105 lines
4.2 KiB
C
105 lines
4.2 KiB
C
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/*
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* Copyright (C) 2016 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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#pragma once
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#include "linker.h"
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#include "linker_debug.h"
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#include <algorithm>
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#include "private/CFIShadow.h"
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// This class keeps the contents of CFI shadow up-to-date with the current set of loaded libraries.
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// See the comment in CFIShadow.h for more context.
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// See documentation in http://clang.llvm.org/docs/ControlFlowIntegrityDesign.html#shared-library-support.
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//
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// Shadow is mapped and initialized lazily as soon as the first CFI-enabled DSO is loaded.
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// It is updated after any library is loaded (but before any constructors are ran), and
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// before any library is unloaded.
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class CFIShadowWriter : private CFIShadow {
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// Returns pointer to the shadow element for an address.
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uint16_t* MemToShadow(uintptr_t x) {
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return reinterpret_cast<uint16_t*>(*shadow_start + MemToShadowOffset(x));
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}
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// Update shadow for the address range to the given constant value.
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void AddConstant(uintptr_t begin, uintptr_t end, uint16_t v);
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// Update shadow for the address range to kUncheckedShadow.
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void AddUnchecked(uintptr_t begin, uintptr_t end);
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// Update shadow for the address range to kInvalidShadow.
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void AddInvalid(uintptr_t begin, uintptr_t end);
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// Update shadow for the address range to the given __cfi_check value.
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void Add(uintptr_t begin, uintptr_t end, uintptr_t cfi_check);
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// Add a DSO to CFI shadow.
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bool AddLibrary(soinfo* si);
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// Map CFI shadow.
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uintptr_t MapShadow();
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// Initialize CFI shadow and update its contents for everything in solist if any loaded library is
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// CFI-enabled. If new_si != nullptr, do an incremental check by looking only at new_si; otherwise
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// look at the entire solist.
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bool MaybeInit(soinfo *new_si, soinfo *solist);
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// Set a human readable name for the entire shadow region.
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void FixupVmaName();
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// Pass the pointer to the mapped shadow region to libdl. Must only be called once.
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// Flips shadow_start to a non-nullptr value.
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bool NotifyLibDl(soinfo *solist, uintptr_t p);
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// Pointer to the shadow start address.
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uintptr_t *shadow_start;
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bool initial_link_done;
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public:
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// Update shadow after loading a DSO.
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// This function will initialize the shadow if it sees a CFI-enabled DSO for the first time.
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// In that case it will retroactively update shadow for all previously loaded DSOs. "solist" is a
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// pointer to the global list.
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// This function must be called before any user code has observed the newly loaded DSO.
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bool AfterLoad(soinfo* si, soinfo *solist);
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// Update shadow before unloading a DSO.
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void BeforeUnload(soinfo* si);
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// This is called as soon as the initial set of libraries is linked.
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bool InitialLinkDone(soinfo *solist);
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// Handle failure to locate __cfi_check for a target address.
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static void CfiFail(uint64_t CallSiteTypeId, void* Ptr, void* DiagData, void *caller_pc);
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};
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CFIShadowWriter* get_cfi_shadow();
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