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src/router/custom_3dmv/package.rs

@@ -0,0 +1,88 @@
+use std::collections::HashMap;
+use std::fs;
+use std::io::{Cursor, Read, Seek, Write};
+use zip::write::SimpleFileOptions;
+
+use super::{blob_path, field_key};
+use crate::database::custom_3dmv as database;
+
+// Export packages carry the stored blobs byte-for-byte (they ARE the original
+// uploads - nothing is transcoded) plus the upload metadata, so an MV can be
+// re-uploaded on any ew server. Layout of the zip:
+//   manifest.json   {format, name, name_en, music_id, member_count}
+//   model_{slot} / motion_{slot} / facial_{slot} / camera / config / stage
+// published is a per-server setting and deliberately not part of the package.
+
+pub fn build(mv_id: i64) -> Result<Vec<u8>, String> {
+    let mv = database::get_mv(mv_id).ok_or(String::from("MV not found"))?;
+
+    let manifest = jzon::object!{
+        "format": 1,
+        "name": mv["name"].clone(),
+        "name_en": mv["name_en"].clone(),
+        "music_id": mv["music_id"].clone(),
+        "member_count": mv["member_count"].clone()
+    };
+
+    let mut zip = zip::ZipWriter::new(Cursor::new(Vec::new()));
+    let options = SimpleFileOptions::default();
+    let mut add = |name: &str, bytes: &[u8]| -> Result<(), String> {
+        zip.start_file(name, options).map_err(|e| e.to_string())?;
+        zip.write_all(bytes).map_err(|e| e.to_string())
+    };
+
+    add("manifest.json", jzon::stringify(manifest).as_bytes())?;
+    for file in mv["files"].members() {
+        let Some(name) = field_key(file) else { continue; };
+        let md5 = file["md5"].as_str().unwrap_or("");
+        let bytes = fs::read(blob_path(md5)).map_err(|e| e.to_string())?;
+        add(&name, &bytes)?;
+    }
+
+    Ok(zip.finish().map_err(|e| e.to_string())?.into_inner())
+}
+
+fn read_entry<R: Read + Seek>(archive: &mut zip::ZipArchive<R>, name: &str) -> Option<Vec<u8>> {
+    let mut file = archive.by_name(name).ok()?;
+    let mut bytes = Vec::new();
+    file.read_to_end(&mut bytes).ok()?;
+    Some(bytes)
+}
+
+// Expands a package into the same field map the upload form produces. The
+// package's metadata wins over form fields - except music_id, which is a
+// server-local id: a form-supplied song wins, and the manifest's only fills
+// in when the form left it blank (same-server re-upload)
+pub fn expand(package: &[u8], fields: &mut HashMap<String, Vec<u8>>) -> Result<(), String> {
+    let mut archive = zip::ZipArchive::new(Cursor::new(package)).map_err(|_| String::from("Package is not a valid zip file"))?;
+
+    let manifest = read_entry(&mut archive, "manifest.json").ok_or(String::from("Package has no manifest.json"))?;
+    let manifest = jzon::parse(&String::from_utf8_lossy(&manifest)).map_err(|_| String::from("Package manifest is not valid JSON"))?;
+    if manifest["format"].as_i64() != Some(1) {
+        return Err(String::from("Unsupported package format"));
+    }
+
+    for key in ["name", "name_en", "member_count"] {
+        if !manifest[key].is_null() {
+            fields.insert(key.to_string(), manifest[key].to_string().into_bytes());
+        }
+    }
+    if !fields.get("music_id").is_some_and(|v| !v.is_empty()) && !manifest["music_id"].is_null() {
+        fields.insert(String::from("music_id"), manifest["music_id"].to_string().into_bytes());
+    }
+
+    let member_count = manifest["member_count"].as_i64().unwrap_or(0);
+    for slot in 1..=member_count.clamp(0, super::MAX_MEMBER_COUNT) {
+        for role in ["model", "motion", "facial"] {
+            if let Some(bytes) = read_entry(&mut archive, &format!("{}_{}", role, slot)) {
+                fields.insert(format!("{}_{}", role, slot), bytes);
+            }
+        }
+    }
+    for name in ["camera", "config", "stage"] {
+        if let Some(bytes) = read_entry(&mut archive, name) {
+            fields.insert(String::from(name), bytes);
+        }
+    }
+    Ok(())
+}

