mqtt.cpp createFullTopicStr()

[WSchimi]

Hi Pina,

mqtt.cpp line 78: (fullTopicStr + topicLen+1) = 0; // <-- the 0 is OUT OF ALLOCATED MEMORY!
see allocation at line 74: char fullTopicStr = (char*) calloc(topicLen+1, sizeof(char));

proposal for line 78: fullTopicStr[topicLen] = '\0';

Best regards
Walter

[pinae]

I accepted your suggestion. Thank You for the help!

[WSchimi]

Hi Pina,

mqtt.cpp line 78: (fullTopicStr + topicLen+1) = 0; // <-- the 0 is OUT OF ALLOCATED MEMORY! see allocation at line 74: char fullTopicStr = (char*) calloc(topicLen+1, sizeof(char));

proposal for line 78: fullTopicStr[topicLen] = '\0';

Best regards Walter

Hi Pina,
the ERROR IS NOT FIXED!
The code "(fullTopicStr + topicLen+1) = " writes 1 Byte behind the allocated memory!
Allocation code: "char* fullTopicStr = (char*) calloc(topicLen+1, sizeof(char));"
The management data of the pool or other important data may already be stored there.

Example: topicLen = 20:
-> 21 Bytes are allocated (from Byte *(fullTopicStr+0) till *(fullTopicStr+20) or *(fullTopicStr + topicLen))
-> "(fullTopicStr + topicLen+1) = '\0' writes at Byte 21 behind memory at pointer *fullTopicStr
-> my proposal for line 78: fullTopicStr[topicLen] = '\0'; or *(fullTopicStr + topicLen) = '\0';

Best regards Walter