Disadvantages of scanf

Question

I want to know the disadvantages of scanf().

In many sites, I have read that using scanf might cause buffer overflows. What is the reason f

Answer 1

Yes, you are right. There is a major security flaw in scanf family(scanf,sscanf, fscanf..etc) esp when reading a string, because they don't take the length of the buffer (into which they are reading) into account.

Example:

char buf[3];
sscanf("abcdef","%s",buf);

clearly the the buffer buf can hold MAX 3 char. But the sscanf will try to put "abcdef" into it causing buffer overflow.