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tcp/http/httprequest.c@117:a725e5ad4fad, 2019-01-26 (annotated)

Committer:
andrewboyson
Date:
Sat Jan 26 15:44:59 2019 +0000
Revision:
117:a725e5ad4fad
Parent:
110:67c96c143c2a
Child:
118:067cb5bce7e3
Found bug in function which retrieves the 'If-Last-Modified' line: the lastModified pointer is not initialised so could point anywhere if no line. Although checked for NULL it is not checked for other random values. Initialised to NULL.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 61:aad055f1b0d1 1 #include <stdbool.h>
andrewboyson 61:aad055f1b0d1 2 #include <stdio.h>
andrewboyson 61:aad055f1b0d1 3 #include <string.h>
andrewboyson 54:84ef2b29cf7e 4
andrewboyson 110:67c96c143c2a 5 #include "http.h"
andrewboyson 110:67c96c143c2a 6
andrewboyson 110:67c96c143c2a 7 static char* terminateThisAndGetNextLine(char* p, char* pE) //Terminates this line and returns the start of the next line or NULL if none
andrewboyson 54:84ef2b29cf7e 8 {
andrewboyson 54:84ef2b29cf7e 9 while (true)
andrewboyson 54:84ef2b29cf7e 10 {
andrewboyson 110:67c96c143c2a 11 if ( p == pE) { *p = 0; return NULL; } //No more buffer - relies on having designed the buffer to be bigger than an ethernet packet
andrewboyson 110:67c96c143c2a 12 if (*p == 0) return NULL; //There are no more lines
andrewboyson 110:67c96c143c2a 13 if (*p == '\n') { *p = 0; return p + 1; } //return the start of the next line
andrewboyson 110:67c96c143c2a 14 if (*p < ' ') { *p = 0; return NULL; } //Invalid characters
andrewboyson 110:67c96c143c2a 15 if (*p >= 0x7f) { *p = 0; return NULL; } //Invalid characters
andrewboyson 54:84ef2b29cf7e 16 p++;
andrewboyson 54:84ef2b29cf7e 17 }
andrewboyson 54:84ef2b29cf7e 18 }
andrewboyson 54:84ef2b29cf7e 19
andrewboyson 110:67c96c143c2a 20 static void splitRequest(char* p, char** ppMethod, char** ppPath, char** ppQuery)
andrewboyson 54:84ef2b29cf7e 21 {
andrewboyson 54:84ef2b29cf7e 22 *ppMethod = NULL;
andrewboyson 54:84ef2b29cf7e 23 *ppPath = NULL;
andrewboyson 54:84ef2b29cf7e 24 *ppQuery = NULL;
andrewboyson 54:84ef2b29cf7e 25
andrewboyson 54:84ef2b29cf7e 26 while (*p == ' ') //Move past any leading spaces
andrewboyson 54:84ef2b29cf7e 27 {
andrewboyson 54:84ef2b29cf7e 28 if (*p == 0) return;
andrewboyson 54:84ef2b29cf7e 29 p++;
andrewboyson 54:84ef2b29cf7e 30 }
andrewboyson 54:84ef2b29cf7e 31 *ppMethod = p; //Record the start of the method (GET or POST)
andrewboyson 54:84ef2b29cf7e 32
andrewboyson 54:84ef2b29cf7e 33 while (*p != ' ') //Move past the method
andrewboyson 54:84ef2b29cf7e 34 {
andrewboyson 54:84ef2b29cf7e 35 if (*p == 0) return;
andrewboyson 54:84ef2b29cf7e 36 p++;
andrewboyson 54:84ef2b29cf7e 37 }
andrewboyson 54:84ef2b29cf7e 38 *p = 0; //Terminate the method
andrewboyson 54:84ef2b29cf7e 39 p++; //Start at next character
andrewboyson 54:84ef2b29cf7e 40
andrewboyson 54:84ef2b29cf7e 41 while (*p == ' ') //Move past any spaces
andrewboyson 54:84ef2b29cf7e 42 {
andrewboyson 54:84ef2b29cf7e 43 if (*p == 0) return;
andrewboyson 54:84ef2b29cf7e 44 p++;
andrewboyson 54:84ef2b29cf7e 45 }
andrewboyson 54:84ef2b29cf7e 46 *ppPath = p; //Record the start of the path
andrewboyson 54:84ef2b29cf7e 47
andrewboyson 54:84ef2b29cf7e 48 while (*p != ' ') //Move past the path and query
andrewboyson 54:84ef2b29cf7e 49 {
andrewboyson 54:84ef2b29cf7e 50 if (*p == 0) return;
andrewboyson 54:84ef2b29cf7e 51 if (*p == '?')
