Journey of Life

January 30, 2015

5Ghz WiFi Channels (US)

Source: http://www.revolutionwifi.net/blog/?month=april-2014&view=calendar

convert pdf to png gray

gs -sDEVICE=pnggray -sOutputFile=page-%03d.png -r600x600 -f test-ecg.pdf

January 27, 2015

Turn your PHP project to a standalone Windows application

Free and Open source ones:

1. PHP Desktop (I tried it and it works really well)
https://code.google.com/p/phpdesktop/

2. http://sourceforge.net/projects/wapache/

3. https://github.com/naetech/nightrain

Paid ones:
http://www.zzee.com/phpexe/

December 18, 2014

Install a minimal X on Linux

apt-get install xinit i3 rxvt

i3 is the lightweight window manager
rxvt is the terminal
xinit gives you X windows and the famous "startx" command

To make i3 use your full screen resolution, create the file ~/.xinitrc and put the following there

xrandr --output Virtual1 --mode 1680x1050
exec i3

You may need to change the name "Virtual1" to something else. Use xrandr to list all the known windows (you first need to have X windows running though)

December 12, 2014

Home Depot Protection Plan Phone number: 1-888-543-4757

December 9, 2014

p11tool, gnutls and PIV CAC card

p11tool --list-all-certs

p11tool --login --export "pkcs11:model=PKCS%2315%20emulated;manufacturer=piv_II;serial=36889385781093f6;token=PIV_II%20%28PIV%20Card%20Holder%20pin%29;id=%02;object=Certificate%20for%20Digital%20Signature;object-type=cert" > /tmp/02.cert

p11tool --list-all-privkeys --login

x509 certificate subject name and OID

In a X509 certificate, there is always a subject name like the following:

$ openssl x509 -in user-cert.pem -text -noout
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 1373122324 (0x51d82f14)
Signature Algorithm: sha256WithRSAEncryption
Issuer: CN=CA
Validity
Not Before: Jul 6 14:52:05 2013 GMT
Not After : May 15 14:52:05 2023 GMT
Subject: UID=test,CN=A user

Inside the subject line, there can be multiple subparts, such as CN=xxx, DC=xxxx, UID=xxx, OU=xxx, C=xxx, ... Each subpart is represented in the certificate as an OID that is globally unique and registred with IETF. For example, the OID of CN is 2.5.4.3, and the OID of UID is 0.9.2342.19200300.100.1.1. How are we supposed to find out the OID? Openssl provides a command option for just.

openssl x509 -in user-cert.pem -text -noout -nameopt RFC2253,oid

This command will print out the cert with the OID=xxx instead of CN=xxx.

December 8, 2014

cross compile openconnect

Openconnect is a nice open source SSL VPN client for Cisco AnyConnect, and also for the open source SSL vpn server ocserv (hosted on the same website as openconnect). Below are some tips on how to cross compile openconnect for ARM, with GnuTLS

Openconnect works with both Openssl and GnuTLS. However, to use hardware token (smart card, etc), you will need GnuTLS.

Dependencies:

Openconnect depends on GnuTLS (3.3.9)
GnuTLS depends on libnettle, and libhogweed 2.7.1 (both in the nettle package)
libnettle depends on gnu GMP (libgmp, version 6.0.0)

To use hardware token, GnuTLS also depends on p11-kit (version 0.22.1) and pcsc-lite (version 1.8.11), and opensc (0.14.0), which depends on pcsc-lite.

All of these packages support autoconfig so that one can run "configure" to generate the makefile(s). We use the --prefix "/opt/ncs-install" to install all packages. Below are the customized "configure" scripts for each package:

p11-kit-0.22.1:
CC=arm-none-linux-gnueabi-gcc CXX=arm-none-linux-gnueabi-g++ ./configure --host=arm-linux --prefix=/opt/ncs-install \
--without-libffi --without-libtasn1

gmp-6.0.0:
CC=arm-none-linux-gnueabi-gcc CXX=arm-none-linux-gnueabi-g++ ./configure --host=arm-linux --prefix=/opt/ncs-install

nettle-2.7.1:

CFLAGS=-I/opt/ncs-install/include LDFLAGS=-L/opt/ncs-install/lib CC=arm-none-linux-gnueabi-gcc CXX=arm-none-linux-gnueabi-g++ ./configure --host=arm-linux --prefix=/opt/ncs-install

pcsc-lite-1.8.11:

CFLAGS="-I/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/include/"

CC=arm-none-linux-gnueabi-gcc ./configure -host=arm-linux --disable-libudev --enable-libusb \

LIBUSB_CFLAGS="-I/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/include/libusb-1.0/ -L/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/lib" \

LIBUSB_LIBS="-lusb-1.0"

/opensc-0.14.0:

