Bug 1895599 - Fix omnijar reading with the zip crate. r=gsvelto,supply-chain-reviewers

This crate is only used by the crash reporter and geckodriver, and
geckodriver is only used in testing (if I understand correctly).

In the future we will upstream changes to the zip crate which more
gracefully handles the case which they are trying to cover.

Differential Revision: https://phabricator.services.mozilla.com/D209752

Cargo.lock

@@ -7043,8 +7043,6 @@ dependencies = [
 [[package]]
 name = "zip"
 version = "0.6.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0445d0fbc924bb93539b4316c11afb121ea39296f99a3c4c9edad09e3658cdef"
 dependencies = [
  "byteorder",
  "crc32fast",

Cargo.toml

@@ -188,6 +188,10 @@ web-sys = { path = "build/rust/dummy-web/web-sys" }
 # Overrides to allow easier use of common internal crates.
 moz_asserts = { path = "mozglue/static/rust/moz_asserts" }
 
+
+# Patched version of zip 0.6.4 to allow for reading omnijars.
+zip = { path = "third_party/rust/zip" }
+
 # Patch `rure` to disable building the cdylib and staticlib targets
 # Cargo has no way to disable building targets your dependencies provide which
 # you don't depend on, and linking the cdylib breaks during instrumentation

supply-chain/config.toml

@@ -243,6 +243,10 @@ notes = "Local override of the crates.io crate that uses a non-vendored local co
 [policy.wr_malloc_size_of]
 audit-as-crates-io = false
 
+[policy.zip]
+audit-as-crates-io = true
+notes = "Locally patched version of the zip crate to allow for reading omnijars."
+
 [[exemptions.ahash]]
 version = "0.7.6"
 criteria = "safe-to-deploy"

third_party/rust/zip/src/read.rs

@@ -334,13 +334,10 @@ impl<R: Read + io::Seek> ZipArchive<R> {
                 // offsets all being too small. Get the amount of error by comparing
                 // the actual file position we found the CDE at with the offset
                 // recorded in the CDE.
-                let archive_offset = cde_start_pos
-                    .checked_sub(footer.central_directory_size as u64)
-                    .and_then(|x| x.checked_sub(footer.central_directory_offset as u64))
-                    .ok_or(ZipError::InvalidArchive(
-                        "Invalid central directory size or offset",
-                    ))?;
 
+                // Bug 1895599: omnijars nor other zips we read have data prepended to them; trust
+                // the offsets!
+                let archive_offset = 0;
                 let directory_start = footer.central_directory_offset as u64 + archive_offset;
                 let number_of_files = footer.number_of_files_on_this_disk as usize;
                 Ok((archive_offset, directory_start, number_of_files))

toolkit/crashreporter/client/app/src/lang/omnijar.rs

@@ -31,9 +31,10 @@ pub fn read() -> anyhow::Result<LanguageInfo> {
             .ok_or(anyhow::anyhow!("multilocale file was empty"))?
             .context("failed to read first line of multilocale file")?
     };
+
     let mut file = zip
         .by_name(&format!(
-            "localization/{locale}/toolkit/crashreporter/crashreporter.ftl"
+            "localization/{locale}/crashreporter/crashreporter.ftl"
         ))
         .with_context(|| format!("failed to locate localization file for {locale}"))?;