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#ls2
/2022/08/23
@eyedeekay
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+orignal
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orignal I will check if there is a problem
orignal <html><body>You are being <a href="http://git.idk.i2p/users/sign_in">redirected</a>.</body></html
orignal and this link doesn't respond
orignal hanging forever
R4SAS pulling i2p packages to my repo
orignal eyedeekay the issue has been identified
orignal git.idk.i2p sends giant HTTP header
orignal and we did't merge them prorerly
orignal the fix is comming in i2pd
orignal but please check why you do it
eyedeekay I'll have a look, if there's anything I can do on my end I will make it happen
eyedeekay Likely that enormous CSP header
zzz how big?
R4SAS all google stuff listed
zzz ok, just saw it with firefox inspect
zzz about 1053 chars FYI
R4SAS on issues page with autentification?
zzz here's the whole thing:
zzz Content-Security-Policy
zzz d i2pgit.org/assets blob: data:; connect-src 'self' ws://i2pgit.org cdn.co…gleapis.com content-cloudresourcemanager.googleapis.com; img-src * data: blob: *.google-analytics.com *.googletagmanager.com; manifest-src 'self'; media-src 'self' data:; object-src 'none'; script-src 'self' 'unsafe-inline' 'unsafe-eval' recaptcha.net apis.google.com cdn.cookielaw.or
zzz g *.onetrust.com cdn.bizible.com/scripts/bizible.js *.googletagmanager.com 'nonce-/R7rvSnQ6HY+U2F50/7dGw=='; style-src 'self' 'unsafe-inline'; worker-src 'self' 'unsafe-inline'
R4SAS orignal talk about whole header
R4SAS with Connection, Permissions, etc, etc
zzz most of that is crap for the in-net site anyway
dr|z3d there's probably a setting you can bump to increase the max header size.
zzz setting for what?
dr|z3d max size of header.
zzz or else what? truncate?
dr|z3d or else fail. at least in nginx.
zzz there is no max size in the standard iirc, just best practices
R4SAS dr|z3d: problem on our http proxy side
dr|z3d that's as may be, but the webserver usually has a hard limit you need to increase for heavy headers.
zzz the old school rfc that allowed headers to be split and glued back together is deprecated because it's such a security mess
R4SAS which can't handle such long header
zzz let me see what our max is
dr|z3d R4SAS: if nginx, could be you need to check proxy_headers_hash_max_size
R4SAS dr|z3d: huh?
R4SAS we connecting to git.idk.i2p
R4SAS wgy are you talking about nginx?
dr|z3d if nginx is handling the proxying..
dr|z3d otherwise, nevermind.
R4SAS why*
dr|z3d nginx can do many things, I thought you might be using nginx to reverse proxy.
R4SAS idk what eyedeekay uses as reverse proxy
eyedeekay It's nginx
dr|z3d eyedeekay: if nginx, could be you need to check proxy_headers_hash_max_size :)
dr|z3d there may be other related settings you can tweak, depends how you're handling things, but it sounds like you need to increase the header buffers one way or another.
R4SAS he can just cut whole CSP header with google stuff
zzz ok, research done:
dr|z3d yeah, the google stuff can be removed, but that's probably doing stats or something.
dr|z3d (all the more reason for it to be dropped)
zzz orignal, R4SAS - what we do:
zzz Blinded message
zzz if that's exceeded:
zzz Blinded message
zzz we also have a total size limit for all headers:
zzz Blinded message
dr|z3d except it's probably the _response_ headers that are too large, not the _request_ headers.
dr|z3d minor thing.
zzz correction:
zzz Blinded message
zzz we also return a 431 for that
zzz we also have a check for the request line being too long
zzz that's the same 8K limit
zzz but the error return for that is:
zzz Blinded message
dr|z3d ok, so basically i2pd needs more generous buffers for the headers; java i2p does fine as is. that seems to be the issue, in summary :)
zzz tl;dr your limits can be whatever is reasonable, but return an error code if exceeded
dr|z3d and what zzz said.
zzz "more generous" is not sufficient.
