From bcba39ab9c8c4d2faeff70774fca91b1efec79e3 Mon Sep 17 00:00:00 2001
From: George Rimar <grimar@accesssoftek.com>
Date: Wed, 2 Nov 2016 10:16:25 +0000
Subject: [PATCH] [ELF] - Check that .dynsym is present in DSO if
 SHT_GNU_versym section is.

When we have SHT_GNU_versym section, it is should be associated with symbol table
section. Usually (and in out implementation) it is .dynsym.
In case when .dynsym is absent (due to broken object for example),
lld crashes in parseVerdefs() when accesses null pointer:

Versym = reinterpret_cast<const Elf_Versym *>(this->ELFObj.base() +
                                              VersymSec->sh_offset) +
         this->Symtab->sh_info;

DIfferential revision: https://reviews.llvm.org/D25553

llvm-svn: 285796
---
 lld/ELF/InputFiles.cpp                     |  3 +++
 lld/ELF/SymbolTable.cpp                    |  2 +-
 lld/test/ELF/invalid/verdef-no-symtab.test | 26 ++++++++++++++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 lld/test/ELF/invalid/verdef-no-symtab.test

diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index 6900f8f325d8..25fff944c2e4 100644
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -610,6 +610,9 @@ template <class ELFT> void SharedFile<ELFT>::parseSoName() {
     }
   }
 
+  if (this->VersymSec && !this->Symtab)
+    error("SHT_GNU_versym should be associated with symbol table");
+
   this->initStringTable();
 
   // DSOs are identified by soname, and they usually contain
diff --git a/lld/ELF/SymbolTable.cpp b/lld/ELF/SymbolTable.cpp
index c45ab94d0b57..0d8c62dd4751 100644
--- a/lld/ELF/SymbolTable.cpp
+++ b/lld/ELF/SymbolTable.cpp
@@ -77,7 +77,7 @@ template <class ELFT> void SymbolTable<ELFT>::addFile(InputFile *File) {
   if (auto *F = dyn_cast<SharedFile<ELFT>>(File)) {
     // DSOs are uniquified not by filename but by soname.
     F->parseSoName();
-    if (!SoNames.insert(F->getSoName()).second)
+    if (HasError || !SoNames.insert(F->getSoName()).second)
       return;
     SharedFiles.push_back(F);
     F->parseRest();
diff --git a/lld/test/ELF/invalid/verdef-no-symtab.test b/lld/test/ELF/invalid/verdef-no-symtab.test
new file mode 100644
index 000000000000..5b5c32e4ff5c
--- /dev/null
+++ b/lld/test/ELF/invalid/verdef-no-symtab.test
@@ -0,0 +1,26 @@
+# RUN: yaml2obj %s -o %t
+# RUN: not ld.lld %t -o %tout 2>&1 | FileCheck %s
+
+## When we have SHT_GNU_versym section, it is should be associated
+## with symbol table section.
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .versym
+    Type:            SHT_GNU_versym
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x1
+    Content:         "00000000"
+
+  - Name:            .verdef
+    Type:            SHT_GNU_verdef
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x1
+    Content:         "00000000"
+
+
+# CHECK: SHT_GNU_versym should be associated with symbol table