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[Object, MachO] Don't crash on invalid MachO load commands.

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Summary:
Currently all load commands are parsed in MachOObjectFile constructor.
If the next load command cannot be parsed, or if command size is too
small, properly report it through the error code and fail to construct
the object, instead of crashing the program.

Test Plan: regression test suite

Reviewers: rafael, filcab

Subscribers: llvm-commits

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239080 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Alexey Samsonov
2015-06-04 19:57:46 +00:00
parent 08a382531c
commit 7e699dce03
4 changed files with 28 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
lib/Object/MachOObjectFile.cpp
View File

@ -194,24 +194,27 @@ static uint32_t getSectionFlags(const MachOObjectFile *O,
return Sect.flags;
}
static MachOObjectFile::LoadCommandInfo
static ErrorOr<MachOObjectFile::LoadCommandInfo>
getLoadCommandInfo(const MachOObjectFile *Obj, const char *Ptr) {
auto CmdOrErr = getStructOrErr<MachO::load_command>(Obj, Ptr);
if (!CmdOrErr)
return CmdOrErr.getError();
if (CmdOrErr->cmdsize < 8)
return object_error::macho_small_load_command;
MachOObjectFile::LoadCommandInfo Load;
Load.Ptr = Ptr;
Load.C = getStruct<MachO::load_command>(Obj, Load.Ptr);
if (Load.C.cmdsize < 8)
report_fatal_error("Load command with size < 8 bytes.");
Load.C = CmdOrErr.get();
return Load;
}
static MachOObjectFile::LoadCommandInfo
static ErrorOr<MachOObjectFile::LoadCommandInfo>
getFirstLoadCommandInfo(const MachOObjectFile *Obj) {
unsigned HeaderSize = Obj->is64Bit() ? sizeof(MachO::mach_header_64)
: sizeof(MachO::mach_header);
return getLoadCommandInfo(Obj, getPtr(Obj, HeaderSize));
}
static MachOObjectFile::LoadCommandInfo
static ErrorOr<MachOObjectFile::LoadCommandInfo>
getNextLoadCommandInfo(const MachOObjectFile *Obj,
const MachOObjectFile::LoadCommandInfo &L) {
return getLoadCommandInfo(Obj, L.Ptr + L.C.cmdsize);
@ -251,7 +254,12 @@ MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
MachO::LoadCommandType SegmentLoadType = is64Bit() ?
MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT;
LoadCommandInfo Load = getFirstLoadCommandInfo(this);
auto LoadOrErr = getFirstLoadCommandInfo(this);
if (!LoadOrErr) {
EC = LoadOrErr.getError();
return;
}
LoadCommandInfo Load = LoadOrErr.get();
for (unsigned I = 0; I < LoadCommandCount; ++I) {
LoadCommands.push_back(Load);
if (Load.C.cmd == MachO::LC_SYMTAB) {
@ -318,8 +326,14 @@ MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
Load.C.cmd == MachO::LC_LOAD_UPWARD_DYLIB) {
Libraries.push_back(Load.Ptr);
}
if (I < LoadCommandCount - 1)
Load = getNextLoadCommandInfo(this, Load);
if (I < LoadCommandCount - 1) {
auto LoadOrErr = getNextLoadCommandInfo(this, Load);
if (!LoadOrErr) {
EC = LoadOrErr.getError();
return;
}
Load = LoadOrErr.get();
}
}
assert(LoadCommands.size() == LoadCommandCount);
}