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354f803ed7
We use llvm-symbolizer in some production systems, and we run it
against all possibly related files, including some that are not
ELF. We noticed that for some of those invalid files, llvm-symbolizer
would crash with SEGFAULT. Here is an example of such a file.
It is due to that in computeSymbolSizes, a loop uses condition
for (unsigned I = 0, N = Addresses.size() - 1; I < N; ++I) {
where if Addresses.size() is 0, N would overflow and causing the loop
to access invalid memory.
Instead of patching the loop conditions, the commit makes so that the
function returns early if Addresses is empty.
Validated by checking that llvm-symbolizer no longer crashes.
Patch by Teng Qin!
Differential Revision: https://reviews.llvm.org/D44285
llvm-svn: 330610
99 lines
3.0 KiB
C++
99 lines
3.0 KiB
C++
//===- SymbolSize.cpp -----------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Object/SymbolSize.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Object/COFF.h"
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#include "llvm/Object/ELFObjectFile.h"
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#include "llvm/Object/MachO.h"
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using namespace llvm;
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using namespace object;
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// Orders increasingly by (SectionID, Address).
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int llvm::object::compareAddress(const SymEntry *A, const SymEntry *B) {
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if (A->SectionID != B->SectionID)
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return A->SectionID < B->SectionID ? -1 : 1;
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if (A->Address != B->Address)
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return A->Address < B->Address ? -1 : 1;
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return 0;
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}
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static unsigned getSectionID(const ObjectFile &O, SectionRef Sec) {
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if (auto *M = dyn_cast<MachOObjectFile>(&O))
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return M->getSectionID(Sec);
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return cast<COFFObjectFile>(O).getSectionID(Sec);
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}
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static unsigned getSymbolSectionID(const ObjectFile &O, SymbolRef Sym) {
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if (auto *M = dyn_cast<MachOObjectFile>(&O))
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return M->getSymbolSectionID(Sym);
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return cast<COFFObjectFile>(O).getSymbolSectionID(Sym);
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}
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std::vector<std::pair<SymbolRef, uint64_t>>
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llvm::object::computeSymbolSizes(const ObjectFile &O) {
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std::vector<std::pair<SymbolRef, uint64_t>> Ret;
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if (const auto *E = dyn_cast<ELFObjectFileBase>(&O)) {
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auto Syms = E->symbols();
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if (Syms.begin() == Syms.end())
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Syms = E->getDynamicSymbolIterators();
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for (ELFSymbolRef Sym : Syms)
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Ret.push_back({Sym, Sym.getSize()});
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return Ret;
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}
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// Collect sorted symbol addresses. Include dummy addresses for the end
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// of each section.
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std::vector<SymEntry> Addresses;
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unsigned SymNum = 0;
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for (symbol_iterator I = O.symbol_begin(), E = O.symbol_end(); I != E; ++I) {
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SymbolRef Sym = *I;
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uint64_t Value = Sym.getValue();
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Addresses.push_back({I, Value, SymNum, getSymbolSectionID(O, Sym)});
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++SymNum;
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}
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for (SectionRef Sec : O.sections()) {
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uint64_t Address = Sec.getAddress();
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uint64_t Size = Sec.getSize();
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Addresses.push_back(
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{O.symbol_end(), Address + Size, 0, getSectionID(O, Sec)});
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}
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if (Addresses.empty())
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return Ret;
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array_pod_sort(Addresses.begin(), Addresses.end(), compareAddress);
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// Compute the size as the gap to the next symbol
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for (unsigned I = 0, N = Addresses.size() - 1; I < N; ++I) {
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auto &P = Addresses[I];
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if (P.I == O.symbol_end())
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continue;
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// If multiple symbol have the same address, give both the same size.
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unsigned NextI = I + 1;
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while (NextI < N && Addresses[NextI].Address == P.Address)
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++NextI;
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uint64_t Size = Addresses[NextI].Address - P.Address;
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P.Address = Size;
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}
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// Assign the sorted symbols in the original order.
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Ret.resize(SymNum);
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for (SymEntry &P : Addresses) {
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if (P.I == O.symbol_end())
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continue;
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Ret[P.Number] = {*P.I, P.Address};
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}
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return Ret;
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}
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