fairplay: Add basic SPC decoder and PSSH system id

wader · Jul 7, 2022 · 64f3e5c · 64f3e5c
1 parent 28c1a94
commit 64f3e5c
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Showing 9 changed files with 55 additions and 6 deletions.
diff --git a/README.md b/README.md
@@ -66,6 +66,7 @@ dns_tcp,
 elf,
 ether8023_frame,
 exif,
+fairplay_spc,
 flac,
 [flac_frame](doc/formats.md#flac_frame),
 flac_metadatablock,

diff --git a/doc/formats.md b/doc/formats.md
@@ -36,6 +36,7 @@
 |`elf`                       |Executable&nbsp;and&nbsp;Linkable&nbsp;Format                                            |<sub></sub>|
 |`ether8023_frame`           |Ethernet&nbsp;802.3&nbsp;frame                                                           |<sub>`inet_packet`</sub>|
 |`exif`                      |Exchangeable&nbsp;Image&nbsp;File&nbsp;Format                                            |<sub></sub>|
+|`fairplay_spc`              |FairPlay&nbsp;Server&nbsp;Playback&nbsp;Context                                          |<sub></sub>|
 |`flac`                      |Free&nbsp;Lossless&nbsp;Audio&nbsp;Codec&nbsp;file                                       |<sub>`flac_metadatablocks` `flac_frame`</sub>|
 |[`flac_frame`](#flac_frame) |FLAC&nbsp;frame                                                                          |<sub></sub>|
 |`flac_metadatablock`        |FLAC&nbsp;metadatablock                                                                  |<sub>`flac_streaminfo` `flac_picture` `vorbis_comment`</sub>|

diff --git a/doc/formats.svg b/doc/formats.svg
diff --git a/format/all/all.go b/format/all/all.go
@@ -15,6 +15,7 @@ import (
 	_ "github.com/wader/fq/format/cbor"
 	_ "github.com/wader/fq/format/dns"
 	_ "github.com/wader/fq/format/elf"
+	_ "github.com/wader/fq/format/fairplay"
 	_ "github.com/wader/fq/format/flac"
 	_ "github.com/wader/fq/format/gif"
 	_ "github.com/wader/fq/format/gzip"

diff --git a/format/all/help.fqtest b/format/all/help.fqtest
@@ -285,6 +285,13 @@ out   # Decode file as exif
 out   $ fq -d exif . file
 out   # Decode value as exif
 out   ... | exif
+"help(fairplay_spc)"
+out fairplay_spc: FairPlay Server Playback Context decoder
+out Examples:
+out   # Decode file as fairplay_spc
+out   $ fq -d fairplay_spc . file
+out   # Decode value as fairplay_spc
+out   ... | fairplay_spc
 "help(flac)"
 out flac: Free Lossless Audio Codec file decoder
 out Examples:

diff --git a/format/fairplay/fairplay.go b/format/fairplay/fairplay.go
@@ -0,0 +1,29 @@
+package fairplay
+
+// https://github.com/easonlin404/ksm/blob/master/ksm.go
+
+import (
+	"github.com/wader/fq/format"
+	"github.com/wader/fq/format/registry"
+	"github.com/wader/fq/pkg/decode"
+)
+
+func init() {
+	registry.MustRegister(decode.Format{
+		Name:        format.FAIRPLAY_SPC,
+		Description: "FairPlay Server Playback Context",
+		DecodeFn:    fairPlaySPCDecode,
+	})
+}
+
+func fairPlaySPCDecode(d *decode.D, in any) any {
+	d.FieldU32("version")
+	d.FieldRawLen("reserved", 32)
+	d.FieldRawLen("iv", 16*8)
+	d.FieldRawLen("aes_key_oaep", 128*8)
+	d.FieldRawLen("certificate_hash", 20*8)
+	payloadLen := d.FieldU32("payload_length")
+	d.FieldRawLen("payload", int64(payloadLen)*8)
+
+	return nil
+}
diff --git a/format/format.go b/format/format.go
@@ -44,6 +44,7 @@ const (
 	ELF                 = "elf"
 	ETHER8023_FRAME     = "ether8023_frame"
 	EXIF                = "exif"
+	FAIRPLAY_SPC        = "fairplay_spc"
 	FLAC                = "flac"
 	FLAC_FRAME          = "flac_frame"
 	FLAC_METADATABLOCK  = "flac_metadatablock"

diff --git a/format/mp4/boxes.go b/format/mp4/boxes.go
@@ -1075,11 +1075,13 @@ func init() {
 				systemIDCommon    = [16]byte{0x10, 0x77, 0xef, 0xec, 0xc0, 0xb2, 0x4d, 0x02, 0xac, 0xe3, 0x3c, 0x1e, 0x52, 0xe2, 0xfb, 0x4b}
 				systemIDWidevine  = [16]byte{0xed, 0xef, 0x8b, 0xa9, 0x79, 0xd6, 0x4a, 0xce, 0xa3, 0xc8, 0x27, 0xdc, 0xd5, 0x1d, 0x21, 0xed}
 				systemIDPlayReady = [16]byte{0x9a, 0x04, 0xf0, 0x79, 0x98, 0x40, 0x42, 0x86, 0xab, 0x92, 0xe6, 0x5b, 0xe0, 0x88, 0x5f, 0x95}
+				systemIDFairPlay  = [16]byte{0x94, 0xce, 0x86, 0xfb, 0x07, 0xff, 0x4f, 0x43, 0xad, 0xb8, 0x93, 0xd2, 0xfa, 0x96, 0x8c, 0xa2}
 			)
 			systemIDNames := scalar.BytesToScalar{
 				{Bytes: systemIDCommon[:], Scalar: scalar.S{Sym: "common"}},
 				{Bytes: systemIDWidevine[:], Scalar: scalar.S{Sym: "widevine"}},
 				{Bytes: systemIDPlayReady[:], Scalar: scalar.S{Sym: "playready"}},
+				{Bytes: systemIDFairPlay[:], Scalar: scalar.S{Sym: "fairplay"}},
 			}
 
 			version := d.FieldU8("version")

diff --git a/pkg/interp/testdata/args.fqtest b/pkg/interp/testdata/args.fqtest
@@ -127,6 +127,7 @@ dns_tcp              DNS packet (TCP)
 elf                  Executable and Linkable Format
 ether8023_frame      Ethernet 802.3 frame
 exif                 Exchangeable Image File Format
+fairplay_spc         FairPlay Server Playback Context
 flac                 Free Lossless Audio Codec file
 flac_frame           FLAC frame
 flac_metadatablock   FLAC metadatablock