buffer​ overflow

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buffer overflow

*** stack smashing detected ***
A buffer​ overflow occurs when the user input exceeds the buffer capacity. 
https://www.educative.io/edpresso/what-is-the-stack-smashing-detected-error

Find the potential exception
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void* memcpy(void* pvTo, void* pvFrom, size_t size){
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​
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    byte* pbTo = (byte*)pvTo;
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    byte* pbFrom = (byte*)pvFrom;
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​
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​
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    while(size-- > 0)
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        *pbTo++ = *pbFrom++;
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​
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​
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    return pvTo;
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}
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Code:
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#include <stdio.h>
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typedef unsigned char byte;
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​
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void* z_memcpy(void* restrict pvTo, void* pvFrom, size_t size){
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    byte* pbTo = (byte*)pvTo;
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    byte* pbFrom = (byte*)pvFrom;
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​
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​
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    while(size-- > 0){
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        printf("TO: %c, From: %c \n", *pbTo, *pbFrom);
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        *pbTo++ = *pbFrom++;
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    }
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    return pvTo;
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}
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Test code
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int main() {
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    char to[4] = "";
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    char from[] = "abcdefg";
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​
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    z_memcpy(to, from, 14);
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​
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    return 0;
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}
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*** stack smashing detected ***

Find the potential exception

Code: