[Icecast] Icecast segmentation faults

[chiapas at aktivix.org]

hi

i had meant to email back the list with an update to my Icecast issue
but emailed Karl directly instead.  for the sake of completeness i
have my email and Karl's latest reply below.

On 12/02/2008, Karl Heyes <karl at xiph.org> wrote:
> chiapas at aktivix.org wrote:
>  > hi
>  >
>  > On 11/02/2008, Karl Heyes <karl at xiph.org> wrote:
>  >> Can you try out the trunk code?, a source tarball is available at
>  >>  http://people.xiph.org/~brendan/snapshots/icecast/   build with make
>  >>  debug and run with catchsegv if it still shows the problem.
>  >
>  > i've got in touch with my 'rogue' user and got them to reinstall
>  > Oddcast and all's fine for now.  however i am still slightly concerned
>  > that my set-up remains vulnerable to this problem - is it a buffer
>  > overflow issue?  i am reluctant to install the trunk code as it will
>  > mean another service outage for my users and the seg faults have given
>  > us quite a few of those recently...
>
>
> It's impossible for me to say, based on the report you gave, what the
>  exact cause is.  There has been at least one buffer length related issue
>  resolved but I've never seen it appear like that, however there has been
>  a number of race case fixes which have unpredictable effects.  For me to
>  try to confirm the cause would mean for you give me the stack trace of a
>  debug build of icecast, which I'm guessing you would to be built and
>  then swapped into place.
>
>  The difference between that and using trunk is not that big as the
>  changes to trunk have been kept small.  I'd get the latest trunk work,
>  do a make debug build then wait for an appropriate time to swap into
>  place (crash, quiet time etc). You could do a parallel run on a
>  different port to make sure the xml is fine before hand (just copy the
>  xml and change port and log dir).
>
>  As I said before, as developers we would need a stack trace which means
>  either getting a core file or using catchsegv to report the stack trace
>  when the crash occurs.
>
>  eg catchsegv /path/to/icecast -c /path/to/icecast.xml  > out.txt
>
>
>  karl.

many thanks for this Karl.

i cannot recreate this error as i contacted the webcaster and, with
their permission, remotely logged onto their machine and fixed their
set-up of Winamp/Oddcast.

i will keep vigilant for the same error and implement the above
suggestions to generate a stack trace in the event of the same problem
occuring.

thanks again for your swift and helpful responses all.

regards

Chip Scooter