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/net/web-net6-ajax.c@127:bd6dd135009d, 2019-07-31 (annotated)

Committer:
andrewboyson
Date:
Wed Jul 31 15:09:15 2019 +0000
Revision:
127:bd6dd135009d
Parent:
110:8ab752842d25
Child:
142:b472ba95b018
Amalgamated Reply into Poll function

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 86:f3c9beec4ee7 1 #include <stdio.h>
andrewboyson 86:f3c9beec4ee7 2
andrewboyson 86:f3c9beec4ee7 3 #include "http.h"
andrewboyson 89:615fb951df69 4 #include "ndp.h"
andrewboyson 89:615fb951df69 5 #include "slaac.h"
andrewboyson 86:f3c9beec4ee7 6 #include "ar6.h"
andrewboyson 86:f3c9beec4ee7 7 #include "nr6.h"
andrewboyson 86:f3c9beec4ee7 8
andrewboyson 103:91194cc19bbb 9 void WebNet6Ajax()
andrewboyson 86:f3c9beec4ee7 10 {
andrewboyson 86:f3c9beec4ee7 11 HttpOk("text/plain; charset=UTF-8", "no-cache", NULL, NULL);
andrewboyson 89:615fb951df69 12
andrewboyson 89:615fb951df69 13 char nibble;
andrewboyson 89:615fb951df69 14 nibble = 0;
andrewboyson 89:615fb951df69 15 if (NdpManagedConfiguration) nibble |= 1; //4
andrewboyson 89:615fb951df69 16 if (NdpOtherConfiguration ) nibble |= 2; //4
andrewboyson 89:615fb951df69 17 if (NdpPrefixFlagL ) nibble |= 4; //4
andrewboyson 89:615fb951df69 18 if (NdpPrefixFlagA ) nibble |= 8; //4
andrewboyson 89:615fb951df69 19 HttpAddNibbleAsHex(nibble); HttpAddChar('\n');
andrewboyson 89:615fb951df69 20 HttpAddInt32AsHex(NdpHopLimit); HttpAddChar('\n');
andrewboyson 89:615fb951df69 21 for (char* p = NdpRouterMac; p < NdpRouterMac + 6; p++) HttpAddByteAsHex(*p); HttpAddChar('\n');
andrewboyson 89:615fb951df69 22 HttpAddInt32AsHex(NdpPrefixLength); HttpAddChar('\n');
andrewboyson 89:615fb951df69 23 HttpAddInt32AsHex(NdpPrefixValidLifetime); HttpAddChar('\n');
andrewboyson 89:615fb951df69 24 HttpAddInt32AsHex(NdpPrefixPreferredLifetime); HttpAddChar('\n');
andrewboyson 89:615fb951df69 25 for (char* p = NdpPrefix; p < NdpPrefix + 16; p++) HttpAddByteAsHex(*p); HttpAddChar('\n');
andrewboyson 89:615fb951df69 26 HttpAddInt32AsHex(NdpDnsLifetime); HttpAddChar('\n');
andrewboyson 89:615fb951df69 27 for (char* p = NdpDnsServer; p < NdpDnsServer + 16; p++) HttpAddByteAsHex(*p); HttpAddChar('\n');
andrewboyson 89:615fb951df69 28 HttpAddInt32AsHex(NdpGetLease()); HttpAddChar('\n');
andrewboyson 89:615fb951df69 29 HttpAddInt32AsHex(NdpGetElapsedLife()); HttpAddChar('\n');
andrewboyson 89:615fb951df69 30 for (char* p = SlaacLinkLocalIp; p < SlaacLinkLocalIp + 16; p++) HttpAddByteAsHex(*p); HttpAddChar('\n');
andrewboyson 89:615fb951df69 31 HttpAddInt32AsHex(NdpMtu); HttpAddChar('\n');
andrewboyson 89:615fb951df69 32 HttpAddChar('\f');
andrewboyson 89:615fb951df69 33
andrewboyson 88:2857259fc2b4 34 Ar6SendAjax();
andrewboyson 86:f3c9beec4ee7 35 HttpAddChar('\f');
andrewboyson 89:615fb951df69 36
andrewboyson 88:2857259fc2b4 37 Nr6SendAjax();
andrewboyson 86:f3c9beec4ee7 38 }