andrewboyson 54:84ef2b29cf7e 52 {
andrewboyson 54:84ef2b29cf7e 53 *p = 0; //Terminate the path
andrewboyson 54:84ef2b29cf7e 54 *ppQuery = p + 1; //Record the start of the query
andrewboyson 54:84ef2b29cf7e 55 }
andrewboyson 54:84ef2b29cf7e 56 p++;
andrewboyson 54:84ef2b29cf7e 57 }
andrewboyson 54:84ef2b29cf7e 58 *p = 0; //Terminate the path or query
andrewboyson 54:84ef2b29cf7e 59 }
andrewboyson 110:67c96c143c2a 60 static void splitHeader(char* p, char** ppName, char** ppValue)
andrewboyson 54:84ef2b29cf7e 61 {
andrewboyson 54:84ef2b29cf7e 62 *ppName = p; //Record the start of the name
andrewboyson 54:84ef2b29cf7e 63 *ppValue = NULL;
andrewboyson 54:84ef2b29cf7e 64
andrewboyson 54:84ef2b29cf7e 65 while (*p != ':') //Loop to an ':'
andrewboyson 54:84ef2b29cf7e 66 {
andrewboyson 54:84ef2b29cf7e 67 if (!*p) return;
andrewboyson 54:84ef2b29cf7e 68 p++;
andrewboyson 54:84ef2b29cf7e 69 }
andrewboyson 54:84ef2b29cf7e 70 *p = 0; //Terminate the name by replacing the ':' with a NUL char
andrewboyson 54:84ef2b29cf7e 71 p++;
andrewboyson 54:84ef2b29cf7e 72 while (*p == ' ') //Move past any spaces
andrewboyson 54:84ef2b29cf7e 73 {
andrewboyson 54:84ef2b29cf7e 74 if (*p == 0) return;
andrewboyson 54:84ef2b29cf7e 75 p++;
andrewboyson 54:84ef2b29cf7e 76 }
andrewboyson 54:84ef2b29cf7e 77 *ppValue = p; //Record the start of the value
andrewboyson 54:84ef2b29cf7e 78 }
andrewboyson 117:a725e5ad4fad 79 void HttpRequestRead(char *pData, int len, char** ppMethod, char** ppPath, char** ppQuery, char** ppLastModified)
andrewboyson 54:84ef2b29cf7e 80 {
andrewboyson 54:84ef2b29cf7e 81 char* pEnd = pData + len;
andrewboyson 110:67c96c143c2a 82 char* pThis = pData;
andrewboyson 110:67c96c143c2a 83 char* pNext = terminateThisAndGetNextLine(pThis, pEnd);
andrewboyson 110:67c96c143c2a 84 splitRequest(pThis, ppMethod, ppPath, ppQuery);
andrewboyson 54:84ef2b29cf7e 85
andrewboyson 117:a725e5ad4fad 86 *ppLastModified = NULL; //Return NULL if no 'If-Modified-Since' line
andrewboyson 54:84ef2b29cf7e 87 while(pNext)
andrewboyson 54:84ef2b29cf7e 88 {
andrewboyson 54:84ef2b29cf7e 89 pThis = pNext;
andrewboyson 110:67c96c143c2a 90 pNext = terminateThisAndGetNextLine(pThis, pEnd);
andrewboyson 54:84ef2b29cf7e 91 if (*pThis == 0) break; //This line is empty ie no more headers
andrewboyson 54:84ef2b29cf7e 92 char* pName;
andrewboyson 54:84ef2b29cf7e 93 char* pValue;
andrewboyson 110:67c96c143c2a 94 splitHeader(pThis, &pName, &pValue);
andrewboyson 54:84ef2b29cf7e 95 if (strcmp(pName, "If-Modified-Since") == 0) *ppLastModified = pValue;
andrewboyson 54:84ef2b29cf7e 96 }
andrewboyson 54:84ef2b29cf7e 97 }