Re: LD_PRELOAD problem

  • From: "LS Cheng" <exriscer@xxxxxxxxx>
  • To: "Tanel Poder" <tanel.poder.003@xxxxxxx>
  • Date: Fri, 1 Sep 2006 14:16:32 +0200

I make a pardon the binary which I chatr'ed was sqlplus


On 9/1/06, LS Cheng <exriscer@xxxxxxxxx> wrote:

Hi all

I have more information, I did a chatr to check differences between
working server oracle binary and the non working.

I see two differences, in the server which LD_PRELOAD doesnt cause problem
oracle binary has these two attributes:

explicit unloading disabled
linkage table protection disabled

Does anyone know how can I change these attributes with chatr?


On 8/31/06, Tanel Poder <tanel.poder.003@xxxxxxx> wrote:

>  LD_PRELOAD allows you to hijack dynamicly loaded library functions. If
> sqlplus calls function X, then if this function X is exported from your
> /sbl/ then this function X is called from /sbl/ even if it
> exists in some other dll against which the executable is linked (like
> libclntsh* libraries).
> Run: nm /sbl/ to see which functions may be hijacked there, this
> could give some more indication what's going on.
> And of course, the library's word-size has to match word-size of the
> executable. If the word sizes are different, you have to recompile the
> library.
> Tanel.
>  ------------------------------
> *From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:
> oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *LS Cheng
> *Sent:* Thursday, August 31, 2006 04:45
> *To:* Jesse, Rich
> *Cc:* oracle-l
> *Subject:* Re: LD_PRELOAD problem
> However when I unset LD_PRELOAD sqlplus works but of course the
> application specific program fails.

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