R4SAS orignal added reading continuation
zzz you have to make sure you don't let an attacker do line splitting and getting split headers through
zzz or OOM or crash or buffer overflow
dr|z3d Not seen anything on the reponse header front requiring more than 128KB, if that helps.
dr|z3d I may have seen something pushing ~60KB headers recently.
zzz you can't let somebody send you a 100 MB header line
dr|z3d KB, not MB.
dr|z3d lol @ 100MB.
zzz or a million 100-byte header lines
zzz or a 100 MB request line
dr|z3d absolutely not, I agree.
orignal zzz, it's around 3800 bytes
R4SAS orignal: ping )))
orignal just headr
dr|z3d what I was driving at is that 128KB is probably about as generous as you need to be.
orignal zzz first header was like 1800 but after redirect second one was 3800
orignal it's fixed alreadt
dr|z3d 3.8K is nothing special, anyways.
orignal just never met the siatusation when header is bigger then one streaming packet
orignal ofc, just never saw it before
orignal zzz, good point but OOM
orignal just 128K max. right?
dr|z3d yeah, if you want a hard limit that should never be exhausted.
orignal no prolem for me
orignal to implement this check
dr|z3d unlikely you'll see anything near that, but as I mentioned, I've seen ~60K headers before.
R4SAS do we really need 60K header in i2p?
dr|z3d not really needed anywhere, but that doesn't stop people :)
dr|z3d java i2p strips a few unneeded headers which may or may not help keep things sane.
R4SAS eyedeekay: didn't know why, but related_branches always returns 404
dr|z3d X-Powered-By and junk like that.
zzz I don't remember where I got the 8K per-header limit but I believed that I researched chrome/firefox/microsoft
orignal an attacker can make a signle like bery long
zzz right, the main point is that crashes, request splitting/smuggling, and memory corruption may all be possible if it isn't done right, and the attack vector is super-easy
dr|z3d that's 2017, but still, that suggests an 8K limit
orignal why can we limit to 8K?
dr|z3d > One is likely to run into these limits when using cookies to track some attribute of a visitor that has no upper limit. For example, imagine an e-commerce application stored the contents of a visitors shopping cart in a cookie. This would be problematic, as, when a user’s shopping cart exceeds some certain amount, the size Set-Cookie header containing the contents of the cart would exceed the HTTP respons
dr|z3d e header size limit.
dr|z3d pick a value, see if it causes issues, make 128K is too generous.
dr|z3d *maybe
zzz orignal, pick whatever limit you want, the important thing is to handle it correctly and return an error if exceeded
zzz for each of three limits: request line length, header line length, total header size
orignal why should I reuurn error rather than just close the socket?
zzz that's the standard
zzz also, possibly a 4th limit: total number of header lines
zzz Blinded message
zzz Blinded message
zzz and it also would have made debugging the problem a lot easier :)
R4SAS someone who wrote this manual are crazy
zzz Author: idk
R4SAS about third part with creating tunnel for SSH
orignal I guessed so ))
eyedeekay it works, I guess SOCKS would work too, and http_proxy works for cloning via HTTP
R4SAS eyedeekay: ~/.ssh/config
zzz you said 3800 bytes but according to firefox the headers total 2109 bytes for git.idk.i2p/users/sign_in - but it depends where you look I guess because there's internal i2p headers
R4SAS a smmaaaaaaaalll hint for you
zzz eyedeekay, I questioned doing SSH at the time instead of just HTTP, but I think it was the right call to separate SSH and not really even support/advertise HTTP
zzz better to keep the traffic on different tunnels, for throttling, etc.
orignal I saw when printed out what we received
orignal the proint is it exceeds one streaming packet size
orignal so it doesn't matter 2100 or 3800
orignal the result is the same
zzz sure
eyedeekay I leave it enabled so that other instances inside I2P can import code from us using the http clone URL, otherwise SSH is the normal thing on i2pgit
zzz no matter what's hammering the website or whatever rewriting shenanigans might be broken, SSH has been super solid
zzz definitely was the right way to go
eyedeekay Yeah if I had it to do over again I might have fought harder for gitea, gitlab's ongoing issue has been keeping up with CSP and in general it's absolutely behemoth size
eyedeekay But it's really good at a ton of other stuff and moving would be a mess so I'm just going to keep up with it
eyedeekay gitlab's got this ongoing project to fix all the CSP issues it can have which makes everything a moving target
R4SAS yes... same thing about gitlab's size and it's CPU/MEM usage
R4SAS that's why I moved to gitea
eyedeekay Yeah it's quite big. gitea is much easier to manage for the most part, but a whole other migration and all that goes into that just isn't something I have time to oversee right now
dr|z3d yeah, gitea is like butter compared to gitlab. much less taxing on the cpu as well.
zzz I guess it was all the tor trac migration scripts that clinched it for gitlab
dr|z3d and gitea has a handy mirror feature which gitlab appears to lack.
zzz anyway, congrats to the i2pd team for chasing down a nasty bug :)
dr|z3d chocolate potatoes all round!
dr|z3d it's a delicacy in Russia, apparently.