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  • Caching issue with Centos forwarding DNS server

    - by Paddington
    I installed a Forwarding DNS server on Centos 5.10 and it is resolving addresses e.g google.com. When I stopped named (service named stop) and tried to dig (dig @localhost A google.com) there was a failure to resolve the address. I checked and see the caching daemon nscd is running. Does this mean the server is not caching at all? How can I get it to cache? named.conf options { // Those options should be used carefully because they disable port // randomization // query-source port 53; // query-source-v6 port 53; // Put files that named is allowed to write in the data/ directory: listen-on port 53 {127.0.0.1; 10.0.0.4;}; directory "/var/named"; // the default dump-file "/var/named/chroot/var/named/data/cache_dump.db"; statistics-file "/var/named/chroot/var/named/data/named_stats.txt"; memstatistics-file "/var/named/chroot/var/named/data/named_mem_stats.txt"; // allow-query {localhost; 192.168.0.0/24; 10.0.0.0/8;}; recursion yes; //allow-query { localhost; 10.0.0.0/8;}; allow-query { localhost; any; }; allow-query-cache { localhost; any; }; forward only; forwarders {8.8.8.8; 8.8.4.4;}; dnssec-enable yes; // dnssec-lookaside auto; /* Path to ISC DLV key */ // bindkeys-file "/etc/named.iscdlv.key"; // managed-keys-directory "/var/named/dynamic"; }; logging { channel default_debug { file "data/named.run"; severity dynamic; }; }; **

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  • Apache php_ldap.dll error

    - by pluke
    I have apache with php 5.4 installed on a Windows 7 64bit machine. When I restart Apache I get the following: PHP Startup: Unable to load dynamic library 'c:/PHP54/ext\\php_ldap.dll' - %1 is not a valid Win32 application The file is present but LDAP doesn't work, any idea what I am doing wrong? php.ini has the following settings [ldap] ; Sets the maximum number of open links or -1 for unlimited. ldap.max_links = -1 ;extension=php_interbase.dll extension=php_ldap.dll extension=php_mbstring.dll

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  • Pretty/powerful CMD alternatives?

    - by w1sh
    I'm a Windows user and am just getting my feet wet with Python and some other languages. I keep having to deal with the Command Prompt, and it doesn't bother me, but I'm sure there are some free alternatives out there that look a lot nicer and probably pack a bigger punch. Any suggestions would be nice. Thanks!

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  • Summing of total with dynamics rows coming external datasource

    - by Gainster
    I am using Excel 2010 and retrieving data from SQL analysis service. When I refresh the data from Excel, the rows all refresh as they are bound to an external datasource. I am adding a separate column with a formula to sum the totals. With an increment or decrement of these rows, the alignment of custom columns goes out. How can I resolve this problem that summing of values become dynamic with adding and removal of rows?

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  • Which guide do you recommend on setting up Nginx

    - by Saif Bechan
    I am setting up an LEMP (Nginx, MySQL, PHP on Linux) from scratch. There are a lot of guides available online in all different forms. Now I want a setup with virtual hosts, and only serve dynamic content (PHP). My static files(images,css,js) are on a CDN. Do you know of a good guide on setting up the LEMP installation.

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  • nginx support for .htaccess / rewrite rules? Differences from Apache?

    - by anonymous coward
    I've been working with Apache http servers for quite some time, and finally making the move to static-content servers alongside the others dynamic-content machines. I was wondering, does nginx support ".htaccess" files, and things like mod_rewrite? As I'm very used to the syntax, I was wondering what the (syntax) differences were, and what the learning curve is like moving from Apache configs to nginx.

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  • How can a cloud be created from virtualization or how is it different from virtualization?

    - by Echelon
    I have heard that virtualization is the basis of Cloud,so If i have a machine with xen as virtualizing environment and many vms running on it,then can that be called as a cloud. Is it true that vms that scale based on load and memory is called cloud and vms that do not scale is called as just virtualization! How can a vm scale??Based on my understanding for xen once we fix cpu and ram,it cant go beyond that (am aware of Dynamic memory Management) so how it really scale?.Can any one please clarify this

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  • How to set start screen tiles' language in Windows 8

    - by Robert Koritnik
    I've installed English Windows 8 x64 on my notebook and selected Slovenian as locale during installation. The problem I'm having now is that my tiles on start screen display in Slovenian even though my installation is English. I've also edited languages, adding English (British) on the list and putting it on top of Slovenian, but tiles still use Slovenian... All previous Windows versions were able to have English UI with a particular locale for input, time, dates, currency etc. How can I do the same in Windows 8?

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  • What would a new web development tool need to succeed?

    - by boost
    If one wanted to bring a new web development tool to market, what would it have to be able to do that would differentiate it enough from all the others to attract people's attention? In what areas are all the other frameworks and languages falling down, such that if a new product addressed those issues, it would stand a chance of being adopted by significant user community?

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  • Monitor Web Browsing Habits of Networked Users

    - by Linus
    I've been tasked with generating dynamic, real-time (or as close to real-time as possible) reports on the web browsing habits of my users. Basically we need a way of charting the amount of time user X spends on website Y. The last stop on our network is a FreeBSD box that is currently generating netflow data. I've reviewed some netflow analyzers but none seem to meet our needs. Any tools or suggestions will be greatly appreciated.

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  • How To: UiBinder + GWT MVP + multiple independent display areas

    - by Prt Yz
    I am using GWT MVP and UiBinder to create an app with a DockLayoutPanel. I want the north and south docks to be static, containing buttons and links. I want to have dynamic views in the center and two different areas of the east dock. As these dynamic areas should be independent of each other, I am setting up different ActivityMapper and ActivityManager's for each dynamic display area; center, east-top, and east-bottom. How can I independently initialize these 3 different display areas when the application is loaded? How can I switch from one Activity to another in one display area without affecting the other areas? When I use the the PlaceController's goTo to switch from one Place to another in one area, the other area's Activity is stopped. Mayday, please help, mayday! The following is some of my code: AppViewImpl.ui.xml <g:DockLayoutPanel styleName="{style.dockPanel}" unit="PX" width="975px" height="100%"> <!-- DOCK PANEL EAST --> <g:east size="220"> <g:LayoutPanel styleName="{style.eastPanel}"> <g:layer left="0px" width="220px" top="0px" height="105px"> <g:SimpleLayoutPanel ui:field="topRightPanel"/> </g:layer> <g:layer left="0px" width="220px" top="110px" height="340px"> <g:InlineLabel styleName="{style.label}" text="ANOTHER DISPLAY AREA"/> </g:layer> </g:LayoutPanel> </g:east> <!-- DOCK PANEL NORTH --> <g:north size="110"> <g:LayoutPanel styleName="{style.northPanel}"> <g:layer left="0px" width="755px" top="0px" height="105px"> <g:InlineLabel styleName="{style.label}" text="NORTH PANEL"/> </g:layer> </g:LayoutPanel> </g:north> <!-- DOCK PANEL SOUTH --> <g:south size="20"> <g:LayoutPanel styleName="{style.southPanel}"> <g:layer left="0px" width="755px" top="0px" height="20px"> <g:InlineLabel styleName="{style.label}" text="SOUTH PANEL"/> </g:layer> </g:LayoutPanel> </g:south> <!-- DOCK PANEL CENTER --> <g:center> <g:SimpleLayoutPanel ui:field="mainPanel" /> </g:center> </g:DockLayoutPanel> MyModule.java public class MyModule implements EntryPoint { private Place defaultPlace = new DefaultPlace(""); public void onModuleLoad() { // Create ClientFactory using deferred binding so we can replace with // different impls in gwt.xml ClientFactory clientFactory = GWT.create(ClientFactory.class); EventBus eventBus = clientFactory.getEventBus(); PlaceController placeController = clientFactory.getPlaceController(); // Start ActivityManager for the main widget with our ActivityMapper ActivityMapper topRightActivityMapper = new TopRightActivityMapper(clientFactory); ActivityManager topRightActivityManager = new ActivityManager(topRightActivityMapper, eventBus); topRightActivityManager.setDisplay(clientFactory.getAppView().getTopRightPanel()); // Start ActivityManager for the main widget with our ActivityMapper ActivityMapper mainActivityMapper = new AppActivityMapper(clientFactory); ActivityManager mainActivityManager = new ActivityManager(mainActivityMapper, eventBus); mainActivityManager.setDisplay(clientFactory.getAppView().getMainPanel()); // Start PlaceHistoryHandler with our PlaceHistoryMapper AppPlaceHistoryMapper historyMapper = GWT .create(AppPlaceHistoryMapper.class); PlaceHistoryHandler historyHandler = new PlaceHistoryHandler(historyMapper); historyHandler.register(placeController, eventBus, defaultPlace); RootLayoutPanel.get().add(clientFactory.getAppView()); // Goes to place represented on URL or default place historyHandler.handleCurrentHistory(); new AppController(clientFactory); } } AppController.java public class AppController implements AppView.Presenter { private ClientFactory clientFactory; AppController(ClientFactory clientFactory){ this.clientFactory = clientFactory; goTo(new TopRightAPlace("")); } @Override public void goTo(Place place) { clientFactory.getPlaceController().goTo(place); } } TopRightAViewImpl.java public class TopRightAViewImpl extends Composite implements TopRightAView { interface Binder extends UiBinder<Widget, TopRightAViewImpl> { } private static final Binder binder = GWT.create(Binder.class); private Presenter listener; @UiField Button button; public TopRightAViewImpl() { initWidget(binder.createAndBindUi(this)); } @Override public void setName(String name) { button.setHTML(name); } @Override public void setPresenter(Presenter listener) { this.listener = listener; } @UiHandler("button") void onButtonClick(ClickEvent event) { listener.goTo(some other place); } }

