From 9a1030a4d6febc9133de25dce7cda1bae513e8cf Mon Sep 17 00:00:00 2001
From: Filipe Cabecinhas <me@filcab.net>
Date: Tue, 14 Apr 2015 14:07:15 +0000
Subject: [PATCH] Error out of ParseBitcodeInto(Module*) if we haven't read a
 Module

Summary:
Without this check the following case failed:

Skip a SubBlock which is not a MODULE_BLOCK_ID nor a BLOCKINFO_BLOCK_ID
Got to end of file

TheModule would still be == nullptr, and we would subsequentially fail
when materializing the Module (assert at the start of
BitcodeReader::MaterializeModule).

Bug found with AFL.

Reviewers: dexonsmith, rafael

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9014

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234887 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Bitcode/Reader/BitcodeReader.cpp            |   8 ++++++--
 test/Bitcode/Inputs/invalid-no-proper-module.bc | Bin 0 -> 612 bytes
 test/Bitcode/invalid.test                       |   5 +++++
 3 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 test/Bitcode/Inputs/invalid-no-proper-module.bc

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 149642b1b3e..bd4d70b25aa 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -3063,8 +3063,12 @@ std::error_code BitcodeReader::ParseBitcodeInto(Module *M,
   // We expect a number of well-defined blocks, though we don't necessarily
   // need to understand them all.
   while (1) {
-    if (Stream.AtEndOfStream())
-      return std::error_code();
+    if (Stream.AtEndOfStream()) {
+      if (TheModule)
+        return std::error_code();
+      // We didn't really read a proper Module.
+      return Error("Malformed IR file");
+    }
 
     BitstreamEntry Entry =
       Stream.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
diff --git a/test/Bitcode/Inputs/invalid-no-proper-module.bc b/test/Bitcode/Inputs/invalid-no-proper-module.bc
new file mode 100644
index 0000000000000000000000000000000000000000..6d5a291db6317efd82a5530e9bc8421c4396d8d1
GIT binary patch
literal 612
zcmZ>AK5%a#4+FzA1_lQ1CItp2AT0#M?2XD39Z#@$vI!VjPGW4~QDx<jlw;{mYT$8Y
za+<{Llp<gxV!<Kd$z|lC;=wgRQTa$v1COL)kqY~X69P#q7OZeM_JI*-PNxC`0~e4s
zQaZt*kkZOBS#e1Vka*m(aDs@CPg@UnONx(xfHFfdi-({9&|>E)AYDKpu?XlY5I7)^
z3Sls`X)r@r1}>5iMuXxhsN9o81_nVO+nA$4=Ey^tG!aJI4rhy&!#z$7?3ESl#WM<d
zo-y#h72x~Qz-P?kBzNeb?74+9X$GudWzEuOm~Bru+x9Tq0?jB?U|`??(ryYC6M1<Y
zj3o{z$ab>|beFh<8N~RdFtI4ef~;alRA6A>2hzeUj;se~D#RRUd&uG@V1A$gC=Sxk
z9w2a5Br#1PW~;1#pyJgw2bY$VXeL3yOSxPwE*=&@6%aGHfi%br##ssp42K&T*noU&
udZE4t+Y8g<I7=agSUn&&f$V8avJhawv;!ytaSu%0K_b;LCgU~_WF`PzhJP>s

literal 0
HcmV?d00001

diff --git a/test/Bitcode/invalid.test b/test/Bitcode/invalid.test
index 0eacb9dbbb1..9cab227ab19 100644
--- a/test/Bitcode/invalid.test
+++ b/test/Bitcode/invalid.test
@@ -50,3 +50,8 @@ EXTRACT-IDXS: EXTRACTVAL: Invalid type
 INSERT-ARRAY: INSERTVAL: Invalid array index
 INSERT-STRUCT: INSERTVAL: Invalid struct index
 INSERT-IDXS: INSERTVAL: Invalid type
+
+RUN: not llvm-dis -disable-output %p/Inputs/invalid-no-proper-module.bc 2>&1 | \
+RUN:   FileCheck --check-prefix=NO-MODULE %s
+
+NO-MODULE: Malformed IR file
-- 
2.34.1