Fix incorrect S3 uri parsing when key is not specified on path style

src/IO/S3/URI.cpp

@@ -47,7 +47,7 @@ URI::URI(const std::string & uri_, bool allow_archive_path_syntax)
     /// Case when bucket name and key represented in the path of S3 URL.
     /// E.g. (https://s3.region.amazonaws.com/bucket-name/key)
     /// https://docs.aws.amazon.com/AmazonS3/latest/dev/VirtualHosting.html#path-style-access
-    static const RE2 path_style_pattern("^/([^/]*)/(.*)");
+    static const RE2 path_style_pattern("^/([^/]*)(?:/?(.*))");
 
     if (allow_archive_path_syntax)
         std::tie(uri_str, archive_pattern) = getURIAndArchivePattern(uri_);
@@ -124,7 +124,6 @@ URI::URI(const std::string & uri_, bool allow_archive_path_syntax)
         {
             endpoint = uri.getScheme() + "://" + name + endpoint_authority_from_uri;
         }
-        validateBucket(bucket, uri);
 
         if (!uri.getPath().empty())
         {
@@ -142,7 +141,6 @@ URI::URI(const std::string & uri_, bool allow_archive_path_syntax)
     {
         is_virtual_hosted_style = false;
         endpoint = uri.getScheme() + "://" + uri.getAuthority();
-        validateBucket(bucket, uri);
     }
     else
     {
@@ -155,6 +153,9 @@ URI::URI(const std::string & uri_, bool allow_archive_path_syntax)
         if (!uri.getPath().empty())
             key = uri.getPath().substr(1);
     }
+
+    validateBucket(bucket, uri);
+    validateKey(key, uri);
 }
 
 void URI::addRegionToURI(const std::string &region)
@@ -175,6 +176,37 @@ void URI::validateBucket(const String & bucket, const Poco::URI & uri)
             !uri.empty() ? " (" + uri.toString() + ")" : "");
 }
 
+void URI::validateKey(const String & key, const Poco::URI & uri)
+{
+    auto onError = [&]()
+    {
+        throw Exception(
+            ErrorCodes::BAD_ARGUMENTS,
+            "Invalid S3 key: {}{}",
+            quoteString(key),
+            !uri.empty() ? " (" + uri.toString() + ")" : "");
+    };
+
+
+    // this shouldn't happen ever because the regex should not catch this
+    if (key.size() == 1 && key[0] == '/')
+    {
+       onError();
+    }
+
+    // the current regex impl allows something like "bucket-name/////".
+    // bucket: bucket-name
+    // key: ////
+    // throw exception in case such thing is found
+    for (size_t i = 1; i < key.size(); i++)
+    {
+        if (key[i - 1] == '/' && key[i] == '/')
+        {
+            onError();
+        }
+    }
+}
+
 std::pair<std::string, std::optional<std::string>> URI::getURIAndArchivePattern(const std::string & source)
 {
     size_t pos = source.find("::");

src/IO/S3/URI.h

@@ -40,6 +40,7 @@ struct URI
     void addRegionToURI(const std::string & region);
 
     static void validateBucket(const std::string & bucket, const Poco::URI & uri);
+    static void validateKey(const std::string & key, const Poco::URI & uri);
 
 private:
     std::pair<std::string, std::optional<std::string>> getURIAndArchivePattern(const std::string & source);

src/IO/S3/tests/gtest_s3_uri.cpp

@@ -0,0 +1,41 @@
+#include <gtest/gtest.h>
+
+#include <IO/S3/URI.h>
+#include "config.h"
+
+
+#if USE_AWS_S3
+
+TEST(IOTestS3URI, PathStyleNoKey)
+{
+    using namespace DB;
+
+    auto uri_with_no_key_and_no_slash = S3::URI("https://s3.region.amazonaws.com/bucket-name");
+
+    ASSERT_EQ(uri_with_no_key_and_no_slash.bucket, "bucket-name");
+    ASSERT_EQ(uri_with_no_key_and_no_slash.key, "");
+
+    auto uri_with_no_key_and_with_slash = S3::URI("https://s3.region.amazonaws.com/bucket-name/");
+
+    ASSERT_EQ(uri_with_no_key_and_with_slash.bucket, "bucket-name");
+    ASSERT_EQ(uri_with_no_key_and_with_slash.key, "");
+
+    ASSERT_ANY_THROW(S3::URI("https://s3.region.amazonaws.com/bucket-name//"));
+}
+
+TEST(IOTestS3URI, PathStyleWithKey)
+{
+    using namespace DB;
+
+    auto uri_with_no_key_and_no_slash = S3::URI("https://s3.region.amazonaws.com/bucket-name/key");
+
+    ASSERT_EQ(uri_with_no_key_and_no_slash.bucket, "bucket-name");
+    ASSERT_EQ(uri_with_no_key_and_no_slash.key, "key");
+
+    auto uri_with_no_key_and_with_slash = S3::URI("https://s3.region.amazonaws.com/bucket-name/key/key/key/key");
+
+    ASSERT_EQ(uri_with_no_key_and_with_slash.bucket, "bucket-name");
+    ASSERT_EQ(uri_with_no_key_and_with_slash.key, "key/key/key/key");
+}
+
+#endif