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[DWARF v5] Verifier: Add checks for DW_FORM_strx* forms.
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Adding functionality to the DWARF verifier for DWARF v5 strx* forms which 
index into the string offsets table.

Differential Revision: https://reviews.llvm.org/D54049

llvm-svn: 346061
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@wolfy1961
wolfy1961 committed Nov 3, 2018
1 parent 75c16d8 commit 5253ccc
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Showing 4 changed files with 156 additions and 6 deletions.
39 changes: 39 additions & 0 deletions llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
View file
Expand Up @@ -611,6 +611,45 @@ unsigned DWARFVerifier::verifyDebugInfoForm(const DWARFDie &Die,
}
break;
}
case DW_FORM_strx:
case DW_FORM_strx1:
case DW_FORM_strx2:
case DW_FORM_strx3:
case DW_FORM_strx4: {
auto Index = AttrValue.Value.getRawUValue();
auto DieCU = Die.getDwarfUnit();
// Check that we have a valid DWARF v5 string offsets table.
if (!DieCU->getStringOffsetsTableContribution()) {
++NumErrors;
error() << FormEncodingString(Form)
<< " used without a valid string offsets table:\n";
dump(Die) << '\n';
break;
}
// Check that the index is within the bounds of the section.
unsigned ItemSize = DieCU->getDwarfStringOffsetsByteSize();
// Use a 64-bit type to calculate the offset to guard against overflow.
uint64_t Offset =
(uint64_t)DieCU->getStringOffsetsBase() + Index * ItemSize;
if (DObj.getStringOffsetSection().Data.size() < Offset + ItemSize) {
++NumErrors;
error() << FormEncodingString(Form) << " uses index "
<< format("%" PRIu64, Index) << ", which is too large:\n";
dump(Die) << '\n';
break;
}
// Check that the string offset is valid.
uint64_t StringOffset = *DieCU->getStringOffsetSectionItem(Index);
if (StringOffset >= DObj.getStringSection().size()) {
++NumErrors;
error() << FormEncodingString(Form) << " uses index "
<< format("%" PRIu64, Index)
<< ", but the referenced string"
" offset is beyond .debug_str bounds:\n";
dump(Die) << '\n';
}
break;
}
default:
break;
}
Expand Down
31 changes: 27 additions & 4 deletions llvm/test/DebugInfo/X86/dwarfdump-str-offsets.s
View file
@@ -1,5 +1,6 @@
# RUN: llvm-mc -triple x86_64-unknown-linux %s -filetype=obj -o %t.o
# RUN: llvm-dwarfdump -v %t.o 2> %t.err | FileCheck --check-prefix=COMMON --check-prefix=SPLIT %s
# RUN: llvm-dwarfdump -verify %t.o | FileCheck --check-prefix=VERIFY %s
#
# Check that we don't report an error on a non-existent range list table.
# RUN: FileCheck -allow-empty --check-prefix ERR %s < %t.err
Expand Down Expand Up @@ -136,20 +137,33 @@ dwo_str_TU_5_type:
.byte 0x00 # DW_CHILDREN_no
.byte 0x03 # DW_AT_name
.byte 0x26 # DW_FORM_strx2
.byte 0x49 # DW_AT_type
.byte 0x13 # DW_FORM_ref4
.byte 0x00 # EOM(1)
.byte 0x00 # EOM(2)
.byte 0x06 # Abbrev code
.byte 0x34 # DW_TAG_variable
.byte 0x00 # DW_CHILDREN_no
.byte 0x03 # DW_AT_name
.byte 0x27 # DW_FORM_strx3
.byte 0x49 # DW_AT_type
.byte 0x13 # DW_FORM_ref4
.byte 0x00 # EOM(1)
.byte 0x00 # EOM(2)
.byte 0x07 # Abbrev code
.byte 0x34 # DW_TAG_variable
.byte 0x00 # DW_CHILDREN_no
.byte 0x03 # DW_AT_name
.byte 0x28 # DW_FORM_strx4
.byte 0x49 # DW_AT_type
.byte 0x13 # DW_FORM_ref4
.byte 0x00 # EOM(1)
.byte 0x00 # EOM(2)
.byte 0x08 # Abbrev code
.byte 0x24 # DW_TAG_base_type
.byte 0x00 # DW_CHILDREN_no
.byte 0x3e # DW_AT_encoding
.byte 0x0b # DW_FORM_data1
.byte 0x00 # EOM(1)
.byte 0x00 # EOM(2)
.byte 0x00 # EOM(3)
Expand Down Expand Up @@ -202,17 +216,24 @@ CU1_5_version:
# A subprogram DIE with DW_AT_name, using DW_FORM_strx1.
.byte 4 # Abbreviation code
.byte 3 # Subprogram name string (DW_FORM_strx1)
# A variable DIE with DW_AT_name, using DW_FORM_strx2.
# A variable DIE with DW_AT_name, using DW_FORM_strx2, and DW_AT_type.
.byte 5 # Abbreviation code
.short 0x0004 # Subprogram name string (DW_FORM_strx2)
# A variable DIE with DW_AT_name, using DW_FORM_strx3.
.long TypeDie-.debug_info
# A variable DIE with DW_AT_name, using DW_FORM_strx3, and DW_AT_type.
.byte 6 # Abbreviation code
.byte 5 # Subprogram name string (DW_FORM_strx3)
.short 0 # Subprogram name string (DW_FORM_strx3)
# A variable DIE with DW_AT_name, using DW_FORM_strx4.
.long TypeDie-.debug_info
# A variable DIE with DW_AT_name, using DW_FORM_strx4, and DW_AT_type.
.byte 7 # Abbreviation code
.quad 0x00000006 # Subprogram name string (DW_FORM_strx4)
.long 6 # Subprogram name string (DW_FORM_strx4)
.long TypeDie-.debug_info
.byte 0 # NULL
# A base type DIE with DW_AT_encoding.
TypeDie:
.byte 8 # Abbreviation code
.byte 5 # DW_ATE_signed
.byte 0 # NULL
.byte 0 # NULL
CU1_5_end:
Expand Down Expand Up @@ -386,4 +407,6 @@ TU_split_5_end:
# SPLIT-NEXT: 0x00000014: 00000047 "V5_split_type_unit"
# SPLIT-NEXT: 0x00000018: 0000005a "V5_split_Mystruct"

