[llvm] fb5a38b - [llvm-objcopy] Add verification of added .note section format
via llvm-commits
llvm-commits at lists.llvm.org
Thu Jul 11 09:01:08 PDT 2024
Author: serge-sans-paille
Date: 2024-07-11T17:59:19+02:00
New Revision: fb5a38bb4930736b0aab3ce428b60245921f982f
URL: https://github.com/llvm/llvm-project/commit/fb5a38bb4930736b0aab3ce428b60245921f982f
DIFF: https://github.com/llvm/llvm-project/commit/fb5a38bb4930736b0aab3ce428b60245921f982f.diff
LOG: [llvm-objcopy] Add verification of added .note section format
Also add a --no-verify-note-sections flag to make it possible to add
invalid sections if needs be.
Pull Request: https://github.com/llvm/llvm-project/pull/90458
Added:
llvm/test/tools/llvm-objcopy/ELF/add-invalid-note.test
Modified:
llvm/docs/CommandGuide/llvm-objcopy.rst
llvm/docs/ReleaseNotes.rst
llvm/include/llvm/ObjCopy/ELF/ELFConfig.h
llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
llvm/tools/llvm-objcopy/ObjcopyOpts.td
Removed:
################################################################################
diff --git a/llvm/docs/CommandGuide/llvm-objcopy.rst b/llvm/docs/CommandGuide/llvm-objcopy.rst
index eaeb19e26c7b6..8ccb025a3f0f3 100644
--- a/llvm/docs/CommandGuide/llvm-objcopy.rst
+++ b/llvm/docs/CommandGuide/llvm-objcopy.rst
@@ -426,6 +426,10 @@ them.
The default is `default`.
+.. option:: --no-verify-note-sections
+
+ When adding note sections, do not verify if the section format is valid.
+
.. option:: --output-target <format>, -O
Write the output as the specified format. See `SUPPORTED FORMATS`_ for a list
@@ -516,6 +520,11 @@ them.
specified format. See `SUPPORTED FORMATS`_ for a list of valid ``<format>``
values.
+.. option:: --verify-note-sections
+
+ When adding note sections, verify if the section format is valid. On by
+ default.
+
.. option:: --weaken-symbol <symbol>, -W
Mark global symbols named ``<symbol>`` as weak symbols in the output. Can
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 1c2ada2173c9c..4b8f7f20b5118 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -379,6 +379,10 @@ Changes to the LLVM tools
jumping in reverse direction with shift+L/R/B). (`#95662
<https://github.com/llvm/llvm-project/pull/95662>`_).
+* llvm-objcopy now verifies format of ``.note`` sections for ELF input. This can
+ be disabled by ``--no-verify-note-sections``. (`#90458
+ <https://github.com/llvm/llvm-project/pull/90458>`).
