[llvm-readelf] - Do not try to read past the end of the file when dumping the the...

We have unobvious issue in the condition that is used to check
that we do not read past the EOF.

The problem is that the result of "GnuHashTable->nbuckets * 4" expression is uint32.
Because of that it was still possible to overflow it and pass the check.

There was no such problem with the "GnuHashTable->maskwords * sizeof(typename ELFT::Off)"
condition, because of `sizeof` on the right (which gives 64-bits value on x64),
but I've added an explicit conversion to 64-bit value for `GnuHashTable->maskwords` too.

Differential revision: https://reviews.llvm.org/D81103

diff --git a/llvm/test/tools/llvm-readobj/ELF/hash-histogram.test b/llvm/test/tools/llvm-readobj/ELF/hash-histogram.test
index 4ec772a..a9d2455 100644 (file)
--- a/llvm/test/tools/llvm-readobj/ELF/hash-histogram.test
+++ b/llvm/test/tools/llvm-readobj/ELF/hash-histogram.test
@@ -271,7 +271,7 @@ ProgramHeaders:
 
 ## Case A: the 'nbuckets' field is set so that the GNU hash table goes past the end of the file.
 ##         The value of 1 for the NBUCKETS is no-op.
-# RUN: yaml2obj --docnum=6 -D MASKWORDS=4294967295 -D NBUCKETS=1 %s -o %t7
+# RUN: yaml2obj --docnum=6 -D MASKWORDS=0x80000000 -D NBUCKETS=1 %s -o %t7
 # RUN: llvm-readelf --elf-hash-histogram %t7 2>&1 | \
 # RUN:   FileCheck %s -DFILE=%t7 --check-prefix=ERR5 --implicit-check-not="Histogram"
 
@@ -279,7 +279,7 @@ ProgramHeaders:
 
 ## Case B: the 'maskwords' field is set so that the GNU hash table goes past the end of the file.
 ##         The value of 1 for the MASKWORDS is no-op.
-# RUN: yaml2obj --docnum=6 -D MASKWORDS=1 -D NBUCKETS=4294967295 %s -o %t8
+# RUN: yaml2obj --docnum=6 -D MASKWORDS=1 -D NBUCKETS=0x80000000 %s -o %t8
 # RUN: llvm-readelf --elf-hash-histogram %t8 2>&1 | \
 # RUN:   FileCheck %s -DFILE=%t8 --check-prefix=ERR5 --implicit-check-not="Histogram"
 

diff --git a/llvm/tools/llvm-readobj/ELFDumper.cpp b/llvm/tools/llvm-readobj/ELFDumper.cpp
index 861149a..6c197cf 100644 (file)
--- a/llvm/tools/llvm-readobj/ELFDumper.cpp
+++ b/llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -2681,8 +2681,8 @@ static Error checkGNUHashTable(const ELFFile<ELFT> *Obj,
   uint64_t TableOffset = TableData - Obj->base();
   if (IsHeaderValid)
     *IsHeaderValid = TableOffset + /*Header size:*/ 16 < Obj->getBufSize();
-  if (TableOffset + 16 + GnuHashTable->nbuckets * 4 +
-          GnuHashTable->maskwords * sizeof(typename ELFT::Off) >=
+  if (TableOffset + 16 + (uint64_t)GnuHashTable->nbuckets * 4 +
+          (uint64_t)GnuHashTable->maskwords * sizeof(typename ELFT::Off) >=
       Obj->getBufSize())
     return createError("unable to dump the SHT_GNU_HASH "
                        "section at 0x" +