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  • Having trouble on mouse over tabs

    - by user225269
    I downloaded a webpage template from the internet because I don't know how to design webpage on photoshop. This was the one I downloaded: http://www.freewebtemplates.com/download/templates/9839 And modified it. And I have this code for mouse over tabs from dynamic drive. But doesn't seem to be working with the template that I downloaded. Here is my current code: <script src="mouseovertabs.js" type="text/javascript"> </script> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <title>Designed by Web Page Templates</title> <meta name="keywords" content="" /> <meta name="description" content="" /> <link href="default.css" rel="stylesheet" type="text/css" /> </head> <body> <table border="0" align="center" cellpadding="0" cellspacing="0" class="bg1"> <tr> <td class="text1" style="height: 50px;">xd627 information management system</td> </tr> <tr> <div id="mytabsmenu" class="tabsmenuclass"> <td class="bg5"><table border="0" cellspacing="0" cellpadding="0" style="height: 62px; padding-top: 15px;"> <tr align="center"> <td><ul><li><a href="index.html" class="link1">Homepage</a></li></td> <td><li><a href="RegStuds.php" class="link1">Database</a></li></td> <td><li><a href="#" class="link1">About</a></li> </ul></td> <a href="submenucontents.htm" style="visibility:hidden">Sub Menu contents</a> <div id="mysubmenuarea" class="tabsmenucontentclass"> <!--1st link within submenu container should point to the external submenu contents file--> <a href="submenucontents.htm" style="visibility:hidden">Sub Menu contents</a> </div> <script type="text/javascript"> //mouseovertabsmenu.init("tabs_container_id", "submenu_container_id", "bool_hidecontentsmouseout") mouseovertabsmenu.init("mytabsmenu", "mysubmenuarea", true) </script> </div> What might be wrong here,its working perfectly with my previous one, but with no layout at all: <script src="mouseovertabs.js" type="text/javascript"> /*********************************************** * Mouseover Tabs Menu- (c) Dynamic Drive DHTML code library (www.dynamicdrive.com) * This notice MUST stay intact for legal use * Visit Dynamic Drive at http://www.dynamicdrive.com/ for this script and 100s more ***********************************************/ </script> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Untitled Document</title> </head> <body> <div id="mytabsmenu" class="tabsmenuclass"> <ul> <li><a href="" rel="gotsubmenu[selected]">Database Manipulation</a></li> <li><a href="" rel="gotsubmenu" >Register User</a></li> <li><a href="loginform2.php" rel="gotsubmenu" >Logout</a></li> <li><a href=""></a></li> </ul> </div> <div id="mysubmenuarea" class="tabsmenucontentclass"> <!--1st link within submenu container should point to the external submenu contents file--> <a href="submenucontents.htm" style="visibility:hidden">Sub Menu contents</a> </div> <script type="text/javascript"> //mouseovertabsmenu.init("tabs_container_id", "submenu_container_id", "bool_hidecontentsmouseout") mouseovertabsmenu.init("mytabsmenu", "mysubmenuarea", true) </script> </body> </html>

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  • Need help getting DIV inside DIV to stretch to width of contents in Firefox

    - by bj.
    I am using a layout similar to the one from Dynamic Drive here: http://www.dynamicdrive.com/style/layouts/item/css-right-frame-layout/ The main content area (white) has overflow set to auto. I have given the innerTube inside this main content area a border. However if the contents within this innerTube are greater than the width of the main content area, a horizontal scroll bar will appear as expected, but in Firefox these contents will 'overlap' the border and go off screen (can be retrieved by scrolling horizontally). In other words, the right hand border remains in place, and the content just goes over the op of it, and disappears behind the right hand column. In IE it behaves exactly as I want - the content pushes the border off screen to be visible only once you scroll over there. I guess the easiest thing is to paste the source code here. If you copy it into a blank file you'll see what I mean. I've just used one really long word to replicate what happens if a wide image is there instead. Thanks in advance to anyone who can help me out. <!--Force IE6 into quirks mode with this comment tag--> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <style type="text/css"> body{ margin: 0; padding: 0; border: 0; overflow: hidden; height: 100%; max-height: 100%; } #framecontent{ position: absolute; top: 0; bottom: 0; right: 0; width: 200px; /*Width of frame div*/ height: 100%; overflow: hidden; /*Disable scrollbars. Set to "scroll" to enable*/ background: #cccccc; color: white; } #maincontent{ position: fixed; top: 0; left: 0; right: 200px; /*Set right value to WidthOfFrameDiv*/ bottom: 0; overflow: auto; background: #fff; } .innertube{ margin: 15px; /*Margins for inner DIV inside each DIV (to provide padding)*/ } .innertubeWithBorder { margin: 15px; border: solid 1px #666666; } * html body{ /*IE6 hack*/ padding: 0 200px 0 0; /*Set value to (0 WidthOfFrameDiv 0 0)*/ } * html #maincontent{ /*IE6 hack*/ height: 100%; width: 100%; } </style> </head> <body> <div id="framecontent"> <div class="innertube"> <h1>CSS Right Frame Layout</h1> <h3>Sample text here</h3> </div> </div> <div id="maincontent"> <div class="innertubeWithBorder"> <h1>Dynamic Drive CSS Library</h1> <p>AReallyLongWordWhichIsSimilarToHavingAnImageWithWidthGreaterThanTheWidthOfThisDivToShowOverFlowProblemWithBorderSoIfYouResizeThisWindowNarrowerYouWillSeeWhatIMeanWorksFineInIEButNotFirefox</p> <p>So I want that border over there ------> to dissappear behind the right hand column like it does in IE, and be visible once you use the scrollbar below and scroll to the right</p> <p style="text-align: center">Credits: <a href="http://www.dynamicdrive.com/style/">Dynamic Drive CSS Library</a></p> </div> </div> </body> </html>

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  • Best way of learning Python + GUI when coming from .NET

