TFTP client crash seems to be caused by missing bounds check in makeargv()

[Erik Auerswald]

Hi,

On 03.09.22 19:07, Erik Auerswald wrote:

On Sat, Sep 03, 2022 at 05:39:45PM +0200, Simon Josefsson wrote:

[...]
did you notice some fuzzing report that wasn't fixed?

I think the following reports have not yet been addressed:

I do intend to look into these issues, but I cannot say when...

[...]
* Problems found in tftp (the code did not change since the report):

   * Untrusted Pointer Dereference in getcmd() at inetutils/src/tftp.c:878
     https://lists.gnu.org/archive/html/bug-inetutils/2021-12/msg00018.html

That seems to be a missing bounds check in makeargv(), similar
to the old, now fixed, code in telnet.

I'll look into creating a nice reproducer instead of the one
found by the fuzzer, adding a test case, and fixing the bug.

There might be an opportunity to refactor the code to avoid
having to fix the same problem again and again….

[...]

Thanks,
Erik