+
Changes to LLDB
---------------------------------
diff --git a/llvm/include/llvm/ObjCopy/ELF/ELFConfig.h b/llvm/include/llvm/ObjCopy/ELF/ELFConfig.h
index eafed92516c7d..59960b6530743 100644
--- a/llvm/include/llvm/ObjCopy/ELF/ELFConfig.h
+++ b/llvm/include/llvm/ObjCopy/ELF/ELFConfig.h
@@ -30,6 +30,7 @@ struct ELFConfig {
bool AllowBrokenLinks = false;
bool KeepFileSymbols = false;
bool LocalizeHidden = false;
+ bool VerifyNoteSections = true;
};
} // namespace objcopy
diff --git a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
index 60a85f9a49c59..075455c034154 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
+++ b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
@@ -623,6 +623,54 @@ handleUserSection(const NewSectionInfo &NewSection,
return F(NewSection.SectionName, Data);
}
+static Error verifyNoteSection(StringRef Name, endianness Endianness,
+ ArrayRef<uint8_t> Data) {
+ // An ELF note has the following structure:
+ // Name Size: 4 bytes (integer)
+ // Desc Size: 4 bytes (integer)
+ // Type : 4 bytes
+ // Name : variable size, padded to a 4 byte boundary
+ // Desc : variable size, padded to a 4 byte boundary
+
+ if (Data.empty())
+ return Error::success();
+
+ if (Data.size() < 12) {
+ std::string msg;
+ raw_string_ostream(msg)
+ << Name << " data must be either empty or at least 12 bytes long";
+ return createStringError(errc::invalid_argument, msg);
+ }
+ if (Data.size() % 4 != 0) {
+ std::string msg;
+ raw_string_ostream(msg)
+ << Name << " data size must be a multiple of 4 bytes";
+ return createStringError(errc::invalid_argument, msg);
+ }
+ ArrayRef<uint8_t> NameSize = Data.slice(0, 4);
+ ArrayRef<uint8_t> DescSize = Data.slice(4, 4);
+
+ uint32_t NameSizeValue = support::endian::read32(NameSize.data(), Endianness);
+ uint32_t DescSizeValue = support::endian::read32(DescSize.data(), Endianness);
+
+ uint64_t ExpectedDataSize =
+ /*NameSize=*/4 + /*DescSize=*/4 + /*Type=*/4 +
+ /*Name=*/alignTo(NameSizeValue, 4) +
+ /*Desc=*/alignTo(DescSizeValue, 4);
+ uint64_t ActualDataSize = Data.size();
+ if (ActualDataSize != ExpectedDataSize) {
+ std::string msg;
+ raw_string_ostream(msg)
+ << Name
+ << " data size is incompatible with the content of "
+ "the name and description size fields:"
+ << " expecting " << ExpectedDataSize << ", found " << ActualDataSize;
+ return createStringError(errc::invalid_argument, msg);
+ }
+
+ return Error::success();
+}
+
// This function handles the high level operations of GNU objcopy including
// handling command line options. It's important to outline certain properties
// we expect to hold of the command line operations. Any operation that "keeps"
@@ -631,7 +679,7 @@ handleUserSection(const NewSectionInfo &NewSection,
// depend a) on the order the options occur in or b) on some opaque priority
// system. The only priority is that keeps/copies overrule removes.
static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig,
- Object &Obj) {
+ ElfType OutputElfType, Object &Obj) {
if (Config.OutputArch) {
Obj.Machine = Config.OutputArch->EMachine;
Obj.OSABI = Config.OutputArch->OSABI;
@@ -702,12 +750,19 @@ static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig,
if (Sec.Flags & SHF_ALLOC && Sec.Type != SHT_NOTE)
Sec.Type = SHT_NOBITS;
+ endianness E = OutputElfType == ELFT_ELF32LE || OutputElfType == ELFT_ELF64LE
+ ? endianness::little
+ : endianness::big;
+
for (const NewSectionInfo &AddedSection : Config.AddSection) {
- auto AddSection = [&](StringRef Name, ArrayRef<uint8_t> Data) {
+ auto AddSection = [&](StringRef Name, ArrayRef<uint8_t> Data) -> Error {
OwnedDataSection &NewSection =
Obj.addSection<OwnedDataSection>(Name, Data);
- if (Name.starts_with(".note") && Name != ".note.GNU-stack")
+ if (Name.starts_with(".note") && Name != ".note.GNU-stack") {
NewSection.Type = SHT_NOTE;
+ if (ELFConfig.VerifyNoteSections)
+ return verifyNoteSection(Name, E, Data);
+ }
return Error::success();
};
if (Error E = handleUserSection(AddedSection, AddSection))
@@ -840,7 +895,7 @@ Error objcopy::elf::executeObjcopyOnIHex(const CommonConfig &Config,
const ElfType OutputElfType =
getOutputElfType(Config.OutputArch.value_or(MachineInfo()));
- if (Error E = handleArgs(Config, ELFConfig, **Obj))
+ if (Error E = handleArgs(Config, ELFConfig, OutputElfType, **Obj))
return E;
return writeOutput(Config, **Obj, Out, OutputElfType);
}
@@ -858,7 +913,7 @@ Error objcopy::elf::executeObjcopyOnRawBinary(const CommonConfig &Config,
// (-B<arch>).