    - by Oscar Mederos
    I've been developing applications in C# / VB.NET for about 3-4 years (.NET Framework v2.0, 3.5, 4). I have also developed some command-line applications or scripts in C, and Python under Linux. Sometimes I need to develop my applications in another languages, like Python, but the problem thing is that lots of those applications require a GUI. Maybe not a too complex one, but it does require some windows with buttons, text boxes, list boxes,... What books/tips/tutorials do you suggest me to start working with that language and be able to deploy my deliverables not only in .NET? Note: Learning python is not the big deal here, because I already know the basic of it. I just want to focus on the GUI. Maybe this question should be on UI instead of here? If so, please, migrate it :)

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  • Toorcon14

    - by danx
    Toorcon 2012 Information Security Conference San Diego, CA, http://www.toorcon.org/ Dan Anderson, October 2012 It's almost Halloween, and we all know what that means—yes, of course, it's time for another Toorcon Conference! Toorcon is an annual conference for people interested in computer security. This includes the whole range of hackers, computer hobbyists, professionals, security consultants, press, law enforcement, prosecutors, FBI, etc. We're at Toorcon 14—see earlier blogs for some of the previous Toorcon's I've attended (back to 2003). This year's "con" was held at the Westin on Broadway in downtown San Diego, California. The following are not necessarily my views—I'm just the messenger—although I could have misquoted or misparaphrased the speakers. Also, I only reviewed some of the talks, below, which I attended and interested me. MalAndroid—the Crux of Android Infections, Aditya K. Sood Programming Weird Machines with ELF Metadata, Rebecca "bx" Shapiro Privacy at the Handset: New FCC Rules?, Valkyrie Hacking Measured Boot and UEFI, Dan Griffin You Can't Buy Security: Building the Open Source InfoSec Program, Boris Sverdlik What Journalists Want: The Investigative Reporters' Perspective on Hacking, Dave Maas & Jason Leopold Accessibility and Security, Anna Shubina Stop Patching, for Stronger PCI Compliance, Adam Brand McAfee Secure & Trustmarks — a Hacker's Best Friend, Jay James & Shane MacDougall MalAndroid—the Crux of Android Infections Aditya K. Sood, IOActive, Michigan State PhD candidate Aditya talked about Android smartphone malware. There's a lot of old Android software out there—over 50% Gingerbread (2.3.x)—and most have unpatched vulnerabilities. Of 9 Android vulnerabilities, 8 have known exploits (such as the old Gingerbread Global Object Table exploit). Android protection includes sandboxing, security scanner, app permissions, and screened Android app market. The Android permission checker has fine-grain resource control, policy enforcement. Android static analysis also includes a static analysis app checker (bouncer), and a vulnerablity checker. What security problems does Android have? User-centric security, which depends on the user to grant permission and make smart decisions. But users don't care or think about malware (the're not aware, not paranoid). All they want is functionality, extensibility, mobility Android had no "proper" encryption before Android 3.0 No built-in protection against social engineering and web tricks Alternative Android app markets are unsafe. Simply visiting some markets can infect Android Aditya classified Android Malware types as: Type A—Apps. These interact with the Android app framework. For example, a fake Netflix app. Or Android Gold Dream (game), which uploads user files stealthy manner to a remote location. Type K—Kernel. Exploits underlying Linux libraries or kernel Type H—Hybrid. These use multiple layers (app framework, libraries, kernel). These are most commonly used by Android botnets, which are popular with Chinese botnet authors What are the threats from Android malware? These incude leak info (contacts), banking fraud, corporate network attacks, malware advertising, malware "Hackivism" (the promotion of social causes. For example, promiting specific leaders of the Tunisian or Iranian revolutions. Android malware is frequently "masquerated". That is, repackaged inside a legit app with malware. To avoid detection, the hidden malware is not unwrapped until runtime. The malware payload can be hidden in, for example, PNG files. Less common are Android bootkits—there's not many around. What they do is hijack the Android init framework—alteering system programs and daemons, then deletes itself. For example, the DKF Bootkit (China). Android App Problems: no code signing! all self-signed native code execution permission sandbox — all or none alternate market places no robust Android malware detection at network level delayed patch process Programming Weird Machines with ELF Metadata Rebecca "bx" Shapiro, Dartmouth College, NH https://github.com/bx/elf-bf-tools @bxsays on twitter Definitions. "ELF" is an executable file format used in linking and loading executables (on UNIX/Linux-class machines). "Weird machine" uses undocumented computation sources (I think of them as unintended virtual machines). Some examples of "weird machines" are those that: return to weird location, does SQL injection, corrupts the heap. Bx then talked about using ELF metadata as (an uintended) "weird machine". Some ELF background: A compiler takes source code and generates a ELF object file (hello.o). A static linker makes an ELF executable from the object file. A runtime linker and loader takes ELF executable and loads and relocates it in memory. The ELF file has symbols to relocate functions and variables. ELF has two relocation tables—one at link time and another one at loading time: .rela.dyn (link time) and .dynsym (dynamic table). GOT: Global Offset Table of addresses for dynamically-linked functions. PLT: Procedure Linkage Tables—works with GOT. The memory layout of a process (not the ELF file) is, in order: program (+ heap), dynamic libraries, libc, ld.so, stack (which includes the dynamic table loaded into memory) For ELF, the "weird machine" is found and exploited in the loader. ELF can be crafted for executing viruses, by tricking runtime into executing interpreted "code" in the ELF symbol table. One can inject parasitic "code" without modifying the actual ELF code portions. Think of the ELF symbol table as an "assembly language" interpreter. It has these elements: instructions: Add, move, jump if not 0 (jnz) Think of symbol table entries as "registers" symbol table value is "contents" immediate values are constants direct values are addresses (e.g., 0xdeadbeef) move instruction: is a relocation table entry add instruction: relocation table "addend" entry jnz instruction: takes multiple relocation table entries The ELF weird machine exploits the loader by relocating relocation table entries. The loader will go on forever until told to stop. It stores state on stack at "end" and uses IFUNC table entries (containing function pointer address). The ELF weird machine, called "Brainfu*k" (BF) has: 8 instructions: pointer inc, dec, inc indirect, dec indirect, jump forward, jump backward, print. Three registers - 3 registers Bx showed example BF source code that implemented a Turing machine printing "hello, world". More interesting was the next demo, where bx modified ping. Ping runs suid as root, but quickly drops privilege. BF modified the loader to disable the library function call dropping privilege, so it remained as root. Then BF modified the ping -t argument to execute the -t filename as root. It's best to show what this modified ping does with an example: $ whoami bx $ ping localhost -t backdoor.sh # executes backdoor $ whoami root $ The modified code increased from 285948 bytes to 290209 bytes. A BF tool compiles "executable" by modifying the symbol table in an existing ELF executable. The tool modifies .dynsym and .rela.dyn table, but not code or data. Privacy at the Handset: New FCC Rules? "Valkyrie" (Christie Dudley, Santa Clara Law JD candidate) Valkyrie talked about mobile handset privacy. Some background: Senator Franken (also a comedian) became alarmed about CarrierIQ, where the carriers track their customers. Franken asked the FCC to find out what obligations carriers think they have to protect privacy. The carriers' response was that they are doing just fine with self-regulation—no worries! Carriers need to collect data, such as missed calls, to maintain network quality. But carriers also sell data for marketing. Verizon sells customer data and enables this with a narrow privacy policy (only 1 month to opt out, with difficulties). The data sold is not individually identifiable and is aggregated. But Verizon recommends, as an aggregation workaround to "recollate" data to other databases to identify customers indirectly. The FCC has regulated telephone privacy since 1934 and mobile network privacy since 2007. Also, the carriers say mobile phone privacy is a FTC responsibility (not FCC). FTC is trying to improve mobile app privacy, but FTC has no authority over carrier / customer relationships. As a side note, Apple iPhones are unique as carriers have extra control over iPhones they don't have with other smartphones. As a result iPhones may be more regulated. Who are the consumer advocates? Everyone knows EFF, but EPIC (Electrnic Privacy Info Center), although more obsecure, is more relevant. What to do? Carriers must be accountable. Opt-in and opt-out at any time. Carriers need incentive to grant users control for those who want it, by holding them liable and responsible for breeches on their clock. Location information should be added current CPNI privacy protection, and require "Pen/trap" judicial order to obtain (and would still be a lower standard than 4th Amendment). Politics are on a pro-privacy swing now, with many senators and the Whitehouse. There will probably be new regulation soon, and enforcement will be a problem, but consumers will still have some benefit. Hacking Measured Boot and UEFI Dan Griffin, JWSecure, Inc., Seattle, @JWSdan Dan talked about hacking measured UEFI boot. First some terms: UEFI is a boot technology that is replacing BIOS (has whitelisting and blacklisting). UEFI protects devices against rootkits. TPM - hardware security device to store hashs and hardware-protected keys "secure boot" can control at firmware level what boot images can boot "measured boot" OS feature that tracks hashes (from BIOS, boot loader, krnel, early