \texttt{\textit{symbol}}.
+      Any undefined reference to \texttt{\textit{symbol}} will be resolved to \texttt{\_\_wrap\_\textit{symbol}}.
+      Any undefined reference to \texttt{\_\_real\_\textit{symbol}} will be resolved to \texttt{\textit{symbol}}.
+
+      This can be used to provide a wrapper for a system function.
+      The wrapper function should be called \texttt{\_\_wrap\_\textit{symbol}}.
+      If it wishes to call the system function, it should call \texttt{\_\_real\_\textit{symbol}}.
+      \lbrack\dots\rbrack
+  \end{description}
+\end{quote}
+
+From the OPTIONS section in the gcc(1) Linux manual page~\cite{gcc.1}:
+
+\begin{quote}
+  \begin{description}
+    \item[\texttt{-Wl,\textit{option}}]
+      Pass \texttt{\textit{option}} as an option to the linker.
+      If \texttt{\textit{option}} contains commas, it is split into multiple options at the commas.
+      You can use this syntax to pass an argument to the option.
+      For example, \texttt{-Wl,-Map,output.map} passes \texttt{-Map output.map} to the linker.
+      When using the GNU linker, you can also get the same effect with \texttt{-Wl,-Map=output.map}.
+      \lbrack\dots\rbrack
+  \end{description}
+\end{quote}
+
+\subsection{Kernel Module}\label{subsec:kernel-module}
+
+Lorem Ipsum.
+
+\subsection{Emulation}\label{subsec:emulation}
+
+Lorem Ipsum.
+
+\subsection{Modifying the Kernel}\label{subsec:modifiying-kernel}
+
+Lorem Ipsum.
+
+\subsection{Conclusion}\label{subsec:conclusion}
+
+Lorem Ipsum.
+
+\section{Combining Preloading and Wrapper Functions}\label{sec:combining-preloading-and-wrapper-functions}
+
+Lorem Ipsum.
+
+\section{Retrieving Function Argument Values}\label{sec:Retrieving-function-argument-values}
+
+Lorem Ipsum.
+
+\section{Determining Function Call Location}\label{sec:determining-function-call-location}
+
+Lorem Ipsum.
+
+\section{Example}\label{sec:intercepting-example}
+
+Lorem Ipsum.
+
+\section{Analyzing Intercepted Function Calls}\label{sec:analyzing-intercepted-function-calls}
+
+Lorem Ipsum.
+
+\section{Parsing Intercepted Function Calls in Python}\label{sec:parsing-intercepted-function-calls}
+
+Lorem Ipsum.
+
+\section{Automated Testing on Intercepted Function Calls}\label{sec:automated-testing-on-intercepted-function-calls}
+
+Lorem Ipsum.

thesis/src/03.manipulate.tex

@@ -2,3 +2,21 @@
 \chapter{Manipulating Function Calls}\label{ch:manipulating-function-calls}
 
 Lorem Ipsum.
+
+Unix-Sockets, TCP-Sockets, \dots
+
+\section{Defining a Protocol}\label{sec:defining-a-protocol}
+
+Lorem Ipsum.
+
+\section{Parsing Responses}\label{sec:parsing-responses}
+
+Lorem Ipsum.
+
+\section{Creating a Socket Server in Python}\label{sec:creating-a-socket-server-in-python}
+
+Lorem Ipsum.
+
+\section{Automated Testing using Function Call Manipulation}\label{sec:automated-testing-using-function-call-manipulation}
+
+Lorem Ipsum.

thesis/src/04.related-work.tex

@@ -2,3 +2,7 @@
 \chapter{Related Work}\label{ch:related-work}
 
 Lorem Ipsum.
+
+What other solutions are available?
+What are the differences?
+What are the characteristics?

thesis/src/05.conclusion.tex

@@ -2,3 +2,5 @@
 \chapter{Conclusion}\label{ch:conclusion}
 
 Lorem Ipsum.
+
+Perhaps do some study/``research'' on performance (CPU/memory/\dots).

thesis/src/99.intercept.bib

@@ -0,0 +1,12 @@
+@manual{ld.so.8,
+    title = {ld.so(8) -- System Manager's Manual -- Linux manual pages},
+}
+@manual{dlsym.3,
+    title = {dlsym(3) -- Library Functions Manual -- Linux manual pages},
+}
+@manual{ld.1,
+    title = {ld(1) -- GNU Development Tools -- Linux manual pages},
+}
+@manual{gcc.1,
+    title = {GCC(1) -- GNU -- Linux manual pages},
+}

thesis/thesis.tex

@@ -37,6 +37,9 @@
 \usepackage{morewrites} % Increases the number of external files that can be used.
 \usepackage[a-2b,mathxmp]{pdfx}      % Enables PDF/A compliance. Loads the package hyperref and has to be included second to last.
 \usepackage[acronym,toc]{glossaries} % Enables the generation of glossaries and lists of acronyms. This package has to be included last.
+\usepackage{minted}
+\usepackage{chngcntr}
+\counterwithin{listing}{chapter}
 
 % Set PDF document properties
 \hypersetup{
@@ -167,7 +170,7 @@
 \printglossaries
 
 % Add a bibliography.
-\bibliographystyle{alpha}
+\bibliographystyle{plain}
 \bibliography{src/99.intercept}
 
 \end{document}