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.

net/web-net6-ajax.c@103:91194cc19bbb, 2019-04-27 (annotated)

Committer:
andrewboyson
Date:
Sat Apr 27 09:25:28 2019 +0000
Revision:
103:91194cc19bbb
Parent:
net/http-net6-ajax.c@89:615fb951df69 
Renamed everything from Http to Web

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 103:91194cc19bbb 4 #include "web-base.h"
andrewboyson 89:615fb951df69 5 #include "ndp.h"
andrewboyson 89:615fb951df69 6 #include "slaac.h"
andrewboyson 86:f3c9beec4ee7 7 #include "ar6.h"
andrewboyson 86:f3c9beec4ee7 8 #include "nr6.h"
andrewboyson 86:f3c9beec4ee7 9
andrewboyson 103:91194cc19bbb 10 void WebNet6Ajax()
andrewboyson 86:f3c9beec4ee7 11 {
andrewboyson 86:f3c9beec4ee7 12 HttpOk("text/plain; charset=UTF-8", "no-cache", NULL, NULL);
andrewboyson 89:615fb951df69 13
andrewboyson 89:615fb951df69 14 char nibble;
andrewboyson 89:615fb951df69 15 nibble = 0;
andrewboyson 89:615fb951df69 16 if (NdpManagedConfiguration) nibble |= 1; //4
andrewboyson 89:615fb951df69 17 if (NdpOtherConfiguration ) nibble |= 2; //4
andrewboyson 89:615fb951df69 18 if (NdpPrefixFlagL ) nibble |= 4; //4
andrewboyson 89:615fb951df69 19 if (NdpPrefixFlagA ) nibble |= 8; //4
andrewboyson 89:615fb951df69 20 HttpAddNibbleAsHex(nibble); HttpAddChar('\n');
andrewboyson 89:615fb951df69 21 HttpAddInt32AsHex(NdpHopLimit); HttpAddChar('\n');
andrewboyson 89:615fb951df69 22 for (char* p = NdpRouterMac; p < NdpRouterMac + 6; p++) HttpAddByteAsHex(*p); HttpAddChar('\n');
andrewboyson 89:615fb951df69 23 HttpAddInt32AsHex(NdpPrefixLength); HttpAddChar('\n');
andrewboyson 89:615fb951df69 24 HttpAddInt32AsHex(NdpPrefixValidLifetime); HttpAddChar('\n');
andrewboyson 89:615fb951df69 25 HttpAddInt32AsHex(NdpPrefixPreferredLifetime); HttpAddChar('\n');
andrewboyson 89:615fb951df69 26 for (char* p = NdpPrefix; p < NdpPrefix + 16; p++) HttpAddByteAsHex(*p); HttpAddChar('\n');
andrewboyson 89:615fb951df69 27 HttpAddInt32AsHex(NdpDnsLifetime); HttpAddChar('\n');
andrewboyson 89:615fb951df69 28 for (char* p = NdpDnsServer; p < NdpDnsServer + 16; p++) HttpAddByteAsHex(*p); HttpAddChar('\n');
andrewboyson 89:615fb951df69 29 HttpAddInt32AsHex(NdpGetLease()); HttpAddChar('\n');
andrewboyson 89:615fb951df69 30 HttpAddInt32AsHex(NdpGetElapsedLife()); HttpAddChar('\n');
andrewboyson 89:615fb951df69 31 for (char* p = SlaacLinkLocalIp; p < SlaacLinkLocalIp + 16; p++) HttpAddByteAsHex(*p); HttpAddChar('\n');
andrewboyson 89:615fb951df69 32 HttpAddInt32AsHex(NdpMtu); HttpAddChar('\n');
andrewboyson 89:615fb951df69 33 HttpAddChar('\f');
andrewboyson 89:615fb951df69 34
andrewboyson 88:2857259fc2b4 35 Ar6SendAjax();
andrewboyson 86:f3c9beec4ee7 36 HttpAddChar('\f');
andrewboyson 89:615fb951df69 37
andrewboyson 88:2857259fc2b4 38 Nr6SendAjax();
andrewboyson 86:f3c9beec4ee7 39 }