183ad9df53
Add flags and a file descriptor to android_dlopen_ext() to allow writing the RELRO section of the loaded library to a file after relocation processing, and to allow mapping identical pages from the file over the top of relocated memory in another process. Explicitly comparing the pages is required in case a page contains a reference to a symbol defined in another library loaded at a random base address. Bug: 13005501 Change-Id: Ibb5b2d384edfaa5acf3e97a5f8b6115c10497a1e
108 lines
3.9 KiB
C++
108 lines
3.9 KiB
C++
/*
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* Copyright (C) 2012 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef LINKER_PHDR_H
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#define LINKER_PHDR_H
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/* Declarations related to the ELF program header table and segments.
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*
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* The design goal is to provide an API that is as close as possible
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* to the ELF spec, and does not depend on linker-specific data
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* structures (e.g. the exact layout of struct soinfo).
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*/
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#include "linker.h"
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class ElfReader {
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public:
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ElfReader(const char* name, int fd);
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~ElfReader();
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bool Load(const android_dlextinfo* extinfo);
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size_t phdr_count() { return phdr_num_; }
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ElfW(Addr) load_start() { return reinterpret_cast<ElfW(Addr)>(load_start_); }
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size_t load_size() { return load_size_; }
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ElfW(Addr) load_bias() { return load_bias_; }
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const ElfW(Phdr)* loaded_phdr() { return loaded_phdr_; }
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private:
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bool ReadElfHeader();
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bool VerifyElfHeader();
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bool ReadProgramHeader();
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bool ReserveAddressSpace(const android_dlextinfo* extinfo);
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bool LoadSegments();
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bool FindPhdr();
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bool CheckPhdr(ElfW(Addr));
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const char* name_;
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int fd_;
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ElfW(Ehdr) header_;
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size_t phdr_num_;
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void* phdr_mmap_;
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ElfW(Phdr)* phdr_table_;
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ElfW(Addr) phdr_size_;
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// First page of reserved address space.
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void* load_start_;
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// Size in bytes of reserved address space.
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size_t load_size_;
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// Load bias.
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ElfW(Addr) load_bias_;
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// Loaded phdr.
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const ElfW(Phdr)* loaded_phdr_;
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};
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size_t phdr_table_get_load_size(const ElfW(Phdr)* phdr_table, size_t phdr_count,
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ElfW(Addr)* min_vaddr = NULL, ElfW(Addr)* max_vaddr = NULL);
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int phdr_table_protect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias);
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int phdr_table_unprotect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias);
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int phdr_table_protect_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias);
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int phdr_table_serialize_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias,
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int fd);
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int phdr_table_map_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias,
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int fd);
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#if defined(__arm__)
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int phdr_table_get_arm_exidx(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias,
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ElfW(Addr)** arm_exidx, unsigned* arm_exidix_count);
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#endif
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void phdr_table_get_dynamic_section(const ElfW(Phdr)* phdr_table, size_t phdr_count,
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ElfW(Addr) load_bias,
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ElfW(Dyn)** dynamic, size_t* dynamic_count, ElfW(Word)* dynamic_flags);
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#endif /* LINKER_PHDR_H */
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