# VERIFY: No errors.

# ERR-NOT: parsing a range list table:
4 changes: 2 additions & 2 deletions llvm/test/tools/llvm-dwarfdump/X86/verify_debug_info.s
View file
Expand Up @@ -7,7 +7,7 @@
# CHECK-NEXT: DW_AT_producer [DW_FORM_strp] ( .debug_str[0x00000000] = "clang version 5.0.0 (trunk 308185) (llvm/trunk 308186)")
# CHECK-NEXT: DW_AT_language [DW_FORM_data2] (DW_LANG_C99)
# CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x00000037] = "basic.c")
# CHECK-NEXT: DW_AT_stmt_list [DW_FORM_strx4] ( indexed (00000000) string = )
# CHECK-NEXT: DW_AT_stmt_list [DW_FORM_block4]
# CHECK-NEXT: DW_AT_comp_dir [DW_FORM_strp] ( .debug_str[0x0000003f] = "/Users/sgravani/Development/tests")
# CHECK-NEXT: DW_AT_low_pc [DW_FORM_addr] (0x0000000000000000)
# CHECK-NEXT: DW_AT_high_pc [DW_FORM_data4] (0x00000016){{[[:space:]]}}
Expand Down Expand Up @@ -82,7 +82,7 @@ Lsection_abbrev:
.byte 3 ## DW_AT_name
.byte 14 ## DW_FORM_strp
.byte 16 ## DW_AT_stmt_list
.byte 40 ## DW_FORM_sec_offset -- error: DIE has invalid DW_AT_stmt_list encoding:
.byte 4 ## DW_FORM_sec_offset -- error: DIE has invalid DW_AT_stmt_list encoding:
.byte 27 ## DW_AT_comp_dir
.byte 14 ## DW_FORM_strp
.byte 17 ## DW_AT_low_pc
Expand Down
88 changes: 88 additions & 0 deletions llvm/test/tools/llvm-dwarfdump/X86/verify_strings.s
View file
@@ -0,0 +1,88 @@
# RUN: llvm-mc -triple x86_64-unknown-linux %s -filetype=obj -o %t.o
# RUN: not llvm-dwarfdump -verify %t.o | FileCheck --check-prefix=VERIFY %s

# Check that the verifier correctly diagnoses various error conditions with
# the usage of string indices and string offsets tables.

.section .debug_str,"MS",@progbits,1
str_producer:
.asciz "Handmade DWARF producer"

.section .debug_str_offsets,"",@progbits
# The string offsets table
.long .debug_str_offsets_segment0_end-.debug_str_offsets_base0+4
.short 5 # DWARF version
.short 0 # Padding
.debug_str_offsets_base0:
.long str_producer
.long 1000 # Invalid string address.
.debug_str_offsets_segment0_end:

# A simple abbrev section with a basic compile unit DIE.
.section .debug_abbrev,"",@progbits
.byte 0x01 # Abbrev code
.byte 0x11 # DW_TAG_compile_unit
.byte 0x01 # DW_CHILDREN_no
.byte 0x25 # DW_AT_producer
.byte 0x1a # DW_FORM_strx
.byte 0x72 # DW_AT_str_offsets_base
.byte 0x17 # DW_FORM_sec_offset
.byte 0x00 # EOM(1)
.byte 0x00 # EOM(2)

.section .debug_info,"",@progbits

# The first unit's CU DIE has an invalid DW_AT_str_offsets_base which
# renders any string index unresolvable.

# DWARF v5 CU header.
.long CU1_5_end-CU1_5_version # Length of Unit
CU1_5_version:
.short 5 # DWARF version number
.byte 1 # DWARF Unit Type
.byte 8 # Address Size (in bytes)
.long .debug_abbrev # Offset Into Abbrev. Section
# The compile-unit DIE, which has DW_AT_producer and DW_AT_str_offsets.
.byte 1 # Abbreviation code
.byte 0 # Index of string for DW_AT_producer.
.long 1000 # Bad value for DW_AT_str_offsets_base
.byte 0 # NULL
CU1_5_end:

# The second unit's CU DIE uses an invalid string index.

# DWARF v5 CU header
.long CU2_5_end-CU2_5_version # Length of Unit
CU2_5_version:
.short 5 # DWARF version number
.byte 1 # DWARF Unit Type
.byte 8 # Address Size (in bytes)
.long .debug_abbrev # Offset Into Abbrev. Section
# The compile-unit DIE, which has DW_AT_producer and DW_AT_str_offsets.
.byte 1 # Abbreviation code
.byte 100 # Invalid string index
.long .debug_str_offsets_base0
.byte 0 # NULL
CU2_5_end:

# The third unit's CU DIE uses a valid string index but the entry in the
# string offsets table is invalid.

# DWARF v5 CU header
.long CU3_5_end-CU3_5_version # Length of Unit
CU3_5_version:
.short 5 # DWARF version number
.byte 1 # DWARF Unit Type
.byte 8 # Address Size (in bytes)
.long .debug_abbrev # Offset Into Abbrev. Section
# The compile-unit DIE, which has DW_AT_producer and DW_AT_str_offsets.
.byte 1 # Abbreviation code
.byte 1 # Index of string for DW_AT_producer.
.long .debug_str_offsets_base0
.byte 0 # NULL
CU3_5_end:

# VERIFY-DAG: error: DW_FORM_strx used without a valid string offsets table:
# VERIFY-DAG: error: DW_FORM_strx uses index 100, which is too large:
# VERIFY-DAG: error: DW_FORM_strx uses index 1, but the referenced string offset
# VERIFY-DAG-SAME: is beyond .debug_str bounds:

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