SNOW-2011595 Masking filter introduced on library levels (#2253)

Author: sfc-gh-fpawlowski

.github/workflows/build_test.yml

@@ -20,7 +20,7 @@ on:
             description: "Test scenario tags"
 
 concurrency:
-  # older builds for the same pull request numer or branch should be cancelled
+  # older builds for the same pull request number or branch should be cancelled
   cancel-in-progress: true
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
 

DESCRIPTION.md

@@ -21,6 +21,7 @@ Source code is also available at: https://github.com/snowflakedb/snowflake-conne
   - Added `check_arrow_conversion_error_on_every_column` connection property that can be set to `False` to restore previous behaviour in which driver will ignore errors until it occurs in the last column. This flag's purpose is to unblock workflows that may be impacted by the bugfix and will be removed in later releases.
   - Lower log levels from info to debug for some of the messages to make the output easier to follow.
   - Allow the connector to inherit a UUID4 generated upstream, provided in statement parameters (field: `requestId`), rather than automatically generate a UUID4 to use for the HTTP Request ID.
+  - Improved logging in urllib3, boto3, botocore - assured data masking even after migration to the external owned library in the future.
   - Fix expired S3 credentials update and increment retry when expired credentials are found.
   - Added `client_fetch_threads` experimental parameter to better utilize threads for fetching query results.
 

src/snowflake/connector/__init__.py

@@ -12,6 +12,8 @@
 import logging
 from logging import NullHandler
 
+from snowflake.connector.externals_utils.externals_setup import setup_external_libraries
+
 from .connection import SnowflakeConnection
 from .cursor import DictCursor
 from .dbapi import (
@@ -44,6 +46,7 @@
 from .version import VERSION
 
 logging.getLogger(__name__).addHandler(NullHandler())
+setup_external_libraries()
 
 
 @wraps(SnowflakeConnection.__init__)

src/snowflake/connector/azure_storage_client.py

@@ -5,7 +5,7 @@
 import os
 import xml.etree.ElementTree as ET
 from datetime import datetime, timezone
-from logging import Filter, getLogger
+from logging import getLogger
 from random import choice
 from string import hexdigits
 from typing import TYPE_CHECKING, Any, NamedTuple
@@ -37,22 +37,6 @@ class AzureLocation(NamedTuple):
 MATDESC = "x-ms-meta-matdesc"
 
 
-class AzureCredentialFilter(Filter):
-    