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.

base/favicon/web-favicon.c@127:bd6dd135009d, 2019-07-31 (annotated)

Committer:
andrewboyson
Date:
Wed Jul 31 15:09:15 2019 +0000
Revision:
127:bd6dd135009d
Parent:
110:8ab752842d25 
Amalgamated Reply into Poll function

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 103:91194cc19bbb 1 #include "http.h"
andrewboyson 103:91194cc19bbb 2
andrewboyson 103:91194cc19bbb 3 //Use http://tomeko.net/online_tools/file_to_hex.php to convert a favicon.ico into hex readable as an array
andrewboyson 103:91194cc19bbb 4 static const char bytes[] = {
andrewboyson 103:91194cc19bbb 5 #include "favicon/web-favicon.inc"
andrewboyson 103:91194cc19bbb 6 };
andrewboyson 103:91194cc19bbb 7
andrewboyson 103:91194cc19bbb 8 const char* WebFaviconDate = __DATE__;
andrewboyson 103:91194cc19bbb 9 const char* WebFaviconTime = __TIME__;
andrewboyson 103:91194cc19bbb 10 const int WebFaviconSize = sizeof(bytes);
andrewboyson 103:91194cc19bbb 11
andrewboyson 103:91194cc19bbb 12 void WebFavicon()
andrewboyson 103:91194cc19bbb 13 {
andrewboyson 103:91194cc19bbb 14 HttpOk("image/x-icon", "max-age=3600", WebFaviconDate, WebFaviconTime);
andrewboyson 103:91194cc19bbb 15 HttpAddData(bytes, WebFaviconSize);
andrewboyson 103:91194cc19bbb 16 }