src/router/custom_3dmv/vmd.rs

@@ -0,0 +1,121 @@
+// Structural validation of a VMD (Vocaloid Motion Data) upload: the header
+// magic plus a full section walk with bounds checks, so a truncated or
+// corrupt file is rejected cheaply at upload time instead of crashing a
+// client mid-live. Nothing here decodes the animation - the stored bytes are
+// served verbatim and the client owns the semantics.
+//
+// Layout (little-endian): 30-byte magic "Vocaloid Motion Data 0002"
+// (NUL-padded), 20-byte model name, then up to 6 sections, each a uint32
+// count followed by fixed-size records - bone (111), morph (23), camera (61),
+// light (28), self-shadow (9) - and the property/IK section whose records are
+// variable-sized (9 bytes + 21 per IK entry). Camera-only and motion-only
+// files legitimately end early: EOF on a section boundary reads as count 0.
+
+const MAGIC_V2: &[u8] = b"Vocaloid Motion Data 0002";
+const MAGIC_V1: &[u8] = b"Vocaloid Motion Data file";
+const HEADER_LEN: usize = 30 + 20;
+
+// (record size, section name) for the fixed-size sections, in file order
+const FIXED_SECTIONS: &[(usize, &str)] = &[
+    (111, "bone"),
+    (23, "morph"),
+    (61, "camera"),
+    (28, "light"),
+    (9, "self-shadow")
+];
+
+fn read_count(bytes: &[u8], offset: usize) -> Option<u32> {
+    let end = offset.checked_add(4)?;
+    Some(u32::from_le_bytes(bytes.get(offset..end)?.try_into().unwrap()))
+}
+
+pub fn validate(label: &str, bytes: &[u8]) -> Result<(), String> {
+    if bytes.len() < HEADER_LEN {
+        return Err(format!("'{}' is too short to be a VMD file", label));
+    }
+    if bytes.starts_with(MAGIC_V1) {
+        return Err(format!("'{}' is a version 1 VMD (\"Vocaloid Motion Data file\") - re-save it as version 2 in MMD", label));
+    }
+    if !bytes.starts_with(MAGIC_V2) {
+        return Err(format!("'{}' is not a VMD file (missing the \"Vocaloid Motion Data 0002\" header)", label));
+    }
+
+    let mut offset = HEADER_LEN;
+    for (record_size, section) in FIXED_SECTIONS {
+        // EOF exactly on a section boundary: the remaining sections are absent
+        if offset == bytes.len() {
+            return Ok(());
+        }
+        let Some(count) = read_count(bytes, offset) else {
+            return Err(format!("'{}' is truncated in the {} section header", label, section));
+        };
+        offset += 4;
+        let section_len = (count as usize).checked_mul(*record_size)
+            .filter(|len| offset.checked_add(*len).is_some_and(|end| end <= bytes.len()))
+            .ok_or(format!("'{}' is truncated: the {} section claims {} records past the end of the file", label, section, count))?;
+        offset += section_len;
+    }
+
+    // Property/IK section: uint32 frame, byte visible, uint32 ikCount, then
+    // ikCount x (20-byte bone name + 1-byte enabled)
+    if offset == bytes.len() {
+        return Ok(());
+    }
+    let Some(count) = read_count(bytes, offset) else {
+        return Err(format!("'{}' is truncated in the property section header", label));
+    };
+    offset += 4;
+    for _ in 0..count {
+        let Some(ik_count) = read_count(bytes, offset + 5) else {
+            return Err(format!("'{}' is truncated in the property section", label));
+        };
+        let record_len = (ik_count as usize).checked_mul(21)
+            .and_then(|len| len.checked_add(9))
+            .filter(|len| offset.checked_add(*len).is_some_and(|end| end <= bytes.len()))
+            .ok_or(format!("'{}' is truncated in the property section", label))?;
+        offset += record_len;
+    }
+    // Trailing bytes after the last section are tolerated, like MMD does
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn structure_walk_accepts_real_shapes_and_rejects_corruption() {
+        let vmd = crate::router::custom_3dmv::tests::test_vmd(1);
+        assert!(validate("motion_1", &vmd).is_ok());
+
+        // Camera-only file: sections end after camera
+        let cam = crate::router::custom_3dmv::tests::test_camera_vmd(2);
+        assert!(validate("camera", &cam).is_ok());
+
+        // A bare header with every section absent is structurally fine
+        let mut bare = Vec::new();
+        bare.extend(MAGIC_V2);
+        bare.resize(HEADER_LEN, 0);
+        assert!(validate("motion_1", &bare).is_ok());
+
+        // Truncations and lies
+        assert!(validate("motion_1", &vmd[..vmd.len() - 1]).unwrap_err().contains("truncated"));
+        assert!(validate("motion_1", &vmd[..HEADER_LEN + 2]).unwrap_err().contains("truncated"));
+        let mut liar = vmd.clone();
+        liar[HEADER_LEN] = 200; // bone count far past EOF
+        assert!(validate("motion_1", &liar).unwrap_err().contains("claims 200 records"));
+        // A count that would overflow the length math
+        let mut overflow = bare.clone();
+        overflow.extend(u32::MAX.to_le_bytes());
+        assert!(validate("motion_1", &overflow).unwrap_err().contains("truncated"));
+
+        // Wrong or old magic
+        assert!(validate("motion_1", b"garbage").unwrap_err().contains("too short"));
+        let mut wrong = vmd.clone();
+        wrong[0] = b'X';
+        assert!(validate("motion_1", &wrong).unwrap_err().contains("not a VMD"));
+        let mut v1 = vmd.clone();
+        v1[..MAGIC_V1.len()].copy_from_slice(MAGIC_V1);
+        assert!(validate("motion_1", &v1).unwrap_err().contains("version 1"));
+    }
+}

src/router/custom_song.rs

@@ -152,6 +152,18 @@ pub fn hidden_live_ids_for_user(uid: i64) -> JsonValue {
     database::non_public_music_ids_for(uid)
 }
 
+// Whether `uid` may attach cross-feature content (a custom 3D MV) to this
+// song: it must exist, and be theirs or publicly visible. Mirrors
+// custom_card::validate_character_ref
+pub fn can_reference_song(uid: i64, music_id: i64) -> Result<(), String> {
+    if !disabled()
+        && database::get_song_owner(music_id).is_some()
+        && (database::get_song_owner(music_id) == Some(uid) || database::song_publicly_visible(music_id)) {
+        return Ok(());
+    }
+    Err(format!("Unknown music_id '{}'", music_id))
+}
+
 fn song_path(music_id: i64, file: &str) -> String {
     get_data_path(&format!("custom_songs/{}/{}", music_id, file))
 }
@@ -1135,6 +1147,8 @@ async fn delete(req: HttpRequest, body: String) -> HttpResponse {
     // Global clear-rate stats for the dead live id (per-user score records are
     // wiped lazily on each user's next userdata pull)
     crate::router::clear_rate::purge_live(music_id);
+    // A custom 3D MV can't outlive the song it plays over
+    crate::router::custom_3dmv::purge_song(music_id);
 
     let _ = fs::remove_dir_all(get_data_path(&format!("custom_songs/{}", music_id)));
     // Audio is content-addressed and may be shared with another upload

src/router/webui.rs

@@ -229,6 +229,7 @@ pub fn server_info(_req: HttpRequest) -> HttpResponse {
             account_import: get_config()["import"].as_bool().unwrap(),
             custom_songs: !crate::router::custom_song::disabled(),
             custom_cards: !crate::router::custom_card::disabled(),
+            custom_3dmv: !crate::router::custom_3dmv::disabled(),
             links: {
                 global: args.global_android,
                 japan: args.japan_android,
@@ -451,6 +452,22 @@ pub fn custom_card_limits(req: HttpRequest) -> HttpResponse {
         .body(jzon::stringify(resp))
 }
 
+pub fn custom_3dmv_limits(req: HttpRequest) -> HttpResponse {
+    if crate::router::custom_3dmv::disabled() {
+        return HttpResponse::NotFound().finish();
+    }
+    if session_uid(&req).is_none() {
+        return error("Not logged in");
+    }
+    let resp = object!{
+        result: "OK",
+        data: crate::router::custom_3dmv::upload_limits()
+    };
+    HttpResponse::Ok()
+        .insert_header(ContentType::json())
+        .body(jzon::stringify(resp))
+}
+
 pub fn my_scopes(req: HttpRequest) -> HttpResponse {
     let Some(uid) = session_uid(&req) else {
         return error("Not logged in");
@@ -463,6 +480,7 @@ pub fn my_scopes(req: HttpRequest) -> HttpResponse {
             can_upload_cards: permissions::has(uid, permissions::CARD_UPLOAD),
             can_publish_cards: permissions::has(uid, permissions::CARD_PUBLISH),
             can_edit_any_cards: permissions::has(uid, permissions::CARD_EDIT),
+            can_edit_any_3dmv: permissions::has(uid, permissions::MV_EDIT),
             can_manage_permissions: permissions::has(uid, permissions::PERMISSION_GRANT)
                 || permissions::has(uid, permissions::PERMISSION_REVOKE),
             can_manage_announcements: permissions::has(uid, permissions::ANNOUNCEMENT_MANAGE)