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Topic: A character string that causes server error (Read 2451 times) |
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fiziwig
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A character string that causes server error
« on: Jun 13th, 2007, 6:15pm » |
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The character string consisting of the four characters:
double quote
percent sign
r (lower case)
double quote
anywhere in the submitted text causes the server to reply with the message:
Bad Request
Your browser sent a request that this server could not understand.
Apache/2.0.59 (Unix) mod_ssl/2.0.59 OpenSSL/0.9.8e Server at www.ocf.berkeley.edu Port 80
when the "Post" button is clicked.
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towr
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Re: A character string that causes server error
« Reply #1 on: Jun 14th, 2007, 1:56am » |
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Just the percent sign is enough to cause a problem at the moment.
And when I try to delete old PMs or posts, I get
Quote:Method Not Implemented
GET to /~wwu/cgi-bin/yabb/YaBB.cgi not supported.
Apache/2.0.59 (Unix) mod_ssl/2.0.59 OpenSSL/0.9.8e Server at www.ocf.berkeley.edu Port 80 |
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Grimbal
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Re: A character string that causes server error
« Reply #2 on: Jun 14th, 2007, 3:32am » |
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%20 works.
00 instead of 20 doesn't.
As I said, I suspect there is an URLDecode going on, and a °/o without a valid code either creates an exception or is refused as suspect.
There must be a new firewall somewhere.
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towr
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Re: A character string that causes server error
« Reply #3 on: Jun 21st, 2007, 9:58am » |
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The problem that caused the error when trying to delete posts has been fixed, so you can recommence hiding your mistakes 
They're still searching for the percent-sign problem though.
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towr
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Re: A character string that causes server error
« Reply #4 on: Jun 21st, 2007, 1:44pm » |
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And now we can also post % to our hearts content again.
[e]actually, there's still a few strings beginning with % that don't work (like with 00), but I doubt they'll be a problem.[/e]
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| « Last Edit: Jun 21st, 2007, 2:12pm by towr » |
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Grimbal
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Re: A character string that causes server error
« Reply #5 on: Jun 22nd, 2007, 5:19am » |
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%
wow!
I've never appreciated the simple pleasure of posting a % sign before.
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Sameer
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Re: A character string that causes server error
« Reply #6 on: Jun 22nd, 2007, 4:34pm » |
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on Jun 22nd, 2007, 5:19am, Grimbal wrote:%
wow!
I've never appreciated the simple pleasure of posting a % sign before. |
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Did you anticipate this appreciation?
I would have seen you try this flow
1) Put % in the typing box
2) Press "Post"
3) Be amazed that the post actually showed up
4) Press "Edit" to type in the appreciation of the simple pleasure you just experience
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"Obvious" is the most dangerous word in mathematics.
--Bell, Eric Temple
Proof is an idol before which the mathematician tortures himself.
Sir Arthur Eddington, quoted in Bridges to Infinity
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JiNbOtAk
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Re: A character string that causes server error
« Reply #7 on: Jul 4th, 2007, 3:00am » |
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on Jun 22nd, 2007, 4:34pm, Sameer wrote:
Did you anticipate this appreciation?
I would have seen you try this flow
1) Put % in the typing box
2) Press "Post"
3) Be amazed that the post actually showed up
4) Press "Edit" to type in the appreciation of the simple pleasure you just experience
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Hehe, Sameer, nice observation on Grimby's ESP prowess 
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denis
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Re: A character string that causes server error
« Reply #8 on: Jul 9th, 2007, 7:11pm » |
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I get the famous "Bad Request Your browser sent a request that this server could not understand " whenever I have the umlaut (the double dot) over a vowel like in naive (here I used only the single dot on the "i" just so it could post this).
I suspect letters with french accents might also be affected but haven't tried.
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| « Last Edit: Jul 10th, 2007, 12:59am by denis » |
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Grimbal
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Re: A character string that causes server error
« Reply #9 on: Jul 10th, 2007, 1:08am » |
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ï?