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

export LTLIB_LIBS="-L/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/lib/ -lltdl"

export PCSC_CFLAGS="-I$DIR/../pcsc-lite-1.8.11/src/PCSC"

export LIBTOOL_SYSROOT_PATH=/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/

export CFLAGS="-I/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/include -L/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/lib"

export LDFLAGS="-lcrypto"

export CC=arm-none-linux-gnueabi-gcc

./configure -host=arm-linux -v

gnutls-3.3.9:

CFLAGS=-I/opt/ncs-install/include LDFLAGS=-L/opt/ncs-install/lib \

ZLIB_CFLAGS=-I/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/include/ \

ZLIB_LIBS="-L/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/lib -lz" \

CC=arm-none-linux-gnueabi-gcc CXX=arm-none-linux-gnueabi-g++ ./configure --host=arm-linux --prefix=/opt/ncs-install \

--with-nettle-mini --disable-crywrap \

--with-p11-kit \

--with-default-trust-store-file=/etc/ssl/certs/ca-certificates.crt

openconnect-7.00:

LIBPCSCLITE_CFLAGS=-I/opt/ncs-install/include/PCSC/ \

LIBPCSCLITE_LIBS="-L/opt/ncs-install/lib -lpcsclite" \

LIBXML2_CFLAGS=-I/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/include/libxml2/ \

LIBXML2_LIBS="-L/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/lib -lxml2" \

CFLAGS=-I/opt/ncs-install/include LDFLAGS=-L/opt/ncs-install/lib \

LDFLAGS="-L/opt/ncs-install/lib -lp11-kit -lnettle -lhogweed -lgmp" \

ZLIB_CFLAGS=-I/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/include/ \

ZLIB_LIBS="-L/opt/ezsdk/linux-devkit/arm-none-linux-gnueabi/usr/lib -lz" \

CC=arm-none-linux-gnueabi-gcc ./configure --prefix=/opt/install --disable-nls --host=arm-linux --without-openssl --with-gnutls

December 4, 2014

how to verify certificate signed by intermediate CA

openssl verify -untrusted intermediate-ca.pem your-cert.pem

Put the list of intermediate CA (in PEM format, concatenated ) in intermediate-ca.pem, and use the "-untrusted" option. That name tricked me initially, and that's the one to use.

The above command is to use the system CA list to verify the cert. If you have your own CA, just use the option "-CAfile your-ca.pem".

November 25, 2014

How to make IE not cache your golang web app responses

var w http.ResponseWriter
w.Header().Set("cache-control", "priviate, max-age=0, no-cache")
w.Header().Set("pragma", "no-cache")
w.Header().Set("expires", "-1")

November 24, 2014

Clear windows event log

Run this following line in PowerShell as Admin:

wevtutil el | Foreach-Object {Write-Host "Clearing $_"; wevtutil cl "$_"}

November 19, 2014

Read godoc in vim using Shift K

Add the following to your ~/.vim/ftplugin/go.vim (the key here is to use <cfile> not <cword>)

fun! ReadMan()
" Assign current file under cursor to a script variable:
let s:man_word = expand('<cfile>')
:exe ":Godoc " . s:man_word
endfun
" Map the K key to the ReadMan function:
map K :call ReadMan()<CR>

=======UPDATE========
Had a better way for this:

1. Create a file in your ~/bin called godoc.sh with the following content:
#!/bin/sh
fullpkg=`gawk -v "cmd=$1" '
{ FS="/" }
{
if ($NF==cmd || $0 ==cmd){
printf("%s",$0);
exit;
}
}' ~/bin/gopkg-list.txt`
echo -n $fullpkg

2. Create a text file in ~/bin/gopkg-list.txt with the following contents:

log/syslog

unicode/utf8

unicode/utf16

testing

hash/crc64

hash/adler32

hash/fnv

hash/crc32

archive/zip

archive/tar

expvar

mime

reflect

crypto/des

crypto/sha1

crypto/subtle

crypto/aes

crypto/md5

crypto/cipher

crypto/rand

crypto/ecdsa

crypto/tls

crypto/sha512

crypto/x509

crypto/sha256

crypto/elliptic

crypto/hmac

crypto/rsa

crypto/x509/pkix

crypto/rc4

crypto/dsa

flag

strings

sync

os/user

os/signal

os/exec

fmt

syscall

time

runtime/pprof

runtime/cgo

runtime/debug

runtime/race

net/http/httputil

net/http/cookiejar

net/http/fcgi

net/http/pprof

net/http/cgi

net/http/httptest

net/rpc/jsonrpc

net/mail

net/http

net/textproto

net/url

net/rpc

net/smtp

io/ioutil

math

database/sql/driver

database/sql

mime/multipart

bytes

errors

sort

bufio

encoding

log

path/filepath

index/suffixarray

net

crypto

sync/atomic

go/printer

go/doc

go/scanner

go/ast

go/parser

go/token

go/build

go/format

unicode

image

runtime

html/template

regexp

html

container/ring

container/list

container/heap

hash

path

regexp/syntax

text/template/parse

text/tabwriter

text/template

text/scanner

strconv

testing/quick

testing/iotest

compress/flate

compress/zlib

compress/lzw

compress/bzip2

compress/gzip

image/color

image/draw

image/color/palette

image/png

image/gif

image/jpeg

encoding/base64

encoding/base32

encoding/xml

encoding/asn1

encoding/pem

encoding/ascii85

encoding/csv

encoding/hex

encoding/json

encoding/binary

encoding/gob

debug/pe

debug/plan9obj

debug/dwarf

debug/elf

debug/gosym

debug/macho

math/rand

math/big

math/cmplx

3. In your ~/.vim/ftplugin/go.vim, add the following:

fun! ReadMan()

