shekkbuilder

Meltdown fix impact on Redis performances in virtualized environments

Test performed with AOF enabled, fsync policy 1 second, allowing the rewrites to be triggered.

Command lines used:

./redis-benchmark -q -P 32 -n 1000000 -t set,get -r 1000000

shekkbuilder

#include <stdio.h>
//bsize=$(du -b ./data.dns|awk '{print $1}')
//hping3 -1 -p 53 -E ./data.dns -d ${bsize} 127.0.0.1 -jJ
main(  )
{
FILE *fp;

fp=fopen("data.dns", "w");
fprintf(fp, "%c%c%c%c", 0x00, 0x01, 0x01, 0x00);
fprintf(fp, "%c%c%c%c", 0x00, 0x01, 0x00, 0x00);

shekkbuilder

YARA Performance Guidelines

When creating your rules for YARA keep in mind the following guidelines in order to get the best performance from them. This guide is based on ideas and recommendations by Victor M. Alvarez and WXS.

• Revision 1.1, February 2016, applies to all YARA version 3.3+

Global Rules

Global rules are evaluated first. Only if they are satisfied non-global rules are evaluated. This may be useful if all samples exhibit the same characteristics. Use them combined with the "private" statement to suppress a match notification on the global rules.

shekkbuilder

obj-m += lkm_hello1.o
KDIR ?= /lib/modules/$(shell uname -r)/build

all:
	make -C $(KDIR) M=$(PWD) modules

clean:
	make -C $(KDIR) M=$(PWD) clean

shekkbuilder

Latency Comparison Numbers
--------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

shekkbuilder

#!/bin/bash

# install can-utils

git clone https://github.com/linux-can/can-utils.git
cd can-utils
./autogen.sh
./configure
make
sudo make install

shekkbuilder

#!/usr/bin/env python3
#
# Exploit for "assignment" of GoogleCTF 2017
#
# CTF-quality exploit...
#
# Slightly simplified and shortened explanation:
#
# The bug is a UAF of one or both values during add_assign() if a GC is
# triggered during allocate_value(). The exploit first abuses this two leak a

shekkbuilder

#!/usr/bin/env python3
#
# Exploit for "assignment" of GoogleCTF 2017
#
# CTF-quality exploit...
#
# Slightly simplified and shortened explanation:
#
# The bug is a UAF of one or both values during add_assign() if a GC is
# triggered during allocate_value(). The exploit first abuses this two leak a

shekkbuilder

#include <stdlib.h>
#include <stdio.h>
#include <sys/sysinfo.h>

void printMemStat(){
    struct sysinfo si;
    sysinfo(&si);
    printf("===\n");
    printf("Total: %llu\n", si.totalram);
    printf("Free: %llu\n", si.freeram);

shekkbuilder

import sys
def factors(n): return ([x]+factors(n/x) for x in xrange(2,n+1) if n%x==0).next() if n>1 else []
num=int(sys.argv[1])
print factors(num)