Create & verify PAYLOADDIGEST, PAYLOADDIGESTALT

CHANGELOG.md

@@ -25,6 +25,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   `get_entry_data_as_u16_array()`, `get_entry_data_as_u32()`, `get_entry_data_as_u32_array()`,
   `get_entry_data_as_u64()`, `get_entry_data_as_u64_array()`, `get_entry_data_as_string_array()`,
   `get_entry_data_as_i18n_string()`
+- Added `verify_signature()` and `verify_digests()` to `RPMPackage` to enable checking the integrity
+  and provenance of packages.
 
 ### Fixed
 
@@ -33,6 +35,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   did not have any files associated.
 - Ensured that digests are always added to built RPMs. Previously they would not be included unless
   the "signature-meta" (or "signature-pgp") features were enabled.
+- Added `PAYLOADDIGEST`, `PAYLOADDIGESTALT`, and `PAYLOADDIGESTALGO` tags to built packages.
 
 ### Breaking Changes
 

Cargo.toml

@@ -42,10 +42,10 @@ enum-display-derive = "0.1"
 cpio = "0.2"
 # consider migrating to flate2
 libflate = "1"
+digest = "0.10"
 sha2 = "0.10"
 md-5 = "0.10"
 sha1 = "0.10"
-rand = { version = "0.8" }
 pgp = { version = "0.9", optional = true }
 chrono = "0.4"
 log = "0.4"
@@ -60,8 +60,6 @@ async-std = { version = "1.12.0", optional = true }
 tokio = { version = "1", optional = true }
 tokio-util = { version = "0.7.4", features = ["compat"], optional = true }
 
-digest = "0.10.6"
-
 [dev-dependencies]
 rsa = { version = "0.8" }
 rsa-der = { version = "^0.3.0" }

src/constants.rs

@@ -335,12 +335,12 @@ pub enum IndexTag {
     RPMTAG_TRANSFILETRIGGERTYPE = 5089,
     RPMTAG_FILESIGNATURES = 5090,
     RPMTAG_FILESIGNATURELENGTH = 5091,
-    RPMTAG_PAYLOADDIGEST = 5092,
+    RPMTAG_PAYLOADDIGEST = 5092, // hex-encoded string representing the digest of the payload
     RPMTAG_PAYLOADDIGESTALGO = 5093,
     RPMTAG_AUTOINSTALLED = 5094,
     RPMTAG_IDENTITY = 5095,
     RPMTAG_MODULARITYLABEL = 5096,
-    RPMTAG_PAYLOADDIGESTALT = 5097,
+    RPMTAG_PAYLOADDIGESTALT = 5097, // hex-encoded string representing the digest of the payload without compression
     RPMTAG_ARCHSUFFIX = 5098,
     RPMTAG_SPEC = 5099,
     RPMTAG_TRANSLATIONURL = 5100,
@@ -375,11 +375,12 @@ pub enum IndexSignatureTag {
     /// This tag specifies the uncompressed size of the Payload archive, including the cpio headers.
     RPMSIGTAG_PAYLOADSIZE = HEADER_TAGBASE + 7,
 
-    /// This  index  contains  the  SHA1  checksum  of  the  entire  Header  Section,
-    /// including the Header Record, Index Records and Header store.
+    /// The SHA1 checksum of the entire Header Section, including the Header Record, Index Records and
+    /// Header store, stored as a hex-encoded string.
     RPMSIGTAG_SHA1 = 269,
 
-    /// This tag specifies the 128-bit MD5 checksum of the combined Header and Archive sections.
+    /// This tag specifies the 128-bit MD5 checksum of the combined Header and Archive sections, stored as
+    /// a binary representation.
     RPMSIGTAG_MD5 = 1004,
 
     /// The tag contains the DSA signature of the Header section.
@@ -415,8 +416,8 @@ pub enum IndexSignatureTag {
     /// The data is formatted as a Version 3 Signature Packet as specified in RFC 2440: OpenPGP Message Format.
     RPMSIGTAG_GPG = 1005,
 
