symbols_map: allow unexpected EOF in ELF files am: 338df53621 am: b9f5de22b8

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2061530

Change-Id: I6dd3c5cfddf00cb3539e688a0e9682fb9d3c7e42
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

2 files changed, 42 insertions, 3 deletions

diff --git a/cmd/symbols_map/elf.go b/cmd/symbols_map/elf.go
index 3c8b1e42b..950e3b246 100644
--- a/cmd/symbols_map/elf.go
+++ b/cmd/symbols_map/elf.go
@@ -38,13 +38,13 @@ func elfIdentifier(filename string, allowMissing bool) (string, error) {
 	return elfIdentifierFromReaderAt(f, filename, allowMissing)
 }
 
-// elfIdentifier extracts the elf build ID from a ReaderAt.  If allowMissing is true it returns
-// an empty identifier if the file exists but the build ID note does not.
+// elfIdentifierFromReaderAt extracts the elf build ID from a ReaderAt.  If allowMissing is true it
+// returns an empty identifier if the file exists but the build ID note does not.
 func elfIdentifierFromReaderAt(r io.ReaderAt, filename string, allowMissing bool) (string, error) {
 	f, err := elf.NewFile(r)
 	if err != nil {
 		if allowMissing {
-			if errors.Is(err, io.EOF) {
+			if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {
 				return "", nil
 			}
 			if _, ok := err.(*elf.FormatError); ok {
diff --git a/cmd/symbols_map/elf_test.go b/cmd/symbols_map/elf_test.go
index b96ea592c..a94c87f21 100644
--- a/cmd/symbols_map/elf_test.go
+++ b/cmd/symbols_map/elf_test.go
@@ -39,6 +39,10 @@ func Test_elfIdentifierFromReaderAt_BadElfFile(t *testing.T) {
 			name:     "empty elf",
 			contents: emptyElfFile(),
 		},
+		{
+			name:     "short section header",
+			contents: shortSectionHeaderElfFile(),
+		},
 	}
 
 	for _, tt := range tests {
@@ -111,3 +115,38 @@ func emptyElfFile() string {
 	binary.Write(buf, binary.LittleEndian, header)
 	return buf.String()
 }
+
+// shortSectionHeader returns an elf file header with a section header that extends past the end of
+// the file.
+func shortSectionHeaderElfFile() string {
+	ident := [elf.EI_NIDENT]byte{}
+	identBuf := bytes.NewBuffer(ident[0:0:elf.EI_NIDENT])
+	binary.Write(identBuf, binary.LittleEndian, []byte("\x7fELF"))
+	binary.Write(identBuf, binary.LittleEndian, elf.ELFCLASS64)
+	binary.Write(identBuf, binary.LittleEndian, elf.ELFDATA2LSB)
+	binary.Write(identBuf, binary.LittleEndian, elf.EV_CURRENT)
+	binary.Write(identBuf, binary.LittleEndian, elf.ELFOSABI_LINUX)
+	binary.Write(identBuf, binary.LittleEndian, make([]byte, 8))
+
+	header := elf.Header64{
+		Ident:     ident,
+		Type:      uint16(elf.ET_EXEC),
+		Machine:   uint16(elf.EM_X86_64),
+		Version:   uint32(elf.EV_CURRENT),
+		Entry:     0,
+		Phoff:     uint64(binary.Size(elf.Header64{})),
+		Shoff:     uint64(binary.Size(elf.Header64{})),
+		Flags:     0,
+		Ehsize:    uint16(binary.Size(elf.Header64{})),
+		Phentsize: 0x38,
+		Phnum:     0,
+		Shentsize: 0x40,
+		Shnum:     1,
+		Shstrndx:  0,
+	}
+
+	buf := &bytes.Buffer{}
+	binary.Write(buf, binary.LittleEndian, header)
+	binary.Write(buf, binary.LittleEndian, []byte{0})
+	return buf.String()
+}