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

Dependents:   gps 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:
Tue Sep 24 18:16:47 2019 +0000
Revision:
130:9a5b8fe308f1
Parent:
128:fc9708e1d17c
Added http

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 110:8ab752842d25 1
andrewboyson 110:8ab752842d25 2 #define DO_NOTHING 0
andrewboyson 110:8ab752842d25 3 #define DO_NOT_FOUND 1
andrewboyson 110:8ab752842d25 4 #define DO_NOT_MODIFIED 2
andrewboyson 110:8ab752842d25 5 #define DO_SERVER 10
andrewboyson 110:8ab752842d25 6 #define DO_BASE 100
andrewboyson 112:f29bb9b99059 7 #define DO_THIS 200
andrewboyson 128:fc9708e1d17c 8 #define DO_SEND_SESSION_ID 300
andrewboyson 128:fc9708e1d17c 9
andrewboyson 130:9a5b8fe308f1 10 extern bool WebTrace;
andrewboyson 130:9a5b8fe308f1 11
andrewboyson 130:9a5b8fe308f1 12 extern void WebInit (void);
andrewboyson 130:9a5b8fe308f1 13
andrewboyson 130:9a5b8fe308f1 14 extern void WebAddResponse (int todo);
andrewboyson 130:9a5b8fe308f1 15 extern int WebHandleQuery (char* pQuery, char* pCookies, int* pTodo, uint32_t* pDelayUntil); //return -1 on stop; 0 on continue
andrewboyson 130:9a5b8fe308f1 16 extern void WebHandlePost (int todo, int contentLength, int contentStart, int size, char* pRequestStream, uint32_t positionInRequestStream, bool* pComplete);
andrewboyson 130:9a5b8fe308f1 17 extern int WebDecideWhatToDo(char *pPath, char* pLastModified);