Before revision: To fix this unsafe program, use strncpy to prevent a possible buffer overflow.int secure_function(char * user_input) { char dst[BUF_SIZE]; // copy a maximum of BUF_SIZE bytes strncpy(dst, user_input, BUF_SIZE); ] \0 }Another secure alternative is to dynamically allocate memory on the heap using malloc.char * secure_copy(char * src) { size_t len = strlen(src); char * dst = (char *) malloc(len + 1); if (dst != NULL) { strncpy(dst, src, len); // append null terminator dst[len] = '\0'; } return dst; }In the above code snippet, the program attempts to copy the contents of src into dst, while also checking the return value of malloc to ensure that enough memory was able to be allocated for the destination buffer.
After revision: // set the last character in the buffer to NUL, dstBUF_SIZE -1= '';To fix this unsafe program, use strncpy to prevent a possible buffer overflow.int secure_function(char * user_input) { char dst[BUF_SIZE]; // copy a maximum of BUF_SIZE bytes strncpy(dst, user_input, BUF_SIZE); ] \0 }Another secure alternative is to dynamically allocate memory on the heap using malloc.char * secure_copy(char * src) { size_t len = strlen(src); char * dst = (char *) malloc(len + 1); if (dst != NULL) { strncpy(dst, src, len); // append null terminator dst[len] = '\0'; } return dst; }In the above code snippet, the program attempts to copy the contents of src into dst, while also checking the return value of malloc to ensure that enough memory was able to be allocated for the destination buffer.