const ElfType OutputElfType =
getOutputElfType(Config.OutputArch.value_or(MachineInfo()));
- if (Error E = handleArgs(Config, ELFConfig, **Obj))
+ if (Error E = handleArgs(Config, ELFConfig, OutputElfType, **Obj))
return E;
return writeOutput(Config, **Obj, Out, OutputElfType);
}
@@ -877,7 +932,7 @@ Error objcopy::elf::executeObjcopyOnBinary(const CommonConfig &Config,
? getOutputElfType(*Config.OutputArch)
: getOutputElfType(In);
- if (Error E = handleArgs(Config, ELFConfig, **Obj))
+ if (Error E = handleArgs(Config, ELFConfig, OutputElfType, **Obj))
return createFileError(Config.InputFilename, std::move(E));
if (Error E = writeOutput(Config, **Obj, Out, OutputElfType))
diff --git a/llvm/test/tools/llvm-objcopy/ELF/add-invalid-note.test b/llvm/test/tools/llvm-objcopy/ELF/add-invalid-note.test
new file mode 100644
index 0000000000000..9a28bbb9aa308
--- /dev/null
+++ b/llvm/test/tools/llvm-objcopy/ELF/add-invalid-note.test
@@ -0,0 +1,54 @@
+## Verify that --add-section warns on invalid note sections.
+
+## Add [namesz, descsz, type, name, desc] for a build id.
+
+## Notes should be padded to 8 bytes.
+# RUN: printf "\x04\x00\x00\x00" > %t-miss-padding-note.bin
+# RUN: printf "\x07\x00\x00\x00" >> %t-miss-padding-note.bin
+# RUN: printf "\x03\x00\x00\x00" >> %t-miss-padding-note.bin
+# RUN: printf "GNU\x00" >> %t-miss-padding-note.bin
+# RUN: printf "\x0c\x0d\x0e" >> %t-miss-padding-note.bin
+
+## The namesz field bit is incorrect.
+# RUN: printf "\x08\x00\x00\x00" > %t-invalid-size-note.bin
+# RUN: printf "\x07\x00\x00\x00" >> %t-invalid-size-note.bin
+# RUN: printf "\x03\x00\x00\x00" >> %t-invalid-size-note.bin
+# RUN: printf "GNU\x00" >> %t-invalid-size-note.bin
+# RUN: printf "\x0c\x0d\x0e\x00" >> %t-invalid-size-note.bin
+
+## Missing type field.
+# RUN: printf "\x08\x00\x00\x00" > %t-short-note.bin
+# RUN: printf "\x07\x00\x00\x00" >> %t-short-note.bin
+
+# RUN: yaml2obj %s -o %t.o
+
+## Test each invalid note.
+# RUN: not llvm-objcopy --add-section=.note.miss.padding=%t-miss-padding-note.bin %t.o %t-with-note.o 2>&1 | FileCheck --check-prefix=CHECK-MISS-PADDING %s
+# CHECK-MISS-PADDING: .note.miss.padding data size must be a multiple of 4 bytes
+
+# RUN: not llvm-objcopy --add-section=.note.invalid.size=%t-invalid-size-note.bin %t.o %t-with-note.o 2>&1 | FileCheck --check-prefix=CHECK-INVALID-SIZE %s
+# CHECK-INVALID-SIZE: .note.invalid.size data size is incompatible with the content of the name and description size fields: expecting 28, found 20
+
+# RUN: not llvm-objcopy --add-section=.note.short=%t-short-note.bin %t.o %t-with-note.o 2>&1 | FileCheck --check-prefix=CHECK-SHORT %s
+# CHECK-SHORT: .note.short data must be either empty or at least 12 bytes long
+
+## Test compatibility with .note.gnu.property, which has 8-byte alignment.
