Support signature verification (minisign)

.github/.cspell/project-dictionary.txt

@@ -14,6 +14,7 @@ mdbook
 microdnf
 nextest
 protoc
+pubkey
 pwsh
 quickinstall
 shellcheck

CHANGELOG.md

@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Support signature verification. ([#237](https://github.com/taiki-e/install-action/pull/237))
+
 - Update `syft@latest` to 0.92.0.
 
 - Update `cargo-make@latest` to 0.37.2.

README.md

@@ -128,6 +128,8 @@ When installing the tool from GitHub Releases, this action will download the too
 
 Additionally, this action will also verify SHA256 checksums for downloaded files in all tools installed from GitHub Releases. This is enabled by default and can be disabled by setting the `checksum` input option to `false`.
 
+Additionally, we also verify signature if the tool distributes signed archives. Signature verification is done at the stage of getting the checksum, so disabling the checksum will also disable signature verification.
+
 See the linked documentation for information on security when installed using [snap](https://snapcraft.io/docs) or [cargo-binstall](https://github.com/cargo-bins/cargo-binstall#faq).
 
 ## Compatibility

tools/codegen/Cargo.toml

@@ -6,9 +6,13 @@ publish = false
 
 [dependencies]
 anyhow = "1"
+flate2 = "1"
 fs-err = "2"
+minisign-verify = "0.2"
 semver = { version = "1", features = ["serde"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 sha2 = "0.10"
+tar = "0.4"
+toml = "0.8"
 ureq = { version = "2", features = ["json"] }

tools/codegen/base/cargo-binstall.json

@@ -4,6 +4,9 @@
   "rust_crate": "${package}",
   "asset_name": "${package}-${rust_target}.tgz",
   "version_range": "latest",
+  "signing": {
+    "kind": "minisign-binstall"
+  },
   "platform": {
     "x86_64_linux_musl": {},
     "x86_64_macos": {

tools/codegen/src/main.rs

@@ -1,9 +1,13 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
+#![allow(clippy::single_match)]
+
 use std::{
     cmp::Reverse,
     collections::{BTreeMap, BTreeSet},
-    env, fmt,
+    env,
+    ffi::OsStr,
+    fmt,
     io::Read,
     path::{Path, PathBuf},
     slice,
@@ -118,19 +122,6 @@ fn main() -> Result<()> {
     }
     let version_req: Option<semver::VersionReq> = match args.get(1) {
         _ if latest_only => {
-            if args.get(1).map(String::as_str) == Some("latest") {
-                if let Some(m) = manifests.map.first_key_value() {
-                    let version = match m.1 {
-                        ManifestRef::Ref { version } => version,
-                        ManifestRef::Real(_) => &m.0 .0,
-                    };
-                    if !manifests.map.is_empty()
-                        && *version >= releases.first_key_value().unwrap().0 .0.clone().into()
-                    {
-                        return Ok(());
-                    }
-                }
-            }
             let req = format!("={}", releases.first_key_value().unwrap().0 .0).parse()?;
             eprintln!("update manifest for versions '{req}'");
             Some(req)
@@ -154,7 +145,7 @@ fn main() -> Result<()> {
                 if manifests.map.is_empty() {
                     format!("={}", releases.first_key_value().unwrap().0 .0).parse()?
                 } else {
-                    format!(">{}", semver_versions.last().unwrap()).parse()?
+                    format!(">={}", semver_versions.last().unwrap()).parse()?
                 }
             } else {
                 version_req.parse()?
@@ -165,6 +156,7 @@ fn main() -> Result<()> {
     };
 
     let mut buf = vec![];
+    let mut buf2 = vec![];
     for (Reverse(semver_version), (version, release)) in &releases {
         if let Some(version_req) = &version_req {
             if !version_req.matches(semver_version) {
@@ -178,6 +170,7 @@ fn main() -> Result<()> {
         }
 
         let mut download_info = BTreeMap::new();
+        let mut pubkey = None;
         for (&platform, base_download_info) in &base_info.platform {
             let asset_names = base_download_info
                 .asset_name
@@ -204,23 +197,101 @@ fn main() -> Result<()> {
                 }
             };
 
-            eprintln!("downloading {url} for checksum...");
-            let download_cache = download_cache_dir.join(format!(
+            eprint!("downloading {url} for checksum ... ");
+            let download_cache = &download_cache_dir.join(format!(
                 "{version}-{platform:?}-{}",
                 Path::new(&url).file_name().unwrap().to_str().unwrap()
             ));
             if download_cache.is_file() {
-                eprintln!(" already downloaded");
+                eprintln!("already downloaded");
                 fs::File::open(download_cache)?.read_to_end(&mut buf)?;
             } else {
                 download(&url)?.into_reader().read_to_end(&mut buf)?;
-                eprintln!(" download complete");
+                eprintln!("download complete");
                 fs::write(download_cache, &buf)?;
             }
             eprintln!("getting sha256 hash for {url}");
             let hash = Sha256::digest(&buf);
             let hash = format!("{hash:x}");
             eprintln!("{hash} *{asset_name}");
+            let bin_url = &url;
+
+            match base_info.signing {
+                Some(Signing { kind: SigningKind::MinisignBinstall }) => {
+                    let url = url.clone() + ".sig";
+                    let sig_download_cache = &download_cache.with_extension(format!(
+                        "{}.sig",
+                        download_cache.extension().unwrap_or_default().to_str().unwrap()
+                    ));
+                    eprint!("downloading {url} for signature validation ... ");
+                    let sig = if sig_download_cache.is_file() {
+                        eprintln!("already downloaded");
+                        minisign_verify::Signature::from_file(sig_download_cache)?
+                    } else {
+                        let buf = download(&url)?.into_string()?;
+                        eprintln!("download complete");
+                        fs::write(sig_download_cache, &buf)?;
+                        minisign_verify::Signature::decode(&buf)?
+                    };
+
+                    let Some(crates_io_info) = &crates_io_info else {
+                        bail!("signing kind minisign-binstall is supported only for rust crate");
+                    };
+                    let v =
+                        crates_io_info.versions.iter().find(|v| v.num == *semver_version).unwrap();
+                    let url = format!("https://crates.io{}", v.dl_path);
+                    let crate_download_cache =
+                        &download_cache_dir.join(format!("{version}-Cargo.toml"));
+                    eprint!("downloading {url} for signature verification ... ");
+                    if crate_download_cache.is_file() {
+                        eprintln!("already downloaded");
+                    } else {
+                        download(&url)?.into_reader().read_to_end(&mut buf2)?;
+                        let hash = Sha256::digest(&buf2);
+                        if format!("{hash:x}") != v.checksum {
+                            bail!("checksum mismatch for {url}");
+                        }
+                        let decoder = flate2::read::GzDecoder::new(&*buf2);
+                        let mut archive = tar::Archive::new(decoder);
+                        for entry in archive.entries()? {
+                            let mut entry = entry?;
+                            let path = entry.path()?;
+                            if path.file_name() == Some(OsStr::new("Cargo.toml")) {
+                                entry.unpack(crate_download_cache)?;
+                                break;
+                            }
+                        }
+                        buf2.clear();
+                        eprintln!("download complete");
+                    }
+                    if pubkey.is_none() {
+                        let cargo_manifest = toml::from_str::<cargo_manifest::Manifest>(
+                            &fs::read_to_string(crate_download_cache)?,
+                        )?;
+                        eprintln!(
+                            "algorithm: {}",
+                            cargo_manifest.package.metadata.binstall.signing.algorithm
+                        );
+                        eprintln!(
+                            "pubkey: {}",
+                            cargo_manifest.package.metadata.binstall.signing.pubkey
+                        );
+                        assert_eq!(
+                            cargo_manifest.package.metadata.binstall.signing.algorithm,
+                            "minisign"
+                        );
+                        pubkey = Some(minisign_verify::PublicKey::from_base64(
+                            &cargo_manifest.package.metadata.binstall.signing.pubkey,
+                        )?);
+                    }
+                    let pubkey = pubkey.as_ref().unwrap();
+                    eprint!("verifying signature for {bin_url} ... ");
+                    let allow_legacy = false;
+                    pubkey.verify(&buf, &sig, allow_legacy)?;
+                    eprintln!("done");
+                }
+                None => {}
+            }
 
             download_info.insert(platform, ManifestDownloadInfo {
                 url: Some(url),
@@ -620,10 +691,27 @@ struct BaseManifest {
     asset_name: Option<StringOrArray>,
     /// Path to binary in archive. Default to `${tool}${exe}`.
     bin: Option<String>,
+    signing: Option<Signing>,
     platform: BTreeMap<HostPlatform, BaseManifestPlatformInfo>,
     version_range: Option<String>,
 }
 
+#[derive(Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
+struct Signing {
+    kind: SigningKind,
+}
+
+#[derive(Debug, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "kebab-case")]
+#[serde(deny_unknown_fields)]
+enum SigningKind {
+    /// algorithm: minisign
+    /// public key: package.metadata.binstall.signing.pubkey at Cargo.toml
+    /// <https://github.com/cargo-bins/cargo-binstall/blob/HEAD/SIGNING.md>
+    MinisignBinstall,
+}
+
 #[derive(Debug, Deserialize)]
 #[serde(deny_unknown_fields)]
 struct BaseManifestPlatformInfo {
@@ -743,7 +831,39 @@ mod crates_io {
 
     #[derive(Debug, Deserialize)]
     pub struct Version {
+        pub checksum: String,
+        pub dl_path: String,
         pub num: semver::Version,
         pub yanked: bool,
     }
 }
+
+mod cargo_manifest {
+    use serde::Deserialize;
+
+    #[derive(Debug, Deserialize)]
+    pub struct Manifest {
+        pub package: Package,
+    }
+
+    #[derive(Debug, Deserialize)]
+    pub struct Package {
+        pub metadata: Metadata,
+    }
+
+    #[derive(Debug, Deserialize)]
+    pub struct Metadata {
+        pub binstall: Binstall,
+    }
+
+    #[derive(Debug, Deserialize)]
+    pub struct Binstall {
+        pub signing: BinstallSigning,
+    }
+
+    #[derive(Debug, Deserialize)]
+    pub struct BinstallSigning {
+        pub algorithm: String,
+        pub pubkey: String,
+    }
+}