CODEWITHSUNDEEP
c++cgccmingwsymbols
user2848398
user2848398

Reputation: 41

Strip out symbols from dll

I have built a dll using MinGW gcc on windows. I used .def to specified exported functions and generated .lib import lib. Then I used strip.exe to strip out the symbols table. I tried objdump and it prints out empty symbol table. But when I use strings.exe, it can still print a bunch of function and class names. Is this a problem? Would others be able to query functions according to the names from the dll?

Upvotes: 3

Views: 4070

Answers (2)

Iuri Covalisin
Iuri Covalisin

Reputation: 645

Read about PE, it has address and name tables. If you clean up name table, no process will be able to locate exported function by name, only by address, that's done by linker, but not dynamically: http://msdn.microsoft.com/en-us/magazine/cc301808.aspx

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There are many ways to secure exported functions from dll,but all of them have published exploits. If you really want to secure your function - create custom calling convention or signature verification at all exported functions.

Upvotes: 3

Brandon
Brandon

Reputation: 23498

All that stripping does to the dll is to remove the debugging symbols. It does NOT remove the functions from the dll. In other words, if someone imports your dll or uses it, they can access only whatever you exported. If you do not want them to be able to access it, simply do not export it.

Also, when you do a release build, it should strip it if you have -s option enabled.

Upvotes: 1

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