drivers). "remote attestation" allows remote validation and control based on policy on a remote attestation server. Microsoft pushing TPM (Windows 8 required), but Google is not. Intel TianoCore is the only open source for UEFI. Dan has Measured Boot Tool at http://mbt.codeplex.com/ with a demo where you can also view TPM data. TPM support already on enterprise-class machines. UEFI Weaknesses. UEFI toolkits are evolving rapidly, but UEFI has weaknesses: assume user is an ally trust TPM implicitly, and attached to computer hibernate file is unprotected (disk encryption protects against this) protection migrating from hardware to firmware delays in patching and whitelist updates will UEFI really be adopted by the mainstream (smartphone hardware support, bank support, apathetic consumer support) You Can't Buy Security: Building the Open Source InfoSec Program Boris Sverdlik, ISDPodcast.com co-host Boris talked about problems typical with current security audits. "IT Security" is an oxymoron—IT exists to enable buiness, uptime, utilization, reporting, but don't care about security—IT has conflict of interest. There's no Magic Bullet ("blinky box"), no one-size-fits-all solution (e.g., Intrusion Detection Systems (IDSs)). Regulations don't make you secure. The cloud is not secure (because of shared data and admin access). Defense and pen testing is not sexy. Auditors are not solution (security not a checklist)—what's needed is experience and adaptability—need soft skills. Step 1: First thing is to Google and learn the company end-to-end before you start. Get to know the management team (not IT team), meet as many people as you can. Don't use arbitrary values such as CISSP scores. Quantitive risk assessment is a myth (e.g. AV*EF-SLE). Learn different Business Units, legal/regulatory obligations, learn the business and where the money is made, verify company is protected from script kiddies (easy), learn sensitive information (IP, internal use only), and start with low-hanging fruit (customer service reps and social engineering). Step 2: Policies. Keep policies short and relevant. Generic SANS "security" boilerplate policies don't make sense and are not followed. Focus on acceptable use, data usage, communications, physical security. Step 3: Implementation: keep it simple stupid. Open source, although useful, is not free (implementation cost). Access controls with authentication & authorization for local and remote access. MS Windows has it, otherwise use OpenLDAP, OpenIAM, etc. Application security Everyone tries to reinvent the wheel—use existing static analysis tools. Review high-risk apps and major revisions. Don't run different risk level apps on same system. Assume host/client compromised and use app-level security control. Network security VLAN != segregated because there's too many workarounds. Use explicit firwall rules, active and passive network monitoring (snort is free), disallow end user access to production environment, have a proxy instead of direct Internet access. Also, SSL certificates are not good two-factor auth and SSL does not mean "safe." Operational Controls Have change, patch, asset, & vulnerability management (OSSI is free). For change management, always review code before pushing to production For logging, have centralized security logging for business-critical systems, separate security logging from administrative/IT logging, and lock down log (as it has everything). Monitor with OSSIM (open source). Use intrusion detection, but not just to fulfill a checkbox: build rules from a whitelist perspective (snort). OSSEC has 95% of what you need. Vulnerability management is a QA function when done right: OpenVas and Seccubus are free. Security awareness The reality is users will always click everything. Build real awareness, not compliance driven checkbox, and have it integrated into the culture. Pen test by crowd sourcing—test with logging COSSP http://www.cossp.org/ - Comprehensive Open Source Security Project What Journalists Want: The Investigative Reporters' Perspective on Hacking Dave Maas, San Diego CityBeat Jason Leopold, Truthout.org The difference between hackers and investigative journalists: For hackers, the motivation varies, but method is same, technological specialties. For investigative journalists, it's about one thing—The Story, and they need broad info-gathering skills. J-School in 60 Seconds: Generic formula: Person or issue of pubic interest, new info, or angle. Generic criteria: proximity, prominence, timeliness, human interest, oddity, or consequence. Media awareness of hackers and trends: journalists becoming extremely aware of hackers with congressional debates (privacy, data breaches), demand for data-mining Journalists, use of coding and web development for Journalists, and Journalists busted for hacking (Murdock). Info gathering by investigative journalists include Public records laws. Federal Freedom of Information Act (FOIA) is good, but slow. California Public Records Act is a lot stronger. FOIA takes forever because of foot-dragging—it helps to be specific. Often need to sue (especially FBI). CPRA is faster, and requests can be vague. Dumps and leaks (a la Wikileaks) Journalists want: leads, protecting ourselves, our sources, and adapting tools for news gathering (Google hacking). Anonomity is important to whistleblowers. They want no digital footprint left behind (e.g., email, web log). They don't trust encryption, want to feel safe and secure. Whistleblower laws are very weak—there's no upside for whistleblowers—they have to be very passionate to do it. Accessibility and Security or: How I Learned to Stop Worrying and Love the Halting Problem Anna Shubina, Dartmouth College Anna talked about how accessibility and security are related. Accessibility of digital content (not real world accessibility). mostly refers to blind users and screenreaders, for our purpose. Accessibility is about parsing documents, as are many security issues. "Rich" executable content causes accessibility to fail, and often causes security to fail. For example MS Word has executable format—it's not a document exchange format—more dangerous than PDF or HTML. Accessibility is often the first and maybe only sanity check with parsing. They have no choice because someone may want to read what you write. Google, for example, is very particular about web browser you use and are bad at supporting other browsers. Uses JavaScript instead of links, often requiring mouseover to display content. PDF is a security nightmare. Executible format, embedded flash, JavaScript, etc. 15 million lines of code. Google Chrome doesn't handle PDF correctly, causing several security bugs. PDF has an accessibility checker and PDF tagging, to help with accessibility. But no PDF checker checks for incorrect tags, untagged content, or validates lists or tables. None check executable content at all. The "Halting Problem" is: can one decide whether a program will ever stop? The answer, in general, is no (Rice's theorem). The same holds true for accessibility checkers. Language-theoretic Security says complicated data formats are hard to parse and cannot be solved due to the Halting Problem. W3C Web Accessibility Guidelines: "Perceivable, Operable, Understandable, Robust" Not much help though, except for "Robust", but here's some gems: * all information should be parsable (paraphrasing) * if not parsable, cannot be converted to alternate formats * maximize compatibility in new document formats Executible webpages are bad for security and accessibility. They say it's for a better web experience. But is it necessary to stuff web pages with JavaScript for a better experience? A good example is The Drudge Report—it has hand-written HTML with no JavaScript, yet drives a lot of web traffic due to good content. A bad example is Google News—hidden scrollbars, guessing user input. Solutions: Accessibility and security problems come from same source Expose "better user experience" myth Keep your corner of Internet parsable Remember "Halting Problem"—recognize false solutions (checking and verifying tools) Stop Patching, for Stronger PCI Compliance Adam Brand, protiviti @adamrbrand, http://www.picfun.com/ Adam talked about PCI compliance for retail sales. Take an example: for PCI compliance, 50% of Brian's time (a IT guy), 960 hours/year was spent patching POSs in 850 restaurants. Often applying some patches make no sense (like fixing a browser vulnerability on a server). "Scanner worship" is overuse of vulnerability scanners—it gives a warm and fuzzy and it's simple (red or green results—fix reds). Scanners give a false sense of security. In reality, breeches from missing patches are uncommon—more common problems are: default passwords, cleartext authentication, misconfiguration (firewall ports open). Patching Myths: Myth 1: install within 30 days of patch release (but PCI §6.1 allows a "risk-based approach" instead). Myth 2: vendor decides what's critical (also PCI §6.1). But §6.2 requires user ranking of vulnerabilities instead. Myth 3: scan and rescan until it passes. But PCI §11.2.1b says this applies only to high-risk vulnerabilities. Adam says good recommendations come from NIST 800-40. Instead use sane patching and focus on what's really important. From NIST 800-40: Proactive: Use a proactive vulnerability management process: use change control, configuration management, monitor file integrity. Monitor: start with NVD and other vulnerability alerts, not scanner results. Evaluate: public-facing system? workstation? internal server? (risk rank) Decide:on action and timeline Test: pre-test patches (stability, functionality, rollback) for change control Install: notify, change control, tickets McAfee Secure & Trustmarks — a Hacker's Best Friend Jay James, Shane MacDougall, Tactical Intelligence Inc., Canada "McAfee Secure Trustmark" is a website seal marketed by McAfee. A website gets this badge if they pass their remote scanning. The problem is a removal of trustmarks act as flags that you're vulnerable. Easy to view status change by viewing McAfee list on website or on Google. "Secure TrustGuard" is similar to McAfee. Jay and Shane wrote Perl scripts to gather sites from McAfee and search engines. If their certification image changes to a 1x1 pixel image, then they are longer certified. Their scripts take deltas of scans to see what changed daily. The bottom line is change in TrustGuard status is a flag for hackers to attack your site. Entire idea of seals is silly—you're raising a flag saying if you're vulnerable.