+# RUN: printf "\x04\x00\x00\x00\x40\x00\x00\x00\x05\x00\x00\x00\x47\x4e\x55\x00" > %t-note-gnu-property.bin
+# RUN: printf "\x02\x00\x00\xc0\x04\x00\x00\x00\x03\x00\x00\x00\x00\x00\x00\x00" >> %t-note-gnu-property.bin
+# RUN: printf "\x01\x80\x01\xc0\x04\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00" >> %t-note-gnu-property.bin
+# RUN: printf "\x01\x00\x01\xc0\x04\x00\x00\x00\x0b\x00\x00\x00\x00\x00\x00\x00" >> %t-note-gnu-property.bin
+# RUN: printf "\x02\x00\x01\xc0\x04\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00" >> %t-note-gnu-property.bin
+# RUN: llvm-objcopy --add-section=.note.gnu.property=%t-note-gnu-property.bin %t.o %t-with-note-gnu-property.o
+
+## Test that verification can be disabled.
+# RUN: llvm-objcopy --add-section=.note.short=%t-short-note.bin --no-verify-note-sections %t.o %t-with-note.o
+
+## Test that last argument has precedence.
+# RUN: llvm-objcopy --add-section=.note.short=%t-short-note.bin --verify-note-sections --no-verify-note-sections %t.o %t-with-note.o
+# RUN: not llvm-objcopy --add-section=.note.short=%t-short-note.bin --no-verify-note-sections --verify-note-sections %t.o %t-with-note.o 2>&1 | FileCheck --check-prefix=CHECK-SHORT %s
+
+!ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_REL
diff --git a/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp b/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
index eb27ba05fbb73..a54feb7644bda 100644
--- a/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
+++ b/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
@@ -990,6 +990,10 @@ objcopy::parseObjcopyOptions(ArrayRef<const char *> RawArgsArr,
? DiscardType::All
: DiscardType::Locals;
}
+
+ ELFConfig.VerifyNoteSections = InputArgs.hasFlag(
+ OBJCOPY_verify_note_sections, OBJCOPY_no_verify_note_sections, true);
+
Config.OnlyKeepDebug = InputArgs.hasArg(OBJCOPY_only_keep_debug);
ELFConfig.KeepFileSymbols = InputArgs.hasArg(OBJCOPY_keep_file_symbols);
MachOConfig.KeepUndefined = InputArgs.hasArg(OBJCOPY_keep_undefined);
diff --git a/llvm/tools/llvm-objcopy/ObjcopyOpts.td b/llvm/tools/llvm-objcopy/ObjcopyOpts.td
index f3d14abee43bd..b26c497ca3997 100644
--- a/llvm/tools/llvm-objcopy/ObjcopyOpts.td
+++ b/llvm/tools/llvm-objcopy/ObjcopyOpts.td
@@ -1,5 +1,10 @@
include "CommonOpts.td"
+multiclass B<string name, string help1, string help2> {
+ def NAME: Flag<["--"], name>, HelpText<help1>;
+ def no_ # NAME: Flag<["--"], "no-" # name>, HelpText<help2>;
+}
+
defm binary_architecture
: Eq<"binary-architecture", "Ignored for compatibility">;
def B : JoinedOrSeparate<["-"], "B">,
@@ -176,6 +181,10 @@ def G : JoinedOrSeparate<["-"], "G">,
Alias<keep_global_symbol>,
HelpText<"Alias for --keep-global-symbol">;
+defm verify_note_sections : B<"verify-note-sections",
+ "Validate note sections",
+ "Don't validate note sections">;
+
defm keep_global_symbols
: Eq<"keep-global-symbols",
"Read a list of symbols from <filename> and run as if "
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