[PATCH] elf: do not run FINI functions if object has not been initialized

[Waldemar Kozaczuk]

If dynamic linker fails to load a library object because
for example it is not a valid ELF, it would try to run FINI
functions as it unloads it and crash with a page fault.

This patch tweaks dynamic linker logic to skip running
FINI functions if object has not been fully initialized.

Signed-off-by: Waldemar Kozaczuk <jwkoz...@gmail.com>
---
core/elf.cc | 4 ++++
include/osv/elf.hh | 1 +
2 files changed, 5 insertions(+)

diff --git a/core/elf.cc b/core/elf.cc
index 349e3515..a61bb035 100644
--- a/core/elf.cc
+++ b/core/elf.cc
@@ -1057,11 +1057,15 @@ void object::run_init_funcs(int argc, char** argv)
funcs[i](argc, argv);
}
}
+ _initialized = true;
}

// Run the object's static destructors or similar finalization
void object::run_fini_funcs()
{
+ if (!_initialized) {
+ return;
+ }
if (dynamic_exists(DT_FINI_ARRAY)) {
auto funcs = dynamic_ptr<void (*)()>(DT_FINI_ARRAY);
auto nr = dynamic_val(DT_FINI_ARRAYSZ) / sizeof(*funcs);
diff --git a/include/osv/elf.hh b/include/osv/elf.hh
index 4466b2ab..7043ec74 100644
--- a/include/osv/elf.hh
+++ b/include/osv/elf.hh
@@ -423,6 +423,7 @@ protected:
ulong _module_index;
std::unique_ptr<char[]> _section_names_cache;
bool _is_executable;
+ bool _initialized = false;
bool is_core();

std::unordered_map<std::string,void*> _cached_symbols;
--
2.20.1