Debugging Tricks with Apache HTTP Server 2.4 PDF

Apache webserver runs as a specific user (www-data) and handles all HTTP requests for all websites. Apache needs to be able to read the files on each

Apache Byte Range Requests

Apache HTTP Server byte-range filter The vulnerability occurs during the handling of requests that declare a. Do you can make use terms of bytes

A Comprehensive Approach to Abusing Locality in Shared Web

Webserver runs as a specific user account (apache daemon

Writing Apache modules in Free Pascal

1 avr. 2007 mechanism could for instance be set up to handle HTTP authentication with a non-standard ... When processing a request

Apache ShenYu document

2 juil. 2022 Apache ShenYu gateway the HTTP request is handled by the Divide plugin. If you are a startup gateway by means of source

Debugging Tricks with Apache HTTP Server 2.4

7 avr. 2014 This logs the start and end of the request along with all of the request headers. +UJggYn8AAQEAAAs1da4AAAAA

httpclient-tutorial.pdf

involves one or several HTTP request / HTTP response exchanges usually handled internally by. HttpClient. The user is expected to provide a request object

Apache Wink Developer Guide 1.0

15 oct. 2009 URL Handling. The Apache Wink receives HTTP requests and then dispatches a wrapped HTTP request to the appropriate. Resource method.

httpcore-tutorial.pdf

HTTP request is a message sent from the client to the server. HttpService is a server side HTTP protocol handler based on the blocking I/O model that ...

Apache::* modules

15 févr. 2014 Apache handlers which handle request phases or whole requests and are ... 1.2 Apache::Session - Maintain session state across HTTP requests.

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingDebugging Tricks with Apache HTTP Server 2.4

Je Trawick

http://emptyhammock.com/ trawick@emptyhammock.com

April 7, 2014

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingGet these slides...

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingTable of Contents

1Introduction2What kinds of issues encountered3Using tools to look inside the web server4Looking from the outside5What if you build the code dierently6Compare with httpd 2.27References and further reading

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingIntroduction | Who am I?

I've worked at

several large corporations, for over two decades my own one-personcompany, Emptyhammock, for the last two yearsI've worked on several products which were primarily based on or otherwise included Apache HTTP Serverlower-level networking products web applications I've debuggedmanycustomer and user problems over the years.

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingIntroduction | What will we attempt to cover?

Touch on all the basics.

Describe all the new httpd 2.4 debugging features. Summarize the techniques which are dierent with httpd 2.2.

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingWhat kinds of issues encountered Crash

Hang of server

Stall of individual requests

Termination

Bad response time

Limited concurrency

without problem symptomsHigh CPU

High memory

High consumption of other

pooled resourcesIncorrect output - wrong transformationIncorrect output - missing/bad protocol element

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingNon-problems

Validate behavior of new software/conguration

Understand steady-state behavior for baseline when something is wrong

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingUsing tools to look inside the web server Logging (the information itself, the timestamp, information

about other processing at about the same time)OS-level tools (view use of resources, whether discrete

items like les or continuous like CPU)CPU-, code-level tools (determine what code is running frequently, what is running for the request, analyze memory references, walk through the processing of a request, etc.)

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingCareful with logging! As you increase the level of logging, you increase the chances that private data will be logged.Passwords, session keys, etc. Modules/log congurations of particular interest:moddumpio, modlogcong when congured to log certain request or response header eldsmodlogforensic http (the built-in module) when congured at higher trace levels

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingLogging

Error log

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further readingError log records

Congurable content

Fields dropped when information is unavailable

Third-party modules can implement their own elds

Typical message:

[Sun Oct 28 13:37:27.676386 2012] [:error] [pid 14340:tid 140625844377344] [client 127.0.0.1:50837] mod_wsgi (pid=14340): Target WSGI script /home/trawick/myhg/apache/documents/AC20

12EU/lookup.wsgi

does not contain WSGI application application

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

look inside the web server

Looking from

the outside

What if you

build the code dierently

Compare with

httpd 2.2

References

and further

readingHiding error log eldsThe ErrorLogFormat directive can limit which elds are logged, but you could implement post-processing

to remove elds as appropriate for what you are debugging.

My own silly mechanism:

$ grep Accept-Ranges logs/error_log

[Thu Apr 03 07:26:49.605322 2014] [http:trace4] [pid 13680:tid 140130244732672] http_filters.c(837): [client 192.168.1.207:60141] Accept-Ranges: bytes

$ grep Accept-Ranges logs/error_log | nots.pl

[http:trace4] [pid 13680:tid 140130244732672] http_filters.c(837): [client 192.168.1.207:60141] Accept-Ranges: bytes

$ grep Accept-Ranges logs/error_log | nots.pl | nomodlevel.pl

[pid 13680:tid 140130244732672] http_filters.c(837): [client 192.168.1.207:60141] Accept-Ranges: bytes

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

issues encountered

Using tools to

quotesdbs_dbs20.pdfusesText_26

[PDF] Debugging Tricks with Apache HTTP Server 2.4

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

Using tools to

Looking from

What if you

Compare with

References

Je Trawick

April 7, 2014

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

Using tools to

Looking from

What if you

Compare with

References

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

Using tools to

Looking from

What if you

Compare with

References

1Introduction2What kinds of issues encountered3Using tools to look inside the web server4Looking from the outside5What if you build the code dierently6Compare with httpd 2.27References and further reading

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

Using tools to

Looking from

What if you

Compare with

References

I've worked at

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

Using tools to

Looking from

What if you

Compare with

References

Touch on all the basics.

Debugging

Tricks with

Apache HTTP

Server 2.4

Je Trawick

Introduction

What kinds of

Using tools to

Looking from

What if you

Compare with

References

Hang of server

Stall of individual requests