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  • Translator by Moth v2

    - by Daniel Moth
    If you are looking for the full manual for this Windows Phone app you can find it here: "Translator by Moth". While the manual has no images (just text), in this post I will share images and if you like them, go get "Translator by Moth" from the Windows Phone marketplace. open the app from the app list or through a pinned tile (including secondary tiles for specific translations)    language picker (~40 languages)     "current" page     "saved" page    "about" page Like? Go get Translator by Moth! Comments about this post by Daniel Moth welcome at the original blog.

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  • How to use integrated Intel graphics instead of Nvidia graphics on MacBook Pro?

    - by Benjamin Geese
    I am running Ubuntu 12.04 64bit on MacBook Pro 15" 2010 (MacBookPro6,2) and I would like to use the integrated Intel graphics instead of the dedicated Nvidia graphics Ubuntu boots with on this machine. I am booting with UEFI, not REFIT or similar. I managed to switch to UEFI with the help of this page. This wiki page also contains tips on switching to Intel graphics which include some (for me) cryptic boot commands to grub. However if I follow the guide, my display stays just black. Currently, I am only looking for solution to use Intel graphics for Ubuntu to save power and keep my MacBook cool. Dynamic switching or stuff like that is not required.

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  • Determine arc-length of a Catmull-Rom spline

    - by Wouter
    I have a path that is defined by a concatenation of Catmull-Rom splines. I use the static method Vector2.CatmullRom in XNA that allows for interpolation between points with a value going from 0 to 1. Not every spline in this path has the same length. This causes speed differences if I let the weight go at a constant speed for every spline while proceeding along the path. I can remedy this by letting the speed of the weight be dependent on the length of the spline. How can I determine the length of such a spline? Should I just approximate by cutting the spline into 10 straight lines and sum their lengths? I'm using this for dynamic texture mapping on a generated mesh defined by splines.

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  • Dig Deeper in Windows Defrag via Command Prompt

    - by Matthew Guay
    Windows users have learned over the years that they need to keep their computers defragmented to keep running at top speed.  While Windows Vista and 7 automatically defrag your disks, here’s some ways you can dig deeper into Windows Defragmenter Latest Features How-To Geek ETC The 50 Best Registry Hacks that Make Windows Better The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Our Favorite Tech: What We’re Thankful For at How-To Geek Snowy Christmas House Personas Theme for Firefox The Mystic Underground Tunnel Wallpaper Ubunchu! – The Ubuntu Manga Available in Multiple Languages Breathe New Life into Your PlayStation 2 Peripherals by Hooking Them Up to Your Computer Move the Window Control Buttons to the Left Side in Windows Fun and Colorful Firefox Theme for Windows 7

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  • Google I/O 2010 - Go Programming

    Google I/O 2010 - Go Programming Google I/O 2010 - Go Programming Tech Talks Rob Pike, Russ Cox The Go Programming Language was released as an open source project in late 2009. This session will illustrate how programming in Go differs from other languages through a set of examples demonstrating features particular to Go. These include concurrency, embedded types, methods on any type, and program construction using interfaces. Very little time will be spent waiting for compilation. For all I/O 2010 sessions, please go to code.google.com From: GoogleDevelopers Views: 12 0 ratings Time: 56:11 More in Science & Technology

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  • 10 Easy DIY Father’s Day Gift Ideas

    - by Jason Fitzpatrick
    If you’re looking for a DIY gift for this Father’s Day that really shows off your maker ethic, this roundup of 10 DIY gifts is sure to have something to offer–fire pistons anyone? Courtesy of Make magazine, we find this 10 item roundup for great DIY projects you could hammer out between now and Father’s Day. The roundup includes everything from the mini-toolbox (really, more of a parts box) see in the photo here to more dynamic gifts like a homemade fire piston and a spider rifle. Hit up the link below to check out all the neat projects which, intended as a gift or not, will prompt you to head out to the workshop. Top 10: Easy DIY Gifts My Dad Would Dig [Make] HTG Explains: What Is RSS and How Can I Benefit From Using It? HTG Explains: Why You Only Have to Wipe a Disk Once to Erase It HTG Explains: Learn How Websites Are Tracking You Online

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  • If you had to reinvent a new syntax for regular expressions, what would it look like?

    - by Timwi
    Regular expressions as they are today are pretty much as concise and compact as they can be. Consequently, they are often criticised for being unreadable and hard to debug. If you had to reinvent a new syntax for regular expressions, what would it look like? Do you prefer the concise syntax they already have (or a different but similarly concise syntax)? If so, please justify why you think regular expressions deserve to be this concise, but your favourite programming language doesn’t (unless it’s Perl). Or do you think regular expressions should have a slightly more spaced-out syntax and look a bit more like operators and syntax elements normally do in programming languages? If so, provide examples of what you think the syntax should look like, and justify why it is better than the current syntax. Or do you think there shouldn’t even be a special syntax for regular expressions, and instead they should be constructed from syntax elements already present in the programming language? If so, give examples of a syntax that might be used to construct such regular expressions.

