Re: diff_tree_stdin

Morten Welinder [off-list ref] writes:

It looks like diff_tree_stdin can overrun the this_header buffer.  Since the
line length is already calculated, a check would be cheap.

I presume you are talking about "line", not this_header[], since
you are talking about something whose length is already
calculated.

The output buffer this_header[] only ever gets two 40-byte SHA1
and a handful more, so probably 128 bytes would be big enough --
the current 1000 is overkill.

The input line[] is first NUL terminated before getting scanned,
and scanning with get_sha1_hex() stops immediately when we see
NUL, and premature NUL makes it fail, so the first
get_sha1_hex() would not overrun.  If the first SHA1 is followed
by garbage then the second get_sha1_hex() would not succeed
without overrunning either.  If line[40] is NUL then we do not
even do the second get_sha1_hex() --- in any case I do not see
overrun.

I am getting tired (it _was_ my GIT day, but unfortunately I had
to be worried about another day-job project during the day X-<),
and I might probably be overlooking something fairly obvious to
you.  Care to explain?

I presume you are talking about "line", not this_header[], since
you are talking about something whose length is already
calculated.

I was talking about this_header.  It gets slightly more than the length
of "line" which is whatever came in from stdin, subject to a 1000 char
limit.

Morten