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.

http/http.h

Committer:
andrewboyson
Date:
2021-05-11
Revision:
160:daa94b75b94c
Parent:
159:bda5b89e8c19

File content as of revision 160:daa94b75b94c:

#include <stdbool.h>
#include <stdarg.h>
#include <stdint.h>
#include <time.h>

#define HTTP_WAIT                    0
#define HTTP_FINISHED                1
#define HTTP_HAVE_SOMETHING_TO_SEND  2

extern void   HttpReset   (int connectionId);
extern bool   HttpAdd     (int connectionId,                      int* pWindowSize, char* pWindow, uint32_t windowPositionInStream); //returns true if finished; false if not
extern int    HttpPoll    (int connectionId, bool clientFinished);  //returns true if something to send; false if not
extern void   HttpRequest (int connectionId,                      int   windowSize, char* pWindow, uint32_t windowPositionInStream);

extern bool   HttpGetTrace(void);

extern void   HttpAddStart        (uint32_t position, int mss, char *pData);
extern int    HttpAddLength       (void);
extern bool   HttpAddFilled       (void);

extern void   HttpAddChar         (char c);
extern void   HttpAddFillChar     (char c, int length);
extern int    HttpAddText         (const char* text);
extern int    HttpAddTextN        (const char* text, int length);
extern int    HttpAddV            (char *fmt, va_list argptr);
extern int    HttpAddF            (char *fmt, ...);
extern void   HttpAddData         (const char* data, int length);
extern void   HttpAddStream       (void (*startFunction)(void), int (*enumerateFunction)(void));
extern void   HttpAddNibbleAsHex  (int value);
extern void   HttpAddByteAsHex    (int value);
extern void   HttpAddInt12AsHex   (int value);
extern void   HttpAddInt16AsHex   (int value);
extern void   HttpAddInt32AsHex   (int value);
extern void   HttpAddInt64AsHex   (int64_t value);
extern void   HttpAddBytesAsHex   (const uint8_t* value, int size);
extern void   HttpAddBytesAsHexRev(const uint8_t* value, int size);
extern void   HttpAddTm           (struct tm* ptm);

extern void   HttpOk(const char* contentType, const char* cacheControl, const char* lastModifiedDate, const char* lastModifiedTime);
extern char*  HttpOkCookieName;
extern char*  HttpOkCookieValue;
extern int    HttpOkCookieMaxAge;

extern void   HttpNotFound        (void);
extern void   HttpNotModified     (void);

extern int    HttpRequestRead(char *p, int len, char** ppMethod, char** ppPath, char** ppQuery, char** ppLastModified, char** ppCookies, int* pContentLength);

extern char*  HttpCookiesSplit      (char* pCookies, char** ppName, char** ppValue);
extern char*  HttpQuerySplit        (char* pQuery,   char** ppName, char** ppValue);
extern int    HttpQueryValueAsInt   (char* pValue);
extern double HttpQueryValueAsDouble(char* pValue);
extern void   HttpQueryUnencode     (char* pValue);

extern void   HttpDateFromDateTime(const char* date, const char *ptime, char* ptext);
extern void   HttpDateFromNow(char* pText);

extern bool HttpSameStr               (const char* pa,   const char* pb);
extern bool HttpSameStrCaseInsensitive(const char* pa,   const char* pb);
extern bool HttpSameDate              (const char* date, const char* time, const char* pOtherDate);

#define HTTP_DATE_LENGTH 30