Wireless traffic is both interesting and delightfully accessible thanks to the broadcast nature of 802.11. I have spent many a lazy weekend afternoon watching...
Wireless traffic is both interesting and delightfully accessible thanks to the broadcast nature of 802.11. I have spent many a lazy weekend afternoon watching my laptop, the Tivo, and the router chatting away in a Wireshark window. As fun as the wireless traffic in one's house may be, there's something to be said for being able to observe a much larger ecosystem - one with more people with a more diverse set of operating systems, browsers, and intentions as they work on their...
Wireless traffic is both interesting and delightfully accessible thanks to the broadcast nature of 802.11. I have spent many a lazy weekend afternoon watching my laptop, the Tivo, and the...
There are many different kinds of bugs with many different causes. Sometimes, it's just some silly typo or type mismatch; other times, it's an algorithmic issue...
There are many different kinds of bugs with many different causes. Sometimes, it's just some silly typo or type mismatch; other times, it's an algorithmic issue or a correctness error; and occasionally, it appears to be something much stranger. This is a story about that last kind of bug, where finding the location of the problem is relatively straightforward, but figuring out how to fix it, or even why it's happening, isn't so easy. We first meet our hero, yours truly, as he...
There are many different kinds of bugs with many different causes. Sometimes, it's just some silly typo or type mismatch; other times, it's an algorithmic issue or a correctness error; and...
If you're a veteran system administrator, you might remember an era of extremely expensive hard disk storage, when any serious network would have a beefy...
If you're a veteran system administrator, you might remember an era of extremely expensive hard disk storage, when any serious network would have a beefy central file server (probably accessed using the Network File System, NFS) that formed the lifeblood of its operations. It was a well-loved feature as early as Linux kernel 2.0 that you could actually boot your machine with a root filesystem in NFS and have no local disk at all. Hardware costs went down, similar machines...
If you're a veteran system administrator, you might remember an era of extremely expensive hard disk storage, when any serious network would have a beefy central file server (probably accessed using...
~jesstess
How much information is in a tweet? A month ago, we asked that question, in the First International Longest Tweet Contest. The most longwinded tweeters on earth...
How much information is in a tweet? A month ago, we asked that question, in the First International Longest Tweet Contest. The most longwinded tweeters on earth answered the call. The result: about 4,370 bits. Congrats to the entrants, and best of luck honing your entries for next year! Ksplice is pleased to award our acclaimed, limited-edition T-shirts to the top three contenders. In no particular order, they are: Todd Lehman Mr. Lehman's entry, originally posted as a blog...
How much information is in a tweet? A month ago, we asked that question, in the First International Longest Tweet Contest. The most longwinded tweeters on earth answered the call. The result: about...
Last time, we took a brief look at virtual memory and what a NULL pointer really means, as well as how we can use the mmap(2) function to map the NULL page so...
Last time, we took a brief look at virtual memory and what a NULL pointer really means, as well as how we can use the mmap(2) function to map the NULL page so that we can safely use a NULL pointer. We think that it's important for developers and system administrators to be more knowledgeable about the attacks that black hats regularly use to take control of systems, and so, today, we're going to start from where we left off and go all the way to a working exploit for a NULL...
Last time, we took a brief look at virtual memory and what a NULL pointer really means, as well as how we can use the mmap(2) function to map the NULL page so that we can safely use a NULL pointer. We...
Reminder: The entry period for the 1st International Longest Tweet Contest closes today. Good luck! ~keithw
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...
