Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Support java class files #142

Open
wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Support java class files #142

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
Binary file added fixtures/sample.class
View file
Open in desktop
Binary file not shown.
2 changes: 2 additions & 0 deletions match_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,7 @@ func TestMatchFile(t *testing.T) {
{"zst"},
{"exr"},
{"avif"},
{"class"},
}

for _, test := range cases {
Expand All @@ -77,6 +78,7 @@ func TestMatchReader(t *testing.T) {
{bytes.NewBuffer([]byte{0xFF, 0xD8, 0xFF}), "jpg"},
{bytes.NewBuffer([]byte{0xFF, 0xD8, 0x00}), "unknown"},
{bytes.NewBuffer([]byte{0x89, 0x50, 0x4E, 0x47}), "png"},
{bytes.NewBuffer([]byte{0xCA, 0xFE, 0xBA, 0xBE, 0x00, 0x00, 0x00, 0xff}), "class"},
}

for _, test := range cases {
Expand Down
21 changes: 20 additions & 1 deletion matchers/archive.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ var (
TypeDcm = newType("dcm", "application/dicom")
TypeIso = newType("iso", "application/x-iso9660-image")
TypeMachO = newType("macho", "application/x-mach-binary") // Mach-O binaries have no common extension.
TypeClass = newType("class", "application/java-vm") // Java class files
)

var Archive = Map{
Expand Down Expand Up @@ -67,6 +68,7 @@ var Archive = Map{
TypeDcm: Dcm,
TypeIso: Iso,
TypeMachO: MachO,
TypeClass: Class,
}

var (
Expand Down Expand Up @@ -184,7 +186,24 @@ func MachO(buf []byte) bool {
// Big endian versions below here...
(buf[0] == 0xCF && buf[1] == 0xFA && buf[2] == 0xED && buf[3] == 0xFE) ||
(buf[0] == 0xCE && buf[1] == 0xFA && buf[2] == 0xED && buf[3] == 0xFE) ||
(buf[0] == 0xCA && buf[1] == 0xFE && buf[2] == 0xBA && buf[3] == 0xBE))
// Java class files have a 0xCAFEBABE magic number. As the Class func can disambiguate,
// if buf has 0xCAFEBABE as a magic number but Class returns false, assume it's a MachO.
(buf[0] == 0xCA && buf[1] == 0xFE && buf[2] == 0xBA && buf[3] == 0xBE && !Class(buf)))
}

// Class matches Java class files which are pretty tricky.
// They have the same magic number as some MachO FAT files.
// Reference: https://opensource.apple.com/source/file/file-80.40.2/file/magic/Magdir/cafebabe.auto.html
func Class(buf []byte) bool {
if len(buf) < 8 {
return false
}

if !(buf[0] == 0xCA && buf[1] == 0xFE && buf[2] == 0xBA && buf[3] == 0xBE) {
return false
}

return binary.BigEndian.Uint32(buf[4:8]) >= 44 // Java 1.0 corresponds to major version 44.
}

// Zstandard compressed data is made of one or more frames.
Expand Down