Re: Can't undate running process binary in Solaris?

Frank Cusack wrote On 07/05/07 16:41,:
On Thu, 05 Jul 2007 13:34:23 -0700 Frank Cusack <fcusack@xxxxxxxxxxx> wrote:

On Thu, 05 Jul 2007 03:40:12 -0700 Boltar <boltar2003@xxxxxxxxxxx> wrote:

I'm trying to get a running process to update its own binary but for
some reason under Solaris it doesn't work , the binary remains
unchanged even though no errors are returned from any function. Does
anyone know why this might happen? My test code is below:

...

mptr = (char *)mmap(
NULL,fs.st_size,PROT_READ | PROT_WRITE,MAP_PRIVATE,fd,

^^^^^^^^^^^


Actually, even when you fix that i don't think you'll be able to
update in-place. You will probably get ETXTBUSY or whatever the
error is, if not at mmap() time, than maybe you'll get SEGV or
a bus error when you actually write to memory.

If a program's text is busy (I mean, if a program is running),
Solaris will not let you, e.g., do something like "echo > program".

Or do I have it backwards and it's Linux that doesn't allow this?

Solaris allows the update (I tried it).

I'm not sure what Boltar's goal in self-modifying the
executable is, though. He mentioned this thread in another
having to do with license-enforcement schemes, but I don't
see any way to use self-modification for enforcement (it's
too easy to protect the file against being written, or to
restore an unmodified backup copy). Boltar, what are you
trying to accomplish? Maybe there's an easier way ...

--
Eric.Sosman@xxxxxxx
.

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