" Assign current file under cursor to a script variable:

let s:man_word = expand('<cword>')

let s:full_word = system('~/bin/godoc.sh '. s:man_word)

:exe ":Godoc " . s:full_word

endfun

" Map the K key to the ReadMan function:

map K :call ReadMan()<CR>

This will take the keyword under cursor, expanded using the shell script, and call :Godoc on it. This takes care of subpackages

November 14, 2014

ios validate self signed certificate

http://stackoverflow.com/questions/10979922/ios-and-ssl-unable-to-validate-self-signed-server-certificate

Quote:

I did figure out how to resolve this issue.
I ended up comparing the client and server trust certificates, byte-by-byte. Although there could be another way to resolve such issues of self-signed certificate, but for this solution did work. Here is how I'm doing comparison of the client and server certificates, byte-by-byte, using their CFData objects(you can also reference 'AdvancedURLConnections' example code provided by Apple):

success = NO;
        pServerCert = SecTrustGetLeafCertificate(trust);
        if (clientCert != NULL) {
            CFDataRef       clientCertData;
            CFDataRef       serverCertData;

            clientCertData = SecCertificateCopyData(clientCert);
            serverCertData   = SecCertificateCopyData(pServerCert);

            assert(clientCertData != NULL);
            assert(serverCertData   != NULL);

            success = CFEqual(clientCertData, serverCertData);

            CFRelease(clientCertData);
            CFRelease(serverCertData);
        }
        if (success) {
            [[challenge sender] useCredential:credential forAuthenticationChallenge:challenge];
            [self printLogToConsole:@"Success! Trust validation successful."];
        } else {
            [self printLogToConsole:@"Failed! Trust evaluation failed for service root certificate.\n"];
            [[challenge sender] cancelAuthenticationChallenge:challenge];
        }

Hope this will help someone, who is looking for solution of similar issue,

November 12, 2014

the ffmpeg command to explode video into still images

ffmpeg.exe -i IMG_0278.MOV -ss 0 -t 1 -f image2 -sameq -vcodec mjpeg "img-%03d.jpg"

-ss: start time, 0 means starting at 0 second mark

-t : number of seconds to explode

November 7, 2014

A great place to look for old Linux iso files

http://ftp.caliu.cat/pub/distribucions/yellowdog/releases/yellowdog-4.0/en/os/SRPMS/

November 6, 2014

vim and error list

If you have text file that contains the list of errors with line positions, you can tell vim to use that to help you navigate through the list.

1. Edit the list to the following format (suppose it is named "errors.txt")
xxxx.c:123: Warning/Error/Info rest-of-the-text
where
xxxx.c is the source code file name
123 is the line number

2. vim -q errors.txt

3. now you can type ":cw" to open the "quickfix" window which list the errors, and use ":cn" and ":cp" to go through them. Mapping these to a short cut key will make life easier. I map mine to Ctrl-j and Ctrl-k for down and up (copy and the paste the following to your ~/.vimrc file)

map <C-J> :cn<CR>
map <C-K> :cp<CR>

November 5, 2014

check ip address owner

For an U.S IP address, you can go to the following site:

http://whois.arin.net

and put the IP address in the search box of top right corner, and you can get more info on it.

Once you find the owner, you can click on "Related Networks" to find all the IP addresses that owner owns.

November 3, 2014

How to dump Mac OS X dns cache

DNS cache information is not managed by Directory Services, contrary to popular opinion on this site. It's managed by mDNSResponder, and the man page contains the answer to your question:

A SIGINFO signal will dump a snapshot summary of the internal state to /var/log/system.log:

   % sudo killall -INFO mDNSResponder

October 31, 2014

Windows Active Directory (AD) LDAP binding account

The common way to bind to AD as an LDAP server is to use "Distinguished Name(DN)" and Password. The DN usually is in the form of: CN=username,CN=Users,DC=yourdomain,DC=com

To find out DN, you can use Sysinternal's Active Directory Explorer to connect to AD and browse to the user to find out.

According to this post on stackoverflow, http://serverfault.com/questions/497368/ldap-activedirectory-binddn-syntax, you can also use UPN, which typically has the value of:

<sAMAccountName>@<domain FQDN>