[llvm] [llvm-objdump] Error with relevant message when adding invalid notes (PR #90458)
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Tue May 21 00:55:39 PDT 2024
https://github.com/serge-sans-paille updated https://github.com/llvm/llvm-project/pull/90458
>From 2f2a5be3bcc4a0eef8305e9e4fdade92bf2102f9 Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguelton at mozilla.com>
Date: Mon, 29 Apr 2024 13:27:04 +0200
Subject: [PATCH] [llvm-objdump] Error with relevant message when adding
invalid notes
Also add a --no-verify-note-sections flag to make it possible to add
invalid sections if needs be.
---
llvm/include/llvm/ObjCopy/CommonConfig.h | 1 +
llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp | 71 +++++++++++++++++--
.../llvm-objcopy/ELF/add-invalid-note.test | 34 +++++++++
llvm/tools/llvm-objcopy/ObjcopyOptions.cpp | 2 +
llvm/tools/llvm-objcopy/ObjcopyOpts.td | 3 +
5 files changed, 105 insertions(+), 6 deletions(-)
create mode 100644 llvm/test/tools/llvm-objcopy/ELF/add-invalid-note.test
diff --git a/llvm/include/llvm/ObjCopy/CommonConfig.h b/llvm/include/llvm/ObjCopy/CommonConfig.h
index ae08d4032736e..c77a286799ead 100644
--- a/llvm/include/llvm/ObjCopy/CommonConfig.h
+++ b/llvm/include/llvm/ObjCopy/CommonConfig.h
@@ -258,6 +258,7 @@ struct CommonConfig {
bool StripNonAlloc = false;
bool StripSections = false;
bool StripUnneeded = false;
+ bool VerifyNoteSections = true;
bool Weaken = false;
bool DecompressDebugSections = false;
diff --git a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
index f343d1447e055..bf36adba148e0 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
+++ b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
@@ -623,6 +623,58 @@ 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 = *reinterpret_cast<const uint32_t *>(NameSize.data());
+ uint32_t DescSizeValue = *reinterpret_cast<const uint32_t *>(DescSize.data());
+
+ if (Endianness != llvm::endianness::native) {
+ NameSizeValue = byteswap(NameSizeValue);
+ DescSizeValue = byteswap(DescSizeValue);
+ }
+ uint64_t ExpectedDataSize =
+ /*NameSize=*/4 + /*DescSize=*/4 + /*Type=*/4 +
+ /*Name=*/(NameSizeValue + 3) / 4 * 4 +
+ /*Desc=*/(DescSizeValue + 3) / 4 * 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 +683,7 @@ 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;
@@ -675,12 +727,19 @@ 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 (Config.VerifyNoteSections)
+ return verifyNoteSection(Name, E, Data);
+ }
return Error::success();
};
if (Error E = handleUserSection(AddedSection, AddSection))
@@ -813,7 +872,7 @@ 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);
}
@@ -831,7 +890,7 @@ 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);
}
@@ -850,7 +909,7 @@ 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..1cd2123782eed
--- /dev/null
+++ b/llvm/test/tools/llvm-objcopy/ELF/add-invalid-note.test
@@ -0,0 +1,34 @@
+## Verify that --add-section warns on invalid note sections.
+
+# Add [namesz, descsz, type, name, desc] for a build id.
+#
+# RUN: echo -e -n "\x04\x00\x00\x00" > %t-miss-padding-note.bin
+# RUN: echo -e -n "\x07\x00\x00\x00" >> %t-miss-padding-note.bin
+# RUN: echo -e -n "\x03\x00\x00\x00" >> %t-miss-padding-note.bin
+# RUN: echo -e -n "GNU\x00" >> %t-miss-padding-note.bin
+# RUN: echo -e -n "\x0c\x0d\x0e" >> %t-miss-padding-note.bin
+#
+# RUN: echo -e -n "\x08\x00\x00\x00" > %t-invalid-size-note.bin
+# RUN: echo -e -n "\x07\x00\x00\x00" >> %t-invalid-size-note.bin
+# RUN: echo -e -n "\x03\x00\x00\x00" >> %t-invalid-size-note.bin
+# RUN: echo -e -n "GNU\x00" >> %t-invalid-size-note.bin
+# RUN: echo -e -n "\x0c\x0d\x0e\x00" >> %t-invalid-size-note.bin
+
+# RUN: echo -e -n "\x08\x00\x00\x00" > %t-short-note.bin
+# RUN: echo -e -n "\x07\x00\x00\x00" >> %t-short-note.bin
+
+# RUN: yaml2obj %s -o %t.o
+# 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
+# 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
+# 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
+# RUN: llvm-objcopy --add-section=.note.short=%t-short-note.bin --no-verify-note-sections %t.o %t-with-note.o
+
+!ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_REL
+
+# CHECK-MISS-PADDING: .note.miss.padding data size must be a multiple of 4 bytes
+# CHECK-INVALID-SIZE: .note.invalid.size data size is incompatible with the content of the name and description size fields: expecting 28, found 20
+# CHECK-SHORT: .note.short data must be either empty or at least 12 bytes long
diff --git a/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp b/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
index a1897334cff2e..8990bffc0d66b 100644
--- a/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
+++ b/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
@@ -943,6 +943,8 @@ objcopy::parseObjcopyOptions(ArrayRef<const char *> RawArgsArr,
? DiscardType::All
: DiscardType::Locals;
}
+ Config.VerifyNoteSections =
+ !InputArgs.hasArg(OBJCOPY_no_verify_note_sections);
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 4bc80eba05f8e..1db80e0f2c4e8 100644
--- a/llvm/tools/llvm-objcopy/ObjcopyOpts.td
+++ b/llvm/tools/llvm-objcopy/ObjcopyOpts.td
@@ -176,6 +176,9 @@ def G : JoinedOrSeparate<["-"], "G">,
Alias<keep_global_symbol>,
HelpText<"Alias for --keep-global-symbol">;
+def no_verify_note_sections : Flag<["--"], "no-verify-note-sections">,
+ HelpText<"Disable note section validation">;
+
defm keep_global_symbols
: Eq<"keep-global-symbols",
"Read a list of symbols from <filename> and run as if "
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