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  • Big Data – Buzz Words: Importance of Relational Database in Big Data World – Day 9 of 21

    - by Pinal Dave
    In yesterday’s blog post we learned what is HDFS. In this article we will take a quick look at the importance of the Relational Database in Big Data world. A Big Question? Here are a few questions I often received since the beginning of the Big Data Series - Does the relational database have no space in the story of the Big Data? Does relational database is no longer relevant as Big Data is evolving? Is relational database not capable to handle Big Data? Is it true that one no longer has to learn about relational data if Big Data is the final destination? Well, every single time when I hear that one person wants to learn about Big Data and is no longer interested in learning about relational database, I find it as a bit far stretched. I am not here to give ambiguous answers of It Depends. I am personally very clear that one who is aspiring to become Big Data Scientist or Big Data Expert they should learn about relational database. NoSQL Movement The reason for the NoSQL Movement in recent time was because of the two important advantages of the NoSQL databases. Performance Flexible Schema In personal experience I have found that when I use NoSQL I have found both of the above listed advantages when I use NoSQL database. There are instances when I found relational database too much restrictive when my data is unstructured as well as they have in the datatype which my Relational Database does not support. It is the same case when I have found that NoSQL solution performing much better than relational databases. I must say that I am a big fan of NoSQL solutions in the recent times but I have also seen occasions and situations where relational database is still perfect fit even though the database is growing increasingly as well have all the symptoms of the big data. Situations in Relational Database Outperforms Adhoc reporting is the one of the most common scenarios where NoSQL is does not have optimal solution. For example reporting queries often needs to aggregate based on the columns which are not indexed as well are built while the report is running, in this kind of scenario NoSQL databases (document database stores, distributed key value stores) database often does not perform well. In the case of the ad-hoc reporting I have often found it is much easier to work with relational databases. SQL is the most popular computer language of all the time. I have been using it for almost over 10 years and I feel that I will be using it for a long time in future. There are plenty of the tools, connectors and awareness of the SQL language in the industry. Pretty much every programming language has a written drivers for the SQL language and most of the developers have learned this language during their school/college time. In many cases, writing query based on SQL is much easier than writing queries in NoSQL supported languages. I believe this is the current situation but in the future this situation can reverse when No SQL query languages are equally popular. ACID (Atomicity Consistency Isolation Durability) – Not all the NoSQL solutions offers ACID compliant language. There are always situations (for example banking transactions, eCommerce shopping carts etc.) where if there is no ACID the operations can be invalid as well database integrity can be at risk. Even though the data volume indeed qualify as a Big Data there are always operations in the application which absolutely needs ACID compliance matured language. The Mixed Bag I have often heard argument that all the big social media sites now a days have moved away from Relational Database. Actually this is not entirely true. While researching about Big Data and Relational Database, I have found that many of the popular social media sites uses Big Data solutions along with Relational Database. Many are using relational databases to deliver the results to end user on the run time and many still uses a relational database as their major backbone. Here are a few examples: Facebook uses MySQL to display the timeline. (Reference Link) Twitter uses MySQL. (Reference Link) Tumblr uses Sharded MySQL (Reference Link) Wikipedia uses MySQL for data storage. (Reference Link) There are many for prominent organizations which are running large scale applications uses relational database along with various Big Data frameworks to satisfy their various business needs. Summary I believe that RDBMS is like a vanilla ice cream. Everybody loves it and everybody has it. NoSQL and other solutions are like chocolate ice cream or custom ice cream – there is a huge base which loves them and wants them but not every ice cream maker can make it just right  for everyone’s taste. No matter how fancy an ice cream store is there is always plain vanilla ice cream available there. Just like the same, there are always cases and situations in the Big Data’s story where traditional relational database is the part of the whole story. In the real world scenarios there will be always the case when there will be need of the relational database concepts and its ideology. It is extremely important to accept relational database as one of the key components of the Big Data instead of treating it as a substandard technology. Ray of Hope – NewSQL In this module we discussed that there are places where we need ACID compliance from our Big Data application and NoSQL will not support that out of box. There is a new termed coined for the application/tool which supports most of the properties of the traditional RDBMS and supports Big Data infrastructure – NewSQL. Tomorrow In tomorrow’s blog post we will discuss about NewSQL. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • Ancillary Objects: Separate Debug ELF Files For Solaris

