208 data (Lines 2 to 9). Since there is no real computation going

   208 data (Lines 2 to 9). Since there is no real computation going

   209 on inside \pcode{foo}, the function then just restores the

   209 on inside \pcode{foo}, the function then just restores the

   210 stack to its old state and crucially sets the return address

   210 stack to its old state and crucially sets the return address

   211 where the computation should resume (Line 9 in the code on the

   211 where the computation should resume (Line 9 in the code on the

   212 left-hand side). The instruction \code{ret} then transfers

   212 left-hand side). The instruction \code{ret} then transfers

   214 instruction just after the call to \pcode{foo}, that is Line

   214 instruction just after the call to \pcode{foo}, that is Line

   215 9.

   215 9.

   216  

   216  

   217 Another part of the ``conspiracy'' of buffer overflow attacks

   217 Another part of the ``conspiracy'' of buffer overflow attacks

   218 is that library functions in C look typically as follows:

   218 is that library functions in C look typically as follows:

   684 compiler to include debugging information and also produce

   684 compiler to include debugging information and also produce

   685 non-optimised code (the latter makes the output of the code a

   685 non-optimised code (the latter makes the output of the code a

   686 bit more predictable). The third is important as it switches

   686 bit more predictable). The third is important as it switches

   687 off defences like the stack canaries. The fourth again makes it

   687 off defences like the stack canaries. The fourth again makes it

   688 a bit easier to read the code. The final option makes the

   688 a bit easier to read the code. The final option makes the

   690 works as intended. While this might be considered

   690 works as intended. While this might be considered

   691 cheating....since I explicitly switched off all defences, I

   691 cheating....since I explicitly switched off all defences, I

   692 hope I was able convey that this is actually not too far from

   692 hope I was able convey that this is actually not too far from

   693 realistic scenarios. I have shown you the classic version of

   693 realistic scenarios. I have shown you the classic version of

   694 the buffer overflow attacks. Updated variants do exist. Also

   694 the buffer overflow attacks. Updated variants do exist. Also