Imports: resolve a leading ./ in an apt index entry's Filename, as apt does

crates/formats/apt/src/import.rs

@@ -283,7 +283,8 @@ pub struct Entry {
     pub package: String,
     pub version: String,
     pub architecture: String,
-    /// Where the package is, below the repository's base URL.
+    /// Where the package is, below the repository's base URL, its `.`
+    /// segments dropped ([`resolve_filename`]).
     pub filename: String,
     pub size: Option<u64>,
     /// Lowercase hex digests.
@@ -339,6 +340,18 @@ impl Entry {
     }
 }
 
+/// A `Filename` as apt resolves it against the base URL: its `.` segments
+/// (the leading `./` of `dpkg-scanpackages ./pool`) dropped. Everything else
+/// stays, a `..`, an empty segment or a leading `/` among it, for
+/// [`Entry::problem`] to refuse.
+pub fn resolve_filename(filename: &str) -> String {
+    filename
+        .split('/')
+        .filter(|segment| *segment != ".")
+        .collect::<Vec<_>>()
+        .join("/")
+}
+
 /// A lowercase hex digest of `len` digits, if `value` is one.
 fn hex_digest(value: &str, len: usize) -> Option<String> {
     (value.len() == len && value.bytes().all(|b| b.is_ascii_hexdigit()))
@@ -422,7 +435,7 @@ pub fn read_packages(index: impl Read) -> Result<Vec<Entry>, String> {
             }
             "version" => entry.version = value.to_string(),
             "architecture" => entry.architecture = value.to_string(),
-            "filename" => entry.filename = value.to_string(),
+            "filename" => entry.filename = resolve_filename(value),
             "size" => entry.size = value.parse().ok(),
             "sha256" => entry.sha256 = hex_digest(value, 64),
             "sha512" => entry.sha512 = hex_digest(value, 128),
@@ -685,6 +698,43 @@ mod tests {
         assert!(component_problem("updates/main").is_some());
     }
 
+    #[test]
+    fn a_filename_is_resolved_as_apt_resolves_it() {
+        // `dpkg-scanpackages ./pool` and `apt-ftparchive packages ./pool`
+        // write a leading `./`.
+        let index = b"Package: hello\nVersion: 1.0\nArchitecture: amd64\n\
+            Filename: ./pool/main/h/hello/./hello_1.0_amd64.deb\nSize: 42\n\
+            SHA256: 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\n";
+        let entries = read_packages(&index[..]).unwrap();
+        assert_eq!(entries[0].filename, "pool/main/h/hello/hello_1.0_amd64.deb");
+        assert_eq!(entries[0].problem(), None);
+        for (listed, resolved) in [
+            ("pool/x.deb", "pool/x.deb"),
+            ("./pool/x.deb", "pool/x.deb"),
+            ("././pool/./x.deb", "pool/x.deb"),
+            // A `..`, an empty segment and a leading `/` stay, refused.
+            ("./../x.deb", "../x.deb"),
+            ("pool/../../x.deb", "pool/../../x.deb"),
+            ("pool//x.deb", "pool//x.deb"),
+            ("/./pool/x.deb", "/pool/x.deb"),
+        ] {
+            assert_eq!(resolve_filename(listed), resolved, "{listed}");
+        }
+        for refused in ["./../x.deb", "pool/./../x.deb", "/./pool/x.deb", "./"] {
+            let entry = read_packages(
+                format!(
+                    "Package: a\nVersion: 1\nArchitecture: all\nFilename: {refused}\n\
+                     Size: 1\nSHA256: {}\n",
+                    "0".repeat(64)
+                )
+                .as_bytes(),
+            )
+            .unwrap()
+            .remove(0);
+            assert!(entry.problem().is_some(), "{refused}");
+        }
+    }
+
     #[test]
     fn a_malformed_index_is_refused() {
         for bad in [

crates/server/tests/apt_import.rs

@@ -13,7 +13,8 @@
 //!   it in, whatever its `Section` says; a `Packages` entry whose size or
 //!   SHA-256 does not match its `.deb` fails that item, as do one the
 //!   source does not have and one whose `Filename` is outside the
-//!   repository, and the import completes; an index that does not match
+//!   repository, and the import completes; a `Filename` that starts with
+//!   `./` (`dpkg-scanpackages ./pool`) is resolved below the repository; an index that does not match
 //!   `Release` fails the scan; a version Forge holds with other bytes
 //!   follows `on_conflict`, decided without a download; a dry run writes
 //!   nothing;
@@ -554,15 +555,13 @@ async fn apt_import_from_a_static_repository_checks_every_package_and_index() {
             ),
         ],
     );
+    // `fine`'s Filename starts with `./`, as `dpkg-scanpackages ./pool`
+    // writes it: apt resolves it below the repository.
+    let dotted = format!("./{}", pool["fine"]);
     mirror.index(
         "main",
         "arm64",
-        &[stanza(
-            &fine_control,
-            pool["fine"],
-            fine.len(),
-            &sha256(&fine),
-        )],
+        &[stanza(&fine_control, &dotted, fine.len(), &sha256(&fine))],
     );
     mirror.release(Some(&key));
 
@@ -601,6 +600,8 @@ async fn apt_import_from_a_static_repository_checks_every_package_and_index() {
         "{found:?}"
     );
     assert_eq!(item(&found, "fine:arm64")["version"], "1:2.0-1");
+    assert_eq!(item(&found, "fine:arm64")["state"], "imported", "{found:?}");
+    assert_eq!(mirror.gets(pool["fine"]), 1);
 
     // `moved` stays in main, where the source lists it.
     assert_eq!(listed(&srv, &dst, "main", "amd64").await, ["moved"]);

docs/changes/2.2.0/754.fixed.md

@@ -0,0 +1,5 @@
+An import of an apt repository made with `dpkg-scanpackages ./pool` or
+`apt-ftparchive packages ./pool` failed every package with "is no path below
+the repository", because their index entries' `Filename` starts with `./`.
+The import now drops a `Filename`'s `.` segments before it checks and
+downloads the package, as apt does; a `..` is still refused.