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[DebugInfo] Avoid crashing when parsing an invalid unit header in DWP. 

The integrity checks for index entries in DWARFUnitHeader::extract()
might cause the function to return before checking the state of an
Error object, which leads to a crash in runtime. The patch fixes the
issue by moving the checks in a safe place.

Differential Revision: https://reviews.llvm.org/D75177
This commit is contained in:
Igor Kudrin 2020-02-26 21:23:43 +07:00
parent 5754a61e57
commit 044308e9ed
2 changed files with 69 additions and 9 deletions
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19
llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
View File

@ -285,6 +285,16 @@ bool DWARFUnitHeader::extract(DWARFContext &Context,
else
UnitType = DW_UT_compile;
}
if (isTypeUnit()) {
TypeHash = debug_info.getU64(offset_ptr, &Err);
TypeOffset = debug_info.getUnsigned(
offset_ptr, FormParams.getDwarfOffsetByteSize(), &Err);
} else if (UnitType == DW_UT_split_compile || UnitType == DW_UT_skeleton)
DWOId = debug_info.getU64(offset_ptr, &Err);
if (errorToBool(std::move(Err)))
return false;
if (IndexEntry) {
if (AbbrOffset)
return false;
@ -296,15 +306,6 @@ bool DWARFUnitHeader::extract(DWARFContext &Context,
return false;
AbbrOffset = AbbrEntry->Offset;
}
if (isTypeUnit()) {
TypeHash = debug_info.getU64(offset_ptr, &Err);
TypeOffset = debug_info.getUnsigned(
offset_ptr, FormParams.getDwarfOffsetByteSize(), &Err);
} else if (UnitType == DW_UT_split_compile || UnitType == DW_UT_skeleton)
DWOId = debug_info.getU64(offset_ptr, &Err);
if (errorToBool(std::move(Err)))
return false;
// Header fields all parsed, capture the size of this unit header.
assert(*offset_ptr - Offset <= 255 && "unexpected header size");

59
llvm/test/DebugInfo/X86/invalid-cu-length-dwp.s Normal file
View File

@ -0,0 +1,59 @@
# RUN: llvm-mc -triple x86_64-unknown-linux %s -filetype=obj -o - | \
# RUN: llvm-dwarfdump -debug-info -
## llvm-dwarfdump used to crash with this input because of an invalid size
## of the compilation unit contribution in the .debug_cu_index section.
.section .debug_abbrev.dwo, "e", @progbits
.LAbbrBegin:
.uleb128 1 # Abbreviation Code
.uleb128 17 # DW_TAG_compile_unit
.byte 0 # DW_CHILDREN_no
.uleb128 3 # DW_AT_name
.uleb128 8 # DW_FORM_string
.uleb128 0x2131 # DW_AT_GNU_dwo_id
.uleb128 7 # DW_FORM_data8
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 0 # EOM(3)
.LAbbrEnd:
.section .debug_info.dwo, "e", @progbits
.LCUBegin:
.long .LCUEnd-.LCUVersion # Length
.LCUVersion:
.short 4 # Version
.long 0 # Abbrev offset
.byte 4 # Address size
.uleb128 1 # Abbrev [1] DW_TAG_compile_unit
.asciz "a.c" # DW_AT_name
.quad 0x1100001122222222 # DW_AT_GNU_dwo_id
.LCUEnd:
.section .debug_cu_index, "", @progbits
## Header:
.short 2 # Version
.space 2 # Padding
.long 2 # Section count
.long 1 # Unit count
.long 4 # Slot count
## Hash Table of Signatures:
.quad 0
.quad 0
.quad 0x1100001122222222
.quad 0
## Parallel Table of Indexes:
.long 0
.long 0
.long 1
.long 0
## Table of Section Offsets:
## Row 0:
.long 1 # DW_SECT_INFO
.long 3 # DW_SECT_ABBREV
## Row 1:
.long .LCUBegin-.debug_info.dwo # Offset in .debug_info.dwo
.long .LAbbrBegin-.debug_abbrev.dwo # Offset in .debug_abbrev.dwo
## Table of Section Sizes:
.long .LCUEnd-.LCUBegin-1 # Size of the contribution in .debug_info.dwo (invalid)
.long .LAbbrEnd-.LAbbrBegin