    - by Ali Bahrami
    We introduced a new object ELF object type in Solaris 11 Update 1 called the Ancillary Object. This posting describes them, using material originally written during their development, the PSARC arc case, and the Solaris Linker and Libraries Manual. ELF objects contain allocable sections, which are mapped into memory at runtime, and non-allocable sections, which are present in the file for use by debuggers and observability tools, but which are not mapped or used at runtime. Typically, all of these sections exist within a single object file. Ancillary objects allow them to instead go into a separate file. There are different reasons given for wanting such a feature. One can debate whether the added complexity is worth the benefit, and in most cases it is not. However, one important case stands out — customers with very large 32-bit objects who are not ready or able to make the transition to 64-bits. We have customers who build extremely large 32-bit objects. Historically, the debug sections in these objects have used the stabs format, which is limited, but relatively compact. In recent years, the industry has transitioned to the powerful but verbose DWARF standard. In some cases, the size of these debug sections is large enough to push the total object file size past the fundamental 4GB limit for 32-bit ELF object files. The best, and ultimately only, solution to overly large objects is to transition to 64-bits. However, consider environments where: Hundreds of users may be executing the code on large shared systems. (32-bits use less memory and bus bandwidth, and on sparc runs just as fast as 64-bit code otherwise). Complex finely tuned code, where the original authors may no longer be available. Critical production code, that was expensive to qualify and bring online, and which is otherwise serving its intended purpose without issue. Users in these risk adverse and/or high scale categories have good reasons to push 32-bits objects to the limit before moving on. Ancillary objects offer these users a longer runway. Design The design of ancillary objects is intended to be simple, both to help human understanding when examining elfdump output, and to lower the bar for debuggers such as dbx to support them. The primary and ancillary objects have the same set of section headers, with the same names, in the same order (i.e. each section has the same index in both files). A single added section of type SHT_SUNW_ANCILLARY is added to both objects, containing information that allows a debugger to identify and validate both files relative to each other. Given one of these files, the ancillary section allows you to identify the other. Allocable sections go in the primary object, and non-allocable ones go into the ancillary object. A small set of non-allocable objects, notably the symbol table, are copied into both objects. As noted above, most sections are only written to one of the two objects, but both objects have the same section header array. The section header in the file that does not contain the section data is tagged with the SHF_SUNW_ABSENT section header flag to indicate its placeholder status. Compiler writers and others who produce objects can set the SUNW_SHF_PRIMARY section header flag to mark non-allocable sections that should go to the primary object rather than the ancillary. If you don't request an ancillary object, the Solaris ELF format is unchanged. Users who don't use ancillary objects do not pay for the feature. This is important, because they exist to serve a small subset of our users, and must not complicate the common case. If you do request an ancillary object, the runtime behavior of the primary object will be the same as that of a normal object. There is no added runtime cost. The primary and ancillary object together represent a logical single object. This is facilitated by the use of a single set of section headers. One can easily imagine a tool that can merge a primary and ancillary object into a single file, or the reverse. (Note that although this is an interesting intellectual exercise, we don't actually supply such a tool because there's little practical benefit above and beyond using ld to create the files). Among the benefits of this approach are: There is no need for per-file symbol tables to reflect the contents of each file. The same symbol table that would be produced for a standard object can be used. The section contents are identical in either case — there is no need to alter data to accommodate multiple files. It is very easy for a debugger to adapt to these new files, and the processing involved can be encapsulated in input/output routines. Most of the existing debugger implementation applies without modification. The limit of a 4GB 32-bit output object is now raised to 4GB of code, and 4GB of debug data. There is also the future possibility (not currently supported) to support multiple ancillary objects, each of which could contain up to 4GB of additional debug data. It must be noted however that the 32-bit DWARF debug format is itself inherently 32-bit limited, as it uses 32-bit offsets between debug sections, so the ability to employ multiple ancillary object files may not turn out to be useful. Using Ancillary Objects (From the Solaris Linker and Libraries Guide) By default, objects contain both allocable and non-allocable sections. Allocable sections are the sections that contain executable code and the data needed by that code at runtime. Non-allocable sections contain supplemental information that is not required to execute an object at runtime. These sections support the operation of debuggers and other observability tools. The non-allocable sections in an object are not loaded into memory at runtime by the operating system, and so, they have no impact on memory use or other aspects of runtime performance no matter their size. For convenience, both allocable and non-allocable sections are normally maintained in the same file. However, there are situations in which it can be useful to separate these sections. To reduce the size of objects in order to improve the speed at which they can be copied across wide area networks. To support fine grained debugging of highly optimized code requires considerable debug data. In modern systems, the debugging data can easily be larger than the code it describes. The size of a 32-bit object is limited to 4 Gbytes. In very large 32-bit objects, the debug data can cause this limit to be exceeded and prevent the creation of the object. To limit the exposure of internal implementation details. Traditionally, objects have been stripped of non-allocable sections in order to address these issues. Stripping is effective, but destroys data that might be needed later. The Solaris link-editor can instead write non-allocable sections to an ancillary object. This feature is enabled with the -z ancillary command line option. $ ld ... -z ancillary[=outfile] ...By default, the ancillary file is given the same name as the primary output object, with a .anc file extension. However, a different name can be provided by providing an outfile value to the -z ancillary option. When -z ancillary is specified, the link-editor performs the following actions. All allocable sections are written to the primary object. In addition, all non-allocable sections containing one or more input sections that have the SHF_SUNW_PRIMARY section header flag set are written to the primary object. All remaining non-allocable sections are written to the ancillary object. The following non-allocable sections are written to both the primary object and ancillary object. .shstrtab The section name string table. .symtab The full non-dynamic symbol table. .symtab_shndx The symbol table extended index section associated with .symtab. .strtab The non-dynamic string table associated with .symtab. .SUNW_ancillary Contains the information required to identify the primary and ancillary objects, and to identify the object being examined. The primary object and all ancillary objects contain the same array of sections headers. Each section has the same section index in every file. Although the primary and ancillary objects all define the same section headers, the data for most sections will be written to a single file as described above. If the data for a section is not present in a given file, the SHF_SUNW_ABSENT section header flag is set, and the sh_size field is 0. This organization makes it possible to acquire a full list of section headers, a complete symbol table, and a complete list of the primary and ancillary objects from either of the primary or ancillary objects. The following example illustrates the underlying implementation of ancillary objects. An ancillary object is created by adding the -z ancillary command line option to an otherwise normal compilation. The file utility shows that the result is an executable named a.out, and an associated ancillary object named a.out.anc. $ cat hello.c #include <stdio.h> int main(int argc, char **argv) { (void) printf("hello, world\n"); return (0); } $ cc -g -zancillary hello.c $ file a.out a.out.anc a.out: ELF 32-bit LSB executable 80386 Version 1 [FPU], dynamically linked, not stripped, ancillary object a.out.anc a.out.anc: ELF 32-bit LSB ancillary 80386 Version 1, primary object a.out $ ./a.out hello worldThe resulting primary object is an ordinary executable that can be executed in the usual manner. It is no different at runtime than an executable built without the use of ancillary objects, and then stripped of non-allocable content using the strip or mcs commands. As previously described, the primary object and ancillary objects contain the same section headers. To see how this works, it is helpful to use the elfdump utility to display these section headers and compare them. The following table shows the section header information for a selection of headers from the previous link-edit example. Index Section Name Type Primary Flags Ancillary Flags Primary Size Ancillary Size 13 .text PROGBITS ALLOC EXECINSTR ALLOC EXECINSTR SUNW_ABSENT 0x131 0 20 .data PROGBITS WRITE ALLOC WRITE ALLOC SUNW_ABSENT 0x4c 0 21 .symtab SYMTAB 0 0 0x450 0x450 22 .strtab STRTAB STRINGS STRINGS 0x1ad 0x1ad 24 .debug_info PROGBITS SUNW_ABSENT 0 0 0x1a7 28 .shstrtab STRTAB STRINGS STRINGS 0x118 0x118 29 .SUNW_ancillary SUNW_ancillary 0 0 0x30 0x30 The data for most sections is only present in one of the two files, and absent from the other file. The SHF_SUNW_ABSENT section header flag is set when the data is absent. The data for allocable sections needed at runtime are found in the primary object. The data for non-allocable sections used for debugging but not needed at runtime are placed in the ancillary file. A small set of non-allocable sections are fully present in both files. These are the .SUNW_ancillary section used to relate the primary and ancillary objects together, the section name string table .shstrtab, as well as the symbol table.symtab, and its associated string table .strtab. It is possible to strip the symbol table from the primary object. A debugger that encounters an object without a symbol table can use the .SUNW_ancillary section to locate the ancillary object, and access the symbol contained within. The primary object, and all associated ancillary objects, contain a .SUNW_ancillary section that allows all the objects to be identified and related together. $ elfdump -T SUNW_ancillary a.out a.out.anc a.out: Ancillary Section: .SUNW_ancillary index tag value [0] ANC_SUNW_CHECKSUM 0x8724 [1] ANC_SUNW_MEMBER 0x1 a.out [2] ANC_SUNW_CHECKSUM 0x8724 [3] ANC_SUNW_MEMBER 0x1a3 a.out.anc [4] ANC_SUNW_CHECKSUM 0xfbe2 [5] ANC_SUNW_NULL 0 a.out.anc: Ancillary Section: .SUNW_ancillary index tag value [0] ANC_SUNW_CHECKSUM 0xfbe2 [1] ANC_SUNW_MEMBER 0x1 a.out [2] ANC_SUNW_CHECKSUM 0x8724 [3] ANC_SUNW_MEMBER 0x1a3 a.out.anc [4] ANC_SUNW_CHECKSUM 0xfbe2 [5] ANC_SUNW_NULL 0 The ancillary sections for both objects contain the same number of elements, and are identical except for the first element. Each object, starting with the primary object, is introduced with a MEMBER element that gives the file name, followed by a CHECKSUM that identifies the object. In this example, the primary object is a.out, and has a checksum of 0x8724. The ancillary object is a.out.anc, and has a checksum of 0xfbe2. The first element in a .SUNW_ancillary section, preceding the MEMBER element for the primary object, is always a CHECKSUM element, containing the checksum for the file being examined. The presence of a .SUNW_ancillary section in an object indicates that the object has associated ancillary objects. The names of the primary and all associated ancillary objects can be obtained from the ancillary section from any one of the files. It is possible to determine which file is being examined from the larger set of files by comparing the first checksum value to the checksum of each member that follows. Debugger Access and Use of Ancillary Objects Debuggers and other observability tools must merge the information found in the primary and ancillary object files in order to build a complete view of the object. This is equivalent to processing the information from a single file. This merging is simplified by the primary object and ancillary objects containing the same section headers, and a single symbol table. The following steps can be used by a debugger to assemble the information contained in these files. Starting with the primary object, or any of the ancillary objects, locate the .SUNW_ancillary section. The presence of this section identifies the object as part of an ancillary group, contains information that can be used to obtain a complete list of the files and determine which of those files is the one currently being examined. Create a section header array in memory, using the section header array from the object being examined as an initial template. Open and read each file identified by the .SUNW_ancillary section in turn. For each file, fill in the in-memory section header array with the information for each section that does not have the SHF_SUNW_ABSENT flag set. The result will be a complete in-memory copy of the section headers with pointers to the data for all sections. Once this information has been acquired, the debugger can proceed as it would in the single file case, to access and control the running program. Note - The ELF definition of ancillary objects provides for a single primary object, and an arbitrary number of ancillary objects. At this time, the Oracle Solaris link-editor only produces a single ancillary object containing all non-allocable sections. This may change in the future. Debuggers and other observability tools should be written to handle the general case of multiple ancillary objects. ELF Implementation Details (From the Solaris Linker and Libraries Guide) To implement ancillary objects, it was necessary to extend the ELF format to add a new object type (ET_SUNW_ANCILLARY), a new section type (SHT_SUNW_ANCILLARY), and 2 new section header flags (SHF_SUNW_ABSENT, SHF_SUNW_PRIMARY). In this section, I will detail these changes, in the form of diffs to the Solaris Linker and Libraries manual. Part IV ELF Application Binary Interface Chapter 13: Object File Format Object File Format Edit Note: This existing section at the beginning of the chapter describes the ELF header. There's a table of object file types, which now includes the new ET_SUNW_ANCILLARY type. e_type Identifies the object file type, as listed in the following table. NameValueMeaning ET_NONE0No file type ET_REL1Relocatable file ET_EXEC2Executable file ET_DYN3Shared object file ET_CORE4Core file ET_LOSUNW0xfefeStart operating system specific range ET_SUNW_ANCILLARY0xfefeAncillary object file ET_HISUNW0xfefdEnd operating system specific range ET_LOPROC0xff00Start processor-specific range ET_HIPROC0xffffEnd processor-specific range Sections Edit Note: This overview section defines the section header structure, and provides a high level description of known sections. It was updated to define the new SHF_SUNW_ABSENT and SHF_SUNW_PRIMARY flags and the new SHT_SUNW_ANCILLARY section. ... sh_type Categorizes the section's contents and semantics. Section types and their descriptions are listed in Table 13-5. sh_flags Sections support 1-bit flags that describe miscellaneous attributes. Flag definitions are listed in Table 13-8. ... Table 13-5 ELF Section Types, sh_type NameValue . . . SHT_LOSUNW0x6fffffee SHT_SUNW_ancillary0x6fffffee . . . ... SHT_LOSUNW - SHT_HISUNW Values in this inclusive range are reserved for Oracle Solaris OS semantics. SHT_SUNW_ANCILLARY Present when a given object is part of a group of ancillary objects. Contains information required to identify all the files that make up the group. See Ancillary Section. ... Table 13-8 ELF Section Attribute Flags NameValue . . . SHF_MASKOS0x0ff00000 SHF_SUNW_NODISCARD0x00100000 SHF_SUNW_ABSENT0x00200000 SHF_SUNW_PRIMARY0x00400000 SHF_MASKPROC0xf0000000 . . . ... SHF_SUNW_ABSENT Indicates that the data for this section is not present in this file. When ancillary objects are created, the primary object and any ancillary objects, will all have the same section header array, to facilitate merging them to form a complete view of the object, and to allow them to use the same symbol tables. Each file contains a subset of the section data. The data for allocable sections is written to the primary object while the data for non-allocable sections is written to an ancillary file. The SHF_SUNW_ABSENT flag is used to indicate that the data for the section is not present in the object being examined. When the SHF_SUNW_ABSENT flag is set, the sh_size field of the section header must be 0. An application encountering an SHF_SUNW_ABSENT section can choose to ignore the section, or to search for the section data within one of the related ancillary files. SHF_SUNW_PRIMARY The default behavior when ancillary objects are created is to write all allocable sections to the primary object and all non-allocable sections to the ancillary objects. The SHF_SUNW_PRIMARY flag overrides this behavior. Any output section containing one more input section with the SHF_SUNW_PRIMARY flag set is written to the primary object without regard for its allocable status. ... Two members in the section header, sh_link, and sh_info, hold special information, depending on section type. Table 13-9 ELF sh_link and sh_info Interpretation sh_typesh_linksh_info . . . SHT_SUNW_ANCILLARY The section header index of the associated string table. 0 . . . Special Sections Edit Note: This section describes the sections used in Solaris ELF objects, using the types defined in the previous description of section types. It was updated to define the new .SUNW_ancillary (SHT_SUNW_ANCILLARY) section. Various sections hold program and control information. Sections in the following table are used by the system and have the indicated types and attributes. Table 13-10 ELF Special Sections NameTypeAttribute . . . .SUNW_ancillarySHT_SUNW_ancillaryNone . . . ... .SUNW_ancillary Present when a given object is part of a group of ancillary objects. Contains information required to identify all the files that make up the group. See Ancillary Section for details. ... Ancillary Section Edit Note: This new section provides the format reference describing the layout of a .SUNW_ancillary section and the meaning of the various tags. Note that these sections use the same tag/value concept used for dynamic and capabilities sections, and will be familiar to anyone used to working with ELF. In addition to the primary output object, the Solaris link-editor can produce one or more ancillary objects. Ancillary objects contain non-allocable sections that would normally be written to the primary object. When ancillary objects are produced, the primary object and all of the associated ancillary objects contain a SHT_SUNW_ancillary section, containing information that identifies these related objects. Given any one object from such a group, the ancillary section provides the information needed to identify and interpret the others. This section contains an array of the following structures. See sys/elf.h. typedef struct { Elf32_Word a_tag; union { Elf32_Word a_val; Elf32_Addr a_ptr; } a_un; } Elf32_Ancillary; typedef struct { Elf64_Xword a_tag; union { Elf64_Xword a_val; Elf64_Addr a_ptr; } a_un; } Elf64_Ancillary; For each object with this type, a_tag controls the interpretation of a_un. a_val These objects represent integer values with various interpretations. a_ptr These objects represent file offsets or addresses. The following ancillary tags exist. Table 13-NEW1 ELF Ancillary Array Tags NameValuea_un ANC_SUNW_NULL0Ignored ANC_SUNW_CHECKSUM1a_val ANC_SUNW_MEMBER2a_ptr ANC_SUNW_NULL Marks the end of the ancillary section. ANC_SUNW_CHECKSUM Provides the checksum for a file in the c_val element. When ANC_SUNW_CHECKSUM precedes the first instance of ANC_SUNW_MEMBER, it provides the checksum for the object from which the ancillary section is being read. When it follows an ANC_SUNW_MEMBER tag, it provides the checksum for that member. ANC_SUNW_MEMBER Specifies an object name. The a_ptr element contains the string table offset of a null-terminated string, that provides the file name. An ancillary section must always contain an ANC_SUNW_CHECKSUM before the first instance of ANC_SUNW_MEMBER, identifying the current object. Following that, there should be an ANC_SUNW_MEMBER for each object that makes up the complete set of objects. Each ANC_SUNW_MEMBER should be followed by an ANC_SUNW_CHECKSUM for that object. A typical ancillary section will therefore be structured as: TagMeaning ANC_SUNW_CHECKSUMChecksum of this object ANC_SUNW_MEMBERName of object #1 ANC_SUNW_CHECKSUMChecksum for object #1 . . . ANC_SUNW_MEMBERName of object N ANC_SUNW_CHECKSUMChecksum for object N ANC_SUNW_NULL An object can therefore identify itself by comparing the initial ANC_SUNW_CHECKSUM to each of the ones that follow, until it finds a match. Related Other Work The GNU developers have also encountered the need/desire to support separate debug information files, and use the solution detailed at http://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html. At the current time, the separate debug file is constructed by building the standard object first, and then copying the debug data out of it in a separate post processing step, Hence, it is limited to a total of 4GB of code and debug data, just as a single object file would be. They are aware of this, and I have seen online comments indicating that they may add direct support for generating these separate files to their link-editor. It is worth noting that the GNU objcopy utility is available on Solaris, and that the Studio dbx debugger is able to use these GNU style separate debug files even on Solaris. Although this is interesting in terms giving Linux users a familiar environment on Solaris, the 4GB limit means it is not an answer to the problem of very large 32-bit objects. We have also encountered issues with objcopy not understanding Solaris-specific ELF sections, when using this approach. The GNU community also has a current effort to adapt their DWARF debug sections in order to move them to separate files before passing the relocatable objects to the linker. The details of Project Fission can be found at http://gcc.gnu.org/wiki/DebugFission. The goal of this project appears to be to reduce the amount of data seen by the link-editor. The primary effort revolves around moving DWARF data to separate .dwo files so that the link-editor never encounters them. The details of modifying the DWARF data to be usable in this form are involved — please see the above URL for details.

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