Open shared object with native client

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David Rönn Jansson

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Oct 27, 2016, 4:30:20 AM10/27/16

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In my nexe, that I've created with the Native Client SDK, I'm trying to load a shared object using dlopen(). When I try that I receive the error: libxxxx.so.1.6: failed to load code from shared object: Invalid argument

When I search for information about the error I don't find much, but some answers indicate that it's not loaded because it doesn't validate in Native clients check. (see further down about validation) Also, I thought I just should mention: I can see in the access log of the webserver that it's fetching the file, "GET /glibc/Release/lib64/libxxxx.so.1.6 HTTP/1.1" 200

If I try to validate libtts_engine.so I receive the following output: $ nacl_sdk/pepper_49/tools/ncval libxxxx.so.1.6

1b4844: Text segment size (0x1b4844) is not multiple of bundle size. Invalid.

I believe this is a bad sign. Have I misunderstood something if I say that this means that the libxxxx.so.1.6 file doesn't pass the validation of native client?

If I run the same code, except that I'm trying to load the file "libeightball_x86_64.so" that is compiled from /nacl_sdk/example/tutorial/dlopen it loads and runs without problem.

When I did the test above, I have added libxxxx.so.1.6 and all of the libraries used by libxxxx.so.1.6 in the manifest file (.nmf) of the project.

Have any of you had problems linking precompiled, third-party libraries together with your Native client applications?

Bennet Yee (余仕斌)

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Oct 27, 2016, 1:33:46 PM10/27/16

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if the precompiled, third-party libraries were not compiled with the native client compilers or some other modified compilers to ensure that the generated code will satisfy the native client validation rules, then the dlopen will fail. everybody should have problems with such libraries. the reason is simple: if dlopen allows injecting code that do not follow the native client rules, then this would be a trivial sandbox bypass.

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