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fix: prevent path traversal vulnerability in object handlers #2

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fix: prevent path traversal vulnerability in object handlers #2

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66 changes: 61 additions & 5 deletions src/handlers/object.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -85,7 +85,10 @@ pub async fn get_object(
None => return S3ErrorType::NoSuchBucket.to_response(Some(bucket)),
};

let path = storage.join(key.trim_start_matches('/'));
let path = match safe_join(storage, &key) {
Some(p) => p,
None => return S3ErrorType::AccessDenied.to_response(Some(key)),
};
let mut file = match File::open(&path).await {
Ok(f) => f,
Err(_) => return S3ErrorType::NoSuchKey.to_response(Some(key)),
Expand Down Expand Up @@ -161,7 +164,10 @@ pub async fn head_object(
None => return S3ErrorType::NoSuchBucket.to_response(Some(bucket)),
};

let path = storage.join(key.trim_start_matches('/'));
let path = match safe_join(storage, &key) {
Some(p) => p,
None => return S3ErrorType::AccessDenied.to_response(Some(key)),
};
let metadata = match fs::metadata(&path).await {
Ok(m) => m,
Err(_) => return S3ErrorType::NoSuchKey.to_response(Some(key)),
Expand Down Expand Up @@ -205,7 +211,10 @@ pub async fn put_object(
None => return S3ErrorType::NoSuchBucket.to_response(Some(bucket)),
};

let path = storage.join(key.trim_start_matches('/'));
let path = match safe_join(storage, &key) {
Some(p) => p,
None => return S3ErrorType::AccessDenied.to_response(Some(key)),
};

if let Some(copy_source) = headers
.get("x-amz-copy-source")
Expand Down Expand Up @@ -261,7 +270,10 @@ async fn copy_object(
None => return S3ErrorType::NoSuchBucket.to_response(Some(source_bucket)),
};

let source_path = source_storage.join(source_key.trim_start_matches('/'));
let source_path = match safe_join(source_storage, &source_key) {
Some(p) => p,
None => return S3ErrorType::AccessDenied.to_response(Some(source_key)),
};
let source_metadata = match fs::metadata(&source_path).await {
Ok(metadata) if !metadata.is_dir() => metadata,
Ok(_) => return S3ErrorType::NoSuchKey.to_response(Some(source_key)),
Expand Down Expand Up @@ -318,7 +330,10 @@ pub async fn delete_object(
None => return S3ErrorType::NoSuchBucket.to_response(Some(bucket)),
};

let path = storage.join(key.trim_start_matches('/'));
let path = match safe_join(storage, &key) {
Some(p) => p,
None => return S3ErrorType::AccessDenied.to_response(Some(key)),
};
if let Err(_) = fs::remove_file(&path).await {
// S3 returns 204 even if file doesn't exist during DELETE
return StatusCode::NO_CONTENT.into_response();
Expand Down Expand Up @@ -391,3 +406,44 @@ fn parse_copy_source(copy_source: &str) -> Option<(String, String)> {
fn owner_id() -> String {
"75aa57f09aa0c8caeab4f8c24e99d10f8e7faeebf76c078efc7c6caea54ba06a".to_string()
}

fn safe_join(storage: &std::path::Path, key: &str) -> Option<std::path::PathBuf> {
use std::path::Component;
let mut resolved = storage.to_path_buf();
for component in std::path::Path::new(key).components() {
match component {
Component::Normal(c) => resolved.push(c),
Component::RootDir | Component::CurDir => continue,
Component::Prefix(_) | Component::ParentDir => return None,
}
}
Some(resolved)
}

#[cfg(test)]
mod tests {
use super::*;
use std::path::Path;

#[test]
fn test_safe_join() {
let storage = Path::new("/var/data");

// Normal keys
assert_eq!(safe_join(storage, "my_file.txt").unwrap(), Path::new("/var/data/my_file.txt"));
assert_eq!(safe_join(storage, "folder/file.txt").unwrap(), Path::new("/var/data/folder/file.txt"));

// Leading slashes are ignored (RootDir)
assert_eq!(safe_join(storage, "/folder/file.txt").unwrap(), Path::new("/var/data/folder/file.txt"));

// Current dir dots are ignored
assert_eq!(safe_join(storage, "./folder/./file.txt").unwrap(), Path::new("/var/data/folder/file.txt"));

// ParentDir traversal is rejected
assert!(safe_join(storage, "../etc/passwd").is_none());
assert!(safe_join(storage, "folder/../../etc/passwd").is_none());

// Windows prefixes are rejected
assert!(safe_join(storage, "C:/Windows/System32").is_none());
}
}