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Grimbal
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Re: A character string that causes server error
« Reply #10 on: Jul 10th, 2007, 1:42am » |
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The post above is the UTF-8 encoding of i-with-2-dots. The A-tilde alone (and all french accentuated characters I tested) are rejected.
One explanation I see is that there is a firewall that filters incoming requests and rejects anything suspicious. It assumes the post is UTF-8 and tries to decode it. If it cannot do that, it rejects the request.
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denis
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Re: A character string that causes server error
« Reply #11 on: Jul 10th, 2007, 6:59am » |
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Thanks for checking this Grimbal. I suspected as much.
My problem occurred when I was trying to put up my longest post (Framed!) so I thought it was the large size. But then I compared the size against the incredibly long riddle "Feux d'artifice" from Iceman. Mine had less text so I had to search out the problem by adding one paragraph at a time until I found the offending paragraph, then the offending sentence and then the offending word.
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| « Last Edit: Jul 10th, 2007, 7:03am by denis » |
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SMQ
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Re: A character string that causes server error
« Reply #12 on: Jul 12th, 2007, 12:10pm » |
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Percent may be working; ampersand ( ) seems to still cause errors. This can be a problem when posting code...
--SMQ
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--SMQ
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towr
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Re: A character string that causes server error
« Reply #13 on: Jul 12th, 2007, 12:28pm » |
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I seem to have no problems posting &
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towr
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Re: A character string that causes server error
« Reply #14 on: Jul 12th, 2007, 12:47pm » |
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(( seems to give a error, 501 "Method Not Implemented"
So that's different in nature than the 400 "bad request" the % gave. I cant' seem to find a lot of combinations with & that give a problem though.
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| « Last Edit: Jul 12th, 2007, 12:48pm by towr » |
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SMQ
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Re: A character string that causes server error
« Reply #15 on: Jul 12th, 2007, 12:48pm » |
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Hmm, this post of mine was throwing a server error until I replaced the & with its image. I'll try a few experiments.
Edit: the magic expression seems to be: /\([^0-9A-Za-z_]*&[^0-9A-Za-z_]*\(/ -- i.e. open-paren, optionally any string of entirely non-alphanumeric characters excluding underscore, ampersand, optionally any string of entirely non-alphanumeric characters excluding underscore, open-paren. Very odd.
--SMQ
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| « Last Edit: Jul 12th, 2007, 1:16pm by SMQ » |
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Sameer
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Re: A character string that causes server error
« Reply #16 on: Jul 12th, 2007, 1:16pm » |
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on Jul 12th, 2007, 12:47pm, towr wrote:(( seems to give a error, 501 "Method Not Implemented"
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er. the message seems scary.. looks like somebody could execute something on the server by passing appropriate string.. 
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"Obvious" is the most dangerous word in mathematics.
--Bell, Eric Temple
Proof is an idol before which the mathematician tortures himself.
Sir Arthur Eddington, quoted in Bridges to Infinity
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SMQ
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Re: A character string that causes server error
« Reply #17 on: Jul 12th, 2007, 1:20pm » |
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on Jul 12th, 2007, 1:16pm, Sameer wrote:
er. the message seems scary.. |
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Nah, it means "method" in the HTML sense, e.g. GET, POST, PUT, etc. It's just a very odd string to trigger a server error...
--SMQ
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towr
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Re: A character string that causes server error
« Reply #18 on: Jul 12th, 2007, 1:30pm » |
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The question is, is it something I ought to bother William or the OCF staff with?
We could throw in the umlauts as well..
I'm just always a bit hesitant when it's not really a huge problem. On the other hand, perhaps they'd rather know sooner than later.
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JiNbOtAk
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Re: A character string that causes server error
« Reply #19 on: Jul 12th, 2007, 6:31pm » |
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on Jul 12th, 2007, 1:30pm, towr wrote:| The question is, is it something I ought to bother William or the OCF staff with? |
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Of course we should tell them. It may be trivial, but I'm sure they'd want to know.
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