Andrew Boyson / web

Common stuff for all my devices' web server pages: css, login, log, ipv4, ipv6, firmware update, clock, reset info etc.

Dependents:   oldheating gps motorhome heating

Security

A password has to be set whenever there has been a software reset. Resets following faults or power on do not require a new password as the hash is restored from the RTC GPREG register.

The password is not saved on the device; instead a 32 bit hash of the password is saved. It would take 2^31 attempts to brute force the password: this could be done in under a month if an attempt were possible every millisecond. To prevent this a 200 ms delay is introduced in the reply to the login form, that gives a more reasonable 13 years to brute force the password.

Once the password is accepted a random session id is created. This is 36 bit to give six base 64 characters but without an extra delay. If an attempt could be made every ms then this would still take over a year to brute force.

The most likely attack would to use a dictionary with, say, 10 million entries against the password which would still take 20 days to do.

http/http-connection.h@130:9a5b8fe308f1, 2019-09-24 (annotated)

Committer:
andrewboyson
Date:
Tue Sep 24 18:16:47 2019 +0000
Revision:
130:9a5b8fe308f1
Parent:
web-connection.h@128:fc9708e1d17c 
Added http

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 128:fc9708e1d17c 1 #include <stdint.h>
andrewboyson 128:fc9708e1d17c 2 #include <stdbool.h>
andrewboyson 128:fc9708e1d17c 3
andrewboyson 130:9a5b8fe308f1 4 struct HttpConnection
andrewboyson 128:fc9708e1d17c 5 {
andrewboyson 128:fc9708e1d17c 6 int id; //An id of zero means the record is empty
andrewboyson 128:fc9708e1d17c 7 uint32_t lastUsed;
andrewboyson 128:fc9708e1d17c 8 int toDo;
andrewboyson 128:fc9708e1d17c 9 bool postComplete;
andrewboyson 128:fc9708e1d17c 10 uint32_t delayUntil;
andrewboyson 128:fc9708e1d17c 11 };
andrewboyson 128:fc9708e1d17c 12
andrewboyson 130:9a5b8fe308f1 13 extern struct HttpConnection* HttpConnectionNew (int connectionId); //Never fails so never returns NULL
andrewboyson 130:9a5b8fe308f1 14 extern struct HttpConnection* HttpConnectionOrNull(int connectionId);
andrewboyson 130:9a5b8fe308f1 15 extern void HttpConnectionReset (int connectionId);