Harri,
On 4/19/24 08:10, Harri Pesonen wrote:
I have developed a restful web service, which uses HTTP response codes 200 OK,
201 Created, 204 No Content and 404 Not Found.
It does not use 400 Bad Request or 500 Internal Server Error normally.
400 Bad Request is more common than 500 Internal Server Error, which should
basically never happen.
I disagree. There aren't many good 5xx errors, so sometimes "500 Oops"
is the best you can do. HTTP 5xx doesn't even really allow you to
differentiate between "server error" and "application error".
400 Bad Request is the best response in many cases, if client gives some query
parameter which is not supported by the application logic.
-1
400 means that the HTTP request is bad. In your situation, the HTTP
request is 100% valid. It's your application that is saying "sorry,
client, you did something we don't allow". This is an application-level
error, not a protocol-level error. To me, 400 means "HTTP protocol
error" and should never be substituted for "application protocol error".
I think that it would be better not to close connection in this case, if the
error comes from application.
I wonder if there is option for application to define that connection should be
closed or not after the response has been sent?
Or is the option only from the client.
For me this 404 Not Found is also a small problem, as it is error, but it can
happen quite often.
HTTP errors are not nice in logs.
Normally if you try to fetch some restful resource, which does not exist, then
it returns 404 Not Found.
GET /service/resource/id => 404 Not Found
If I now had an option to rewrite the service, I would probably use 204 No
Content in this case as well, to avoid errors.
404 and 204 are fundamentally different responses. 404 means "this
resource does not exist" and 204 means "this resource DOES EXIST but it
doesn't contain anything". Your application may not differentiate
between those two cases, but as a client I would be confused if "Not
Found" was replaced by "Found to be empty" in all cases.
204 No Content is normally used with PUT and DELETE requests.
Yes, you can use those. 200 would also make sense and, of course 201 for
new resources.
-chris
-----Original Message-----
From: Christopher Schultz <ch...@christopherschultz.net>
Sent: perjantai 19. huhtikuuta 2024 14.27
To: users@tomcat.apache.org
Subject: Re: Tomcat closes connections on unexpected status codes
Mark,
On 4/18/24 11:38, Mark Thomas wrote:
On 18/04/2024 15:16, Adwait Kumar Singh wrote:
I think we should *always* close connections in cases where it can
lead to request smuggling vulnerabilities like when there is an error
during header or request line parsing, but allowing the user to
control connection close when the status is being set by the user,
should be safe?
I'm not (yet) convinced distinguishing between those scenarios is
always going to be possible.
It allows users to send back responses like InvalidInputException
with a
400 status without being forced to close the connection.
I appreciate why a 400 is used here but 400 has always struck me as
more for protocol level issues rather than application level issues.
Didn't someone tell me recently that, technically, ANY client-error is allowed
to trigger a 400 response without being more specific?
That is the fundamental problem here. The status codes are being used
for two completely different purposes.
+1
I've always found it distasteful when REST services do this. To me, 400 means "the request was
actually malformed". If you need authentication, that's a 401. If you aren't allowed, that's
403. If you didn't provide a required header, that's a 412, etc. I've usually found the
"correct"
response code to use for every situation and I've never written an application
that returns a 400 response directly.
-chris
On Thu, Apr 18, 2024 at 6:41 AM Rémy Maucherat <r...@apache.org> wrote:
On Thu, Apr 18, 2024 at 1:17 PM Mark Thomas <ma...@apache.org> wrote:
On 18/04/2024 09:07, Stefan Ansing wrote:
Hi,
We've observed some unexpected behaviour in Apache Tomcat (version
10.1.19)
where we see that HTTP/1.1 connections are closed whenever a
servlet application returns the following status codes: 400, 408,
411, 414,
500,
503, 501. This causes client applications to rapidly reconnect and
induce
high server-side CPU load due to doing TLS handshakes.
The 400 and 500 status codes are commonly used in RESTful
microservices to
communicate errors. Reviewing RFC 9112 I couldn't find any
requirement
for
closing connections on these status codes.
After testing with Undertow (version 2.3.12), where we didn't see
the
same
behaviour, we believe that these status codes do not necessitate a
new connection.
The Tomcat developers disagree. Connections are closed after these
status codes to avoid various forms of request smuggling attacks.
Checking the Tomcat sources makes me believe that the behaviour is
hard-coded[1]. I'm reaching out here to re-evaluate the list of
status codes and to discuss the possibilities of making the
behaviour
configurable.
Making this list of status codes configurable seems reasonable. The
default can stay as current and if users want to change it then
they have to accept the associated security risks.
If it's insecure, then it would still be a valid CVE even if the
configuration is optional. We don't have an "allowSmuggling"
attribute on the connector to relax header or status line parsing,
even though many would have wanted it in the past ...
Rémy
Mark
A colleague of mine reported a bug for this issue:
https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2F
bz.apache.org%2Fbugzilla%2Fshow_bug.cgi%3Fid%3D68901&data=05%7C02%
7Charri.pesonen%40sinch.com%7C66e83fa3469b43288fe608dc6063a357%7C3
b518aae89214a7b8497619d756ce20e%7C0%7C0%7C638491228268558870%7CUnk
nown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=l%2B6E%2BRgRxQmicXQ9ZOQpkIc
kaFzl70rI7O8ltNNvbSs%3D&reserved=0
Kind regards,
Stefan Ansing
[1]:
https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgi
thub.com%2Fapache%2Ftomcat%2Fblame%2Fbc900e0100de9879604b93af4722c27
2ab3d1a24%2Fjava%2Forg%2Fapache%2Fcoyote%2Fhttp11%2FHttp11Processor.
java%23L604-L617&data=05%7C02%7Charri.pesonen%40sinch.com%7C66e83fa3
469b43288fe608dc6063a357%7C3b518aae89214a7b8497619d756ce20e%7C0%7C0%
7C638491228268567937%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJ
QIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=fcgz%
2Bw473MyShaMac3v9yN%2BEnNfnX39x919bajNtC1U%3D&reserved=0
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