-    /// This index contains the SHA256 checksum of the entire Header Section,
-    /// including the Header Record, Index Records and Header store.
+    /// This index contains the SHA256 checksum of the entire Header Section, including the Header Record,
+    /// Index Records and Header store, stored as a hex-encoded string.
     RPMSIGTAG_SHA256 = IndexTag::RPMTAG_SHA256HEADER as u32,
 
     /// A silly tag for a date.

src/errors.rs

@@ -73,6 +73,9 @@ pub enum RPMError {
         key_ref: String,
     },
 
+    #[error("digests from content did not match those in the header")]
+    DigestMismatchError,
+
     #[error("unable to find key with key-ref: {key_ref}")]
     KeyNotFoundError { key_ref: String },
 

src/rpm/builder.rs

@@ -8,6 +8,7 @@ use std::os::unix::fs::PermissionsExt;
 use std::path::{Path, PathBuf};
 use std::time::{SystemTime, UNIX_EPOCH};
 
+use digest::Digest;
 use gethostname::gethostname;
 
 use super::compressor::Compressor;
@@ -328,8 +329,6 @@ impl RPMBuilder {
         modified_at: u32,
         options: RPMFileOptions,
     ) -> Result<(), RPMError> {
-        use sha2::Digest;
-
         let dest = options.destination;
         if !dest.starts_with("./") && !dest.starts_with('/') {
             return Err(RPMError::InvalidDestinationPath {
@@ -501,7 +500,7 @@ impl RPMBuilder {
             let Digests {
                 header_and_content_digest: header_and_content_digest_md5,
                 header_digest: header_digest_sha1,
-            } = RPMPackage::create_digests_from_readers(
+            } = RPMPackage::create_legacy_header_digests(
                 &mut header.as_slice(),
                 header_and_content_cursor,
             )?;
@@ -546,7 +545,7 @@ impl RPMBuilder {
         let Digests {
             header_and_content_digest: header_and_content_digest_md5,
             header_digest: header_digest_sha1,
-        } = RPMPackage::create_digests_from_readers(
+        } = RPMPackage::create_legacy_header_digests(
             &mut header.as_slice(),
             header_and_content_cursor,
         )?;
@@ -592,6 +591,13 @@ impl RPMBuilder {
         // Lead is not important. just build it here
 
         let lead = Lead::new(&self.name);
+        let possible_compression_details = self.compressor.get_details();
+
+        // Make the borrow checker happy
+        let is_zstd = matches!(self.compressor, Compressor::Zstd(_));
+        // Calculate the sha256 of the archive as we write it into the compressor, so that we don't
+        // need to keep two copies in memory simultaneously.
+        let mut archive = Sha256Writer::new(&mut self.compressor);
 
         let mut ino_index = 1;
 
@@ -645,13 +651,14 @@ impl RPMBuilder {
                 .ino(ino_index)
                 .uid(self.uid.unwrap_or(0))
                 .gid(self.gid.unwrap_or(0))
-                .write(&mut self.compressor, content.len() as u32);
+                .write(&mut archive, content.len() as u32);
 
             writer.write_all(&content)?;
             writer.finish()?;
 
             ino_index += 1;
         }
+        cpio::newc::trailer(&mut archive)?;
 
         self.provides
             .push(Dependency::eq(self.name.clone(), self.version.clone()));
@@ -675,7 +682,7 @@ impl RPMBuilder {
             "4.0-1".to_string(),
         ));
 
-        if matches!(self.compressor, Compressor::Zstd(_)) {
+        if is_zstd {
             self.requires.push(Dependency::rpmlib(
                 "rpmlib(PayloadIsZstd)".to_string(),
                 "5.4.18-1".to_string(),
@@ -960,7 +967,34 @@ impl RPMBuilder {
             ),
         ]);
 
