tree 0df7b4b15d33b6fbce1045666148b270f1e08391
parent 3e4774ebc0b6cacab0b537de32453c8436a97bd1
author Michael Trent <mtrent@apple.com> 1550902796 +0000
committer Michael Trent <mtrent@apple.com> 1550902796 +0000

objdump fails to parse Mach-O binaries with n_desc bearing stabs

Summary:
The objdump Mach-O parser uses MachOObjectFile::checkSymbolTable() to
verify the symbol table is in a legal state before dereferencing the
offsets in the table. This routine missed a test for N_STAB symbols
when validating the two-level name space library ordinal for undefined
symbols. If the binary in question contained a value in the n_desc high
byte that is larger than the list of loaded dylibs, checkSymbolTable()
will flag the library ordinal as being out of range. Most of the time
the n_desc field is set to 0 or to small values, but old final linked
binaries exist with N_STAB symbols bearing non-trivial n_desc fields. 

The change here is simply to verify a symbol is not an N_STAB symbol
before consulting the values of n_other or n_desc.

rdar://44977336

Reviewers: lhames, pete, ab

Reviewed By: pete

Subscribers: llvm-commits, rupprecht

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58568

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354722 91177308-0d34-0410-b5e6-96231b3b80d8