Okay, but I'd really like to have a better understanding...is there somewhere I can go to get a good explanation of library format? I looked for some docs on ELF, but I couldn't find anything technical. Can you tell me *why* I can't get to a function that is listed as being global, just because the header file it is listed in is not given to the client? Thanks, David > On Sat, Jul 28, 2001 at 04:56:39PM -0500, David Christian wrote: > > What I was interested in was whether or not it's possible to call > > unadvertised library functions. Libraries are sort of just archived object > > files, right? If I had an internal function called "int foo()" in the > > library, and someone created a fake header with an "extern int foo();", > > would they be able to access this function? So far, I haven't been able to > > get that to work, but I'm not sure if it's because I'm doing something wrong > > or because there's some reason why it doesn't work. > > Like you said about the license manager, a sufficiently determined > person could get access to the function. It would require some heavy > black magic, though, because the library doesn't advertise that foo > exists and if you ask it where to find the function, it won't be able > (or willing) to tell you. > > In theory, at least, you could set up some code to inspect the library's > binary for foo's entry point and then jumping directly to that address > after setting up the stack appropriately. (OK, it's not quite that > hard to call the function once you've found it, since you could use > a function pointer to get the compiler to handle the stack for you. > But finding it is the hard part anyhow.) > > This would also be version specific. Since you're not using normal > channels to get the function's address, you'll have to find it again > every time the source code or compiler settings are changed. > > -- > With the arrest of Dimitry Sklyarov it has become apparent that it is not > safe for non US software engineers to visit the United States. - Alan Cox > "To prevent unauthorized reading..." - Adobe eBook reader license > _______________________________________________ > tclug-list mailing list > tclug-list at mn-linux.org > https://mailman.mn-linux.org/mailman/listinfo/tclug-list >