In the previous post we conquered compilation by constructing a small program that can be compiled without using libc. Understanding object code and the details...
In the previous post we conquered compilation by constructing a small program that can be compiled without using libc. Understanding object code and the details of an ELF executable are the next step in our adventure. We left off with the following program pieces: jesstess@kid-charlemagne:~$ cat stubstart.S .globl _start _start: call main movl $1, %eax xorl %ebx, %ebx int $0x80 jesstess@kid-charlemagne:~$ cat hello.c int main() { char *str = "Hello World"; return 0; }...
In the previous post we conquered compilation by constructing a small program that can be compiled without using libc. Understanding object code and the details of an ELF executable are the next step...
Here at Ksplice, we're always keeping a very close eye on vulnerabilities that are being announced in Linux. And in the last half of last year, it was very...
Here at Ksplice, we're always keeping a very close eye on vulnerabilities that are being announced in Linux. And in the last half of last year, it was very clear that NULL pointer dereference vulnerabilities were the current big thing. Brad Spengler made it abundantly clear to anyone who was paying the least bit attention that these vulnerabilities, far more than being mere denial of service attacks, were trivially exploitable privilege escalation vulnerabilities. Some...
Here at Ksplice, we're always keeping a very close eye on vulnerabilities that are being announced in Linux. And in the last half of last year, it was very clear that NULL pointer...
How much information is in a tweet? There are a lot of snarky answers to that. Let's talk mathematically, where information is measured in bits: How many bits...
How much information is in a tweet? There are a lot of snarky answers to that. Let's talk mathematically, where information is measured in bits: How many bits can be expressed in a tweet? It's kind of fun to try to figure out how to cram in the most information. Our current in-house record is 4.2 kilobits (525 bytes) per tweet, but this can definitely be bested. Twitter's 140-character limit has been under assault for some time, but nobody has decisively anointed a winner. To...
How much information is in a tweet? There are a lot of snarky answers to that. Let's talk mathematically, where information is measured in bits: How many bits can be expressed in a tweet? It's kind of...
As an exercise, I want to write a Hello World program in C simple enough that I can disassemble it and be able to explain all of the assembly to myself. This...
As an exercise, I want to write a Hello World program in C simple enough that I can disassemble it and be able to explain all of the assembly to myself. This should be easy, right? This adventure assumes compilation and execution on a Linux machine. Some familiarity with reading assembly is helpful. Here's our basic Hello World program: jesstess@kid-charlemagne:~/c$ cat hello.c #include <stdio.h> int main() {printf("Hello World\n");return 0; } Let's compile it and get a...
As an exercise, I want to write a Hello World program in C simple enough that I can disassemble it and be able to explain all of the assembly to myself. This should be easy, right? This...
Startup companies are always hunting for ways to accomplish as much as possible with what they have available. Last December we realized that we had a growing...
Startup companies are always hunting for ways to accomplish as much as possible with what they have available. Last December we realized that we had a growing queue of important engineering projects outside of our core technology that our team didn't have the time to finish anytime soon. To make matters worse, we wanted the projects completed right away, in time for our planned product launch in early February. So what did we do? The logical solution, of course. We...
Startup companies are always hunting for ways to accomplish as much as possible with what they have available. Last December we realized that we had a growing queue of important engineering projects...
Welcome to the Ksplice blog! I struggled for quite some time coming up with a grand opening for this blog. Something profound like "We the people, in order to...
Welcome to the Ksplice blog! I struggled for quite some time coming up with a grand opening for this blog. Something profound like "We the people, in order to form more perfect computing..." or "The history of the world is the history of rebooting". But that proved too hard, so instead, I want to take a moment to briefly tell the Ksplice story, in the hopes of providing a bit more insight into who we are and what we're all about. Ksplice was born on a beautiful summer day...
Welcome to the Ksplice blog! I struggled for quite some time coming up with a grand opening for this blog. Something profound like "We the people, in order to form more perfect computing..." or...
