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Date: Wed, 6 Feb 2019 21:25:18 +0100
From: Markus Wichmann <nullplan@....net>
To: musl@...ts.openwall.com
Cc: Alexey Izbyshev <izbyshev@...ras.ru>
Subject: Re: dlsym(handle) may search in unrelated libraries

On Wed, Feb 06, 2019 at 08:02:28PM +0300, Alexey Izbyshev wrote:
> Unfortunately, my test case was a simplified example of a general problem:
> dso->deps is assigned only for the main app and for libraries opened with
> dlopen(), but not for their dependencies. Consider the following:

Right you are. It took me a while to understand what the deps array was
even for (since musl's dlclose() doesn't do anything, tracking
dependencies is mostly pointless), but I found it is needed for lazy
relocation processing. So it is necessary for all libs opened by
dlopen() directly to contain a list of all their dependencies. All the
other libs can have an empty list.

So I propose the attached patch in addition to the previous one. This
will set dso->deps to the empty list in all libs not directly loaded
from dlopen(). The previous patch is still necessary, as nothing ever
calls load_deps() on the libc or the vdso, but all other modules get a
load_deps() treatment.

> 
> Alexey
> 
> 

Ciao,
Markus

View attachment "0007-Initialize-deps-on-non-directly-loaded-libs.patch" of type "text/x-diff" (966 bytes)

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