llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-lldb Author: Pavel Labath (labath) <details> <summary>Changes</summary> We currently cannot represent abbreviation codes with more than 16 bits, and we were lldb-asserting if we ever ran into one. While I haven't seen any real DWARF with these kinds of abbreviations, it is possible to hit this with handcrafted evil dwarf, due some sort of corruptions, or just bugs (the addition of PeekDIEName makes these bugs more likely, as the function blindly dereferences offsets within the debug info section) . Missing abbreviations were already reporting an error. This patch turns sure that large abbreviations into an error as well, and adds a test for both cases. --- Full diff: https://github.com/llvm/llvm-project/pull/93006.diff 2 Files Affected: - (modified) lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp (+16-18) - (added) lldb/test/Shell/SymbolFile/DWARF/x86/invalid_abbreviation.s (+47) ``````````diff diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp index 1b0fefedf9836..4357ccb2f5c9f 100644 --- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp +++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp @@ -11,6 +11,7 @@ #include <cassert> #include <algorithm> +#include <limits> #include <optional> #include "llvm/Support/LEB128.h" @@ -44,10 +45,20 @@ bool DWARFDebugInfoEntry::Extract(const DWARFDataExtractor &data, const DWARFUnit *cu, lldb::offset_t *offset_ptr) { m_offset = *offset_ptr; + auto report_error = [&](const char *fmt, const auto &...vals) { + cu->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError( + "[{0:x16}]: {1}, please file a bug and " + "attach the file at the start of this error message", + static_cast<uint64_t>(m_offset), llvm::formatv(fmt, vals...)); + *offset_ptr = std::numeric_limits<lldb::offset_t>::max(); + return false; + }; + m_parent_idx = 0; m_sibling_idx = 0; const uint64_t abbr_idx = data.GetULEB128(offset_ptr); - lldbassert(abbr_idx <= UINT16_MAX); + if (abbr_idx > std::numeric_limits<uint16_t>::max()) + return report_error("abbreviation code {0} too big", abbr_idx); m_abbr_idx = abbr_idx; if (m_abbr_idx == 0) { @@ -57,16 +68,9 @@ bool DWARFDebugInfoEntry::Extract(const DWARFDataExtractor &data, } const auto *abbrevDecl = GetAbbreviationDeclarationPtr(cu); - if (abbrevDecl == nullptr) { - cu->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError( - "[{0:x16}]: invalid abbreviation code {1}, " - "please file a bug and " - "attach the file at the start of this error message", - (uint64_t)m_offset, (unsigned)abbr_idx); - // WE can't parse anymore if the DWARF is borked... - *offset_ptr = UINT32_MAX; - return false; - } + if (abbrevDecl == nullptr) + return report_error("invalid abbreviation code {0}", abbr_idx); + m_tag = abbrevDecl->getTag(); m_has_children = abbrevDecl->hasChildren(); // Skip all data in the .debug_info or .debug_types for the attributes @@ -74,13 +78,7 @@ bool DWARFDebugInfoEntry::Extract(const DWARFDataExtractor &data, if (DWARFFormValue::SkipValue(attribute.Form, data, offset_ptr, cu)) continue; - cu->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError( - "[{0:x16}]: Unsupported DW_FORM_{1:x}, please file a bug " - "and " - "attach the file at the start of this error message", - (uint64_t)m_offset, (unsigned)attribute.Form); - *offset_ptr = m_offset; - return false; + return report_error("Unsupported DW_FORM_{1:x}", attribute.Form); } return true; } diff --git a/lldb/test/Shell/SymbolFile/DWARF/x86/invalid_abbreviation.s b/lldb/test/Shell/SymbolFile/DWARF/x86/invalid_abbreviation.s new file mode 100644 index 0000000000000..3f32c037aeb20 --- /dev/null +++ b/lldb/test/Shell/SymbolFile/DWARF/x86/invalid_abbreviation.s @@ -0,0 +1,47 @@ +# REQUIRES: x86 + +# RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s > %t +# RUN: %lldb %t \ +# RUN: -o exit 2>&1 | FileCheck %s + +# CHECK-DAG: error: {{.*}} [0x0000000000000022]: abbreviation code 65536 too big, please file a bug and attach the file at the start of this error message +# CHECK-DAG: error: {{.*}} [0x0000000000000048]: invalid abbreviation code 47, please file a bug and attach the file at the start of this error message + + + .section .debug_abbrev,"",@progbits + .uleb128 65535 # Largest representable Abbreviation Code + .byte 17 # DW_TAG_compile_unit + .byte 1 # DW_CHILDREN_yes + .byte 37 # DW_AT_producer + .byte 8 # DW_FORM_string + .byte 0 # EOM(1) + .byte 0 # EOM(2) + .byte 0 # EOM(3) + + .section .debug_info,"",@progbits +.Lcu_begin0: + .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit +.Ldebug_info_start0: + .short 5 # DWARF version number + .byte 1 # DWARF Unit Type + .byte 8 # Address Size (in bytes) + .long .debug_abbrev # Offset Into Abbrev. Section + .uleb128 65535 # DW_TAG_compile_unit + .asciz "Hand-written DWARF" # DW_AT_producer + .uleb128 65536 # Unrepresentable abbreviation + .byte 0 # End Of Children Mark +.Ldebug_info_end0: + + .section .debug_info,"",@progbits +.Lcu_begin1: + .long .Ldebug_info_end1-.Ldebug_info_start1 # Length of Unit +.Ldebug_info_start1: + .short 5 # DWARF version number + .byte 1 # DWARF Unit Type + .byte 8 # Address Size (in bytes) + .long .debug_abbrev # Offset Into Abbrev. Section + .uleb128 65535 # DW_TAG_compile_unit + .asciz "Hand-written DWARF" # DW_AT_producer + .byte 47 # Missing abbreviation + .byte 0 # End Of Children Mark +.Ldebug_info_end1: `````````` </details> https://github.com/llvm/llvm-project/pull/93006 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
