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

Dependents:   heating gps

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.

Committer:
andrewboyson
Date:
Wed Jul 31 15:09:15 2019 +0000
Revision:
127:bd6dd135009d
Parent:
112:f29bb9b99059
Child:
128:fc9708e1d17c
Amalgamated Reply into Poll function

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 109:3e82f62c7e1f 1
andrewboyson 109:3e82f62c7e1f 2 extern int WebInit(void);
andrewboyson 110:8ab752842d25 3
andrewboyson 110:8ab752842d25 4 #define DO_NOTHING 0
andrewboyson 110:8ab752842d25 5 #define DO_NOT_FOUND 1
andrewboyson 110:8ab752842d25 6 #define DO_NOT_MODIFIED 2
andrewboyson 110:8ab752842d25 7 #define DO_SERVER 10
andrewboyson 110:8ab752842d25 8 #define DO_BASE 100
andrewboyson 112:f29bb9b99059 9 #define DO_THIS 200
andrewboyson 110:8ab752842d25 10 #define DO_SEND_SESSION_ID 300