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LibELF: Correctly determine symbol amount for DT_GNU_HASH table

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Ollrogge 2024-01-07 20:10:39 +01:00 • committed by Andrew Kaster
parent eada4f2ee8
commit 90ff6cca8a
2 changed files with 33 additions and 5 deletions
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37
Userland/Libraries/LibELF/DynamicObject.cpp
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@ -216,10 +216,39 @@ void DynamicObject::parse()
m_size_of_relocation_table -= m_size_of_plt_relocation_entry_list;
}
auto hash_section_address = hash_section().address().as_ptr();
// TODO: consider base address - it might not be zero
auto num_hash_chains = ((u32*)hash_section_address)[1];
m_symbol_count = num_hash_chains;
u32 const* hash_table_begin = reinterpret_cast<u32 const*>(hash_section().address().as_ptr());
if (m_hash_type == HashType::SYSV) {
u32 n_chain = hash_table_begin[1];
m_symbol_count = n_chain;
return;
}
// Determine amount of symbols by finding the chain with the highest
// starting index and walking this chain until the end to find the
// maximum index = amount of symbols.
using BloomWord = FlatPtr;
size_t const num_buckets = hash_table_begin[0];
size_t const num_omitted_symbols = hash_table_begin[1];
u32 const num_maskwords = hash_table_begin[2];
BloomWord const* bloom_words = reinterpret_cast<BloomWord const*>(&hash_table_begin[4]);
u32 const* const buckets = reinterpret_cast<u32 const*>(&bloom_words[num_maskwords]);
u32 const* const chains = &buckets[num_buckets];
size_t highest_chain_idx = 0;
for (size_t i = 0; i < num_buckets; i++) {
if (buckets[i] > highest_chain_idx) {
highest_chain_idx = buckets[i];
}
}
size_t amount_symbols = highest_chain_idx;
u32 const* last_chain = &chains[highest_chain_idx - num_omitted_symbols];
while ((*(last_chain++) & 1) == 0) {
amount_symbols++;
}
m_symbol_count = amount_symbols + 1;
}
DynamicObject::Relocation DynamicObject::RelocationSection::relocation(unsigned index) const