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Next set of additional error checks for invalid Mach-O files for bad load commands

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that use the Mach::linkedit_data_command type for the load commands that are
currently used in the MachOObjectFile constructor.

This contains the missing checks for LC_DATA_IN_CODE and
LC_LINKER_OPTIMIZATION_HINT load commands and the fields for the
Mach::linkedit_data_command type.  Checking for other load commands that
use this type will be added later.

Also fixed a couple of places that was using sizeof(MachOObjectFile::LoadCommandInfo)
that should have been using sizeof(MachO::load_command).

llvm-svn: 280267
This commit is contained in:
Kevin Enderby
2016-08-31 17:57:46 +00:00
parent 2700bd831a
commit 9d0c945ad6
7 changed files with 52 additions and 12 deletions
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48
llvm/lib/Object/MachOObjectFile.cpp
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@@ -184,7 +184,7 @@ static Expected<MachOObjectFile::LoadCommandInfo>
getFirstLoadCommandInfo(const MachOObjectFile *Obj) {
unsigned HeaderSize = Obj->is64Bit() ? sizeof(MachO::mach_header_64)
: sizeof(MachO::mach_header);
if (sizeof(MachOObjectFile::LoadCommandInfo) > Obj->getHeader().sizeofcmds)
if (sizeof(MachO::load_command) > Obj->getHeader().sizeofcmds)
return malformedError("load command 0 extends past the end all load "
"commands in the file");
return getLoadCommandInfo(Obj, getPtr(Obj, HeaderSize), 0);
@@ -195,7 +195,7 @@ getNextLoadCommandInfo(const MachOObjectFile *Obj, uint32_t LoadCommandIndex,
const MachOObjectFile::LoadCommandInfo &L) {
unsigned HeaderSize = Obj->is64Bit() ? sizeof(MachO::mach_header_64)
: sizeof(MachO::mach_header);
if (L.Ptr + L.C.cmdsize + sizeof(MachOObjectFile::LoadCommandInfo) >
if (L.Ptr + L.C.cmdsize + sizeof(MachO::load_command) >
Obj->getData().data() + HeaderSize + Obj->getHeader().sizeofcmds)
return malformedError("load command " + Twine(LoadCommandIndex + 1) +
" extends past the end all load commands in the file");
@@ -474,6 +474,36 @@ static Error checkDysymtabCommand(const MachOObjectFile *Obj,
return Error::success();
}
static Error checkLinkeditDataCommand(const MachOObjectFile *Obj,
const MachOObjectFile::LoadCommandInfo &Load,
uint32_t LoadCommandIndex,
const char **LoadCmd, const char *CmdName) {
if (Load.C.cmdsize < sizeof(MachO::linkedit_data_command))
return malformedError("load command " + Twine(LoadCommandIndex) + " " +
CmdName + " cmdsize too small");
if (*LoadCmd != nullptr)
return malformedError("more than one " + Twine(CmdName) + " command");
MachO::linkedit_data_command LinkData =
getStruct<MachO::linkedit_data_command>(Obj, Load.Ptr);
if (LinkData.cmdsize != sizeof(MachO::linkedit_data_command))
return malformedError(Twine(CmdName) + " command " +
Twine(LoadCommandIndex) + " has incorrect cmdsize");
uint64_t FileSize = Obj->getData().size();
if (LinkData.dataoff > FileSize)
return malformedError("dataoff field of " + Twine(CmdName) + " command " +
Twine(LoadCommandIndex) + " extends past the end of "
"the file");
uint64_t BigSize = LinkData.dataoff;
BigSize += LinkData.datasize;
if (BigSize > FileSize)
return malformedError("dataoff field plus datasize field of " +
Twine(CmdName) + " command " +
Twine(LoadCommandIndex) + " extends past the end of "
"the file");
*LoadCmd = Load.Ptr;
return Error::success();
}
Expected<std::unique_ptr<MachOObjectFile>>
MachOObjectFile::create(MemoryBufferRef Object, bool IsLittleEndian,
bool Is64Bits) {
@@ -550,19 +580,13 @@ MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
if ((Err = checkDysymtabCommand(this, Load, I, &DysymtabLoadCmd)))
return;
} else if (Load.C.cmd == MachO::LC_DATA_IN_CODE) {
// Multiple data in code tables
if (DataInCodeLoadCmd) {
Err = malformedError("Multiple data-in-code tables");
if ((Err = checkLinkeditDataCommand(this, Load, I, &DataInCodeLoadCmd,
"LC_DATA_IN_CODE")))
return;
}
DataInCodeLoadCmd = Load.Ptr;
} else if (Load.C.cmd == MachO::LC_LINKER_OPTIMIZATION_HINT) {
// Multiple linker optimization hint tables
if (LinkOptHintsLoadCmd) {
Err = malformedError("Multiple linker optimization hint tables");
if ((Err = checkLinkeditDataCommand(this, Load, I, &LinkOptHintsLoadCmd,
"LC_LINKER_OPTIMIZATION_HINT")))
return;
}
LinkOptHintsLoadCmd = Load.Ptr;
} else if (Load.C.cmd == MachO::LC_DYLD_INFO ||
Load.C.cmd == MachO::LC_DYLD_INFO_ONLY) {
// Multiple dyldinfo load commands