Philip Hazel <ph10@???> writes:
> The author of the patch uses strncpy(a,b,n) to mean "copy string b
> to buffer a, which is of length n". This is actually not sensible if
> n is a lot larger than the length of string b. The reason it is not
> sensible is that strncpy() insists on padding out the destination
> buffer with binary zeros to the length given. So, if you call
> strncpy(a, "abc", 4096) for example, you waste a lot of resources
> writing 4092 unnecessary zeros, possibly touching memory pages which
> might otherwise have been left alone.
strncpy() has a far more serious problem: It does not write a
terminating zero if the buffer is full. This means that buffer
overflows can occur later in unexpected places.
Using sprintf() comes with a performance impact, too.
--
Florian Weimer Weimer@???
University of Stuttgart http://CERT.Uni-Stuttgart.DE/people/fw/
RUS-CERT +49-711-685-5973/fax +49-711-685-5898
