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I am trying to use LD_PRELOAD to preload a library with an application that has setuid permissions. Tried LD_PRELOAD at first, and it seemed like it was being ignored with the setuid binary, though it was working when I tried it with others like ls , dir etc. From the documentation of LD_PRELOAD: LD_PRELOAD A whitespace-separated list of additional, user-specified, ELF shared libraries to be loaded before all others. This can be used to selectively override functions in other shared libraries. For set- user-ID/set-group-ID ELF binaries, only libraries in the standard search directories that are also set-user-ID will be loaded. I tried to put the library in /usr/lib , /usr/local/lib , and /usr/lib64 with setuid permissions as per this documentation above, but it still doesnt seem to work. If I dont give LD_PRELOAD a path in the case where I have the library in the standard dirs with setuid, it cannot seem to find the library. If I give it the path, it does not do anything. The setuid binary is a root permissions binary that runs in a non root user shell. Any thoughts? Not sure if I am missing a path, an environment variable, or I am misunderstanding the documentation above. Permissions are as follows: Library: -rwsr-sr-x 1 root root 72580 2012-02-10 07:51 App: -rwsr-xr-x 1 root root 137517601 2012-02-10 env | grep LD LD_LIBRARY_PATH=/usr/lib (I added this manually myself, usually LD_LIBRARY_PATH is empty)

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