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.

Committer:
andrewboyson
Date:
Sat Apr 27 09:25:28 2019 +0000
Revision:
103:91194cc19bbb
Parent:
firmware/http-firmware-query.c@64:6660e41e2a7f
Renamed everything from Http to Web

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 47:cf7d4c34158e 1 #include "http.h"
andrewboyson 46:1822fdbe6c0c 2 #include "semihost.h"
andrewboyson 46:1822fdbe6c0c 3
andrewboyson 103:91194cc19bbb 4 void WebFirmwareQuery(char* pQuery)
andrewboyson 46:1822fdbe6c0c 5 {
andrewboyson 46:1822fdbe6c0c 6 while (pQuery)
andrewboyson 46:1822fdbe6c0c 7 {
andrewboyson 46:1822fdbe6c0c 8 char* pName;
andrewboyson 46:1822fdbe6c0c 9 char* pValue;
andrewboyson 46:1822fdbe6c0c 10 pQuery = HttpQuerySplit(pQuery, &pName, &pValue);
andrewboyson 63:daad0cbb4e8e 11 int value = HttpQueryValueAsInt(pValue);
andrewboyson 46:1822fdbe6c0c 12
andrewboyson 46:1822fdbe6c0c 13 if (HttpSameStr(pName, "restart" )) SemihostReset();
andrewboyson 46:1822fdbe6c0c 14 }
andrewboyson 46:1822fdbe6c0c 15 }