From bf867c50126602f4d53ecf96ed641b8f32fbdafd Mon Sep 17 00:00:00 2001
From: Chris Hennick <hennickc@amazon.com>
Date: Thu, 11 May 2023 19:25:32 -0700
Subject: [PATCH] Bug fix: skip invalid filenames during write fuzz

---
 Cargo.toml                      |  1 +
 fuzz/fuzz_targets/fuzz_write.rs |  3 +++
 src/write.rs                    | 39 ++++++++++++++++++---------------
 3 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index f8068edf..71717485 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,6 +24,7 @@ pbkdf2 = {version = "0.12.1", optional = true }
 sha1 = {version = "0.10.5", optional = true }
 time = { version = "0.3.21", optional = true, default-features = false, features = ["std"] }
 zstd = { version = "0.12.3", optional = true }
+visibility = "0.0.1"
 
 [target.'cfg(any(all(target_arch = "arm", target_pointer_width = "32"), target_arch = "mips", target_arch = "powerpc"))'.dependencies]
 crossbeam-utils = "0.8.15"
diff --git a/fuzz/fuzz_targets/fuzz_write.rs b/fuzz/fuzz_targets/fuzz_write.rs
index ff495ffa..aa87278d 100644
--- a/fuzz/fuzz_targets/fuzz_write.rs
+++ b/fuzz/fuzz_targets/fuzz_write.rs
@@ -51,6 +51,9 @@ impl FileOperation {
 fn do_operation<T>(writer: &mut RefCell<zip_next::ZipWriter<T>>,
                    operation: &FileOperation) -> Result<(), Box<dyn std::error::Error>>
                    where T: Read + Write + Seek {
+    if zip_next::write::validate_name(&operation.get_name()).is_err() {
+        return Ok(());
+    }
     match operation {
         FileOperation::Write {file, mut options, ..} => {
             if file.contents.iter().map(Vec::len).sum::<usize>() >= u32::MAX as usize {
diff --git a/src/write.rs b/src/write.rs
index 622b39d2..7dfef832 100644
--- a/src/write.rs
+++ b/src/write.rs
@@ -439,7 +439,7 @@ impl<W: Write + Seek> ZipWriter<W> {
         {
             let header_start = self.inner.get_plain().stream_position()?;
             let name = name.into();
-            Self::validate_name(&name)?;
+            validate_name(&name)?;
 
             let permissions = options.permissions.unwrap_or(0o100644);
             let file = ZipFileData {
@@ -1032,27 +1032,30 @@ impl<W: Write + Seek> ZipWriter<W> {
         self.insert_file_data(dest_data)?;
         Ok(())
     }
-    fn validate_name(name: &String) -> ZipResult<()> {
-        for (index, _) in name.match_indices("PK") {
-            if name.len() >= index + 4 {
-                let magic_number = name[index..index + 4]
-                    .as_bytes()
-                    .read_u32::<LittleEndian>()?;
-                match magic_number {
-                    spec::ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE => {
-                        return Err(InvalidArchive("Filename can't contain ZIP64 end signature"));
-                    }
-                    spec::ZIP64_CENTRAL_DIRECTORY_END_LOCATOR_SIGNATURE => {
-                        return Err(InvalidArchive(
-                            "Filename can't contain ZIP64 end-locator signature",
-                        ));
-                    }
-                    _ => {}
+}
+
+#[cfg_attr(fuzzing, visibility::make(pub))]
+#[cfg_attr(fuzzing, allow(missing_docs))]
+pub(crate) fn validate_name(name: &String) -> ZipResult<()> {
+    for (index, _) in name.match_indices("PK") {
+        if name.len() >= index + 4 {
+            let magic_number = name[index..index + 4]
+                .as_bytes()
+                .read_u32::<LittleEndian>()?;
+            match magic_number {
+                spec::ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE => {
+                    return Err(InvalidArchive("Filename can't contain ZIP64 end signature"));
                 }
+                spec::ZIP64_CENTRAL_DIRECTORY_END_LOCATOR_SIGNATURE => {
+                    return Err(InvalidArchive(
+                        "Filename can't contain ZIP64 end-locator signature",
+                    ));
+                }
+                _ => {}
             }
         }
-        Ok(())
     }
+    Ok(())
 }
 
 impl<W: Write + Seek> Drop for ZipWriter<W> {