-        let possible_compression_details = self.compressor.get_details();
+        // digest of the uncompressed raw archive calculated on the inner writer
+        let raw_archive_digest_sha256 = hex::encode(archive.into_digest());
+        let payload = self.compressor.finish_compression()?;
+
+        // digest of the post-compression archive (payload)
+        let payload_digest_sha256 = {
+            let mut hasher = sha2::Sha256::default();
+            hasher.update(payload.as_slice());
+            hex::encode(hasher.finalize())
+        };
+
+        actual_records.extend([
+            IndexEntry::new(
+                IndexTag::RPMTAG_PAYLOADDIGEST,
+                offset,
+                IndexData::StringArray(vec![payload_digest_sha256]),
+            ),
+            IndexEntry::new(
+                IndexTag::RPMTAG_PAYLOADDIGESTALGO,
+                offset,
+                IndexData::Int32(vec![FileDigestAlgorithm::Sha2_256 as u32]),
+            ),
+            IndexEntry::new(
+                IndexTag::RPMTAG_PAYLOADDIGESTALT,
+                offset,
+                IndexData::StringArray(vec![raw_archive_digest_sha256]),
+            ),
+        ]);
 
         if let Some(details) = possible_compression_details {
             actual_records.push(IndexEntry::new(
@@ -1184,9 +1218,7 @@ impl RPMBuilder {
         }
 
         let header = Header::from_entries(actual_records, IndexTag::RPMTAG_HEADERIMMUTABLE);
-        self.compressor = cpio::newc::trailer(self.compressor)?;
-        let content = self.compressor.finish_compression()?;
 
-        Ok((lead, header, content))
+        Ok((lead, header, payload))
     }
 }

src/rpm/headers/header.rs

@@ -416,15 +416,15 @@ impl Default for FileCategory {
 pub enum FileDigestAlgorithm {
     // broken and very broken
     Md5 = constants::PGPHASHALGO_MD5,
-    Sha1 = constants::PGPHASHALGO_SHA1,
-    Md2 = constants::PGPHASHALGO_MD2,
+    // Sha1 = constants::PGPHASHALGO_SHA1,
+    // Md2 = constants::PGPHASHALGO_MD2,
 
-    // not proven to be broken, weaker variants broken
-    #[allow(non_camel_case_types)]
-    Haval_5_160 = constants::PGPHASHALGO_HAVAL_5_160, // not part of PGP
-    Ripemd160 = constants::PGPHASHALGO_RIPEMD160,
+    // // not proven to be broken, weaker variants broken
+    // #[allow(non_camel_case_types)]
+    // Haval_5_160 = constants::PGPHASHALGO_HAVAL_5_160, // not part of PGP
+    // Ripemd160 = constants::PGPHASHALGO_RIPEMD160,
 
-    Tiger192 = constants::PGPHASHALGO_TIGER192, // not part of PGP
+    // Tiger192 = constants::PGPHASHALGO_TIGER192, // not part of PGP
     Sha2_256 = constants::PGPHASHALGO_SHA256,
     Sha2_384 = constants::PGPHASHALGO_SHA384,
     Sha2_512 = constants::PGPHASHALGO_SHA512,

src/rpm/headers/types.rs

@@ -1,5 +1,6 @@
 //! A collection of types used in various header records.
 use crate::{constants::*, errors};
+use digest::Digest;
 
 /// Describes a file present in the rpm file.
 pub struct RPMFileEntry {
@@ -315,6 +316,36 @@ impl Dependency {
     }
 }
 
+/// A wrapper for calculating the sha256 checksum of the contents written to it
+pub struct Sha256Writer<W> {
+    writer: W,
+    hasher: sha2::Sha256,
+}
+
+impl<W> Sha256Writer<W> {
+    pub fn new(writer: W) -> Self {
+        Sha256Writer {
+            writer,
+            hasher: sha2::Sha256::new(),
+        }
+    }
+
+    pub fn into_digest(self) -> impl AsRef<[u8]> {
+        self.hasher.finalize()
+    }
+}
+
+impl<W: std::io::Write> std::io::Write for Sha256Writer<W> {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        self.hasher.update(buf);
+        self.writer.write(buf)
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        self.writer.flush()
+    }
+}
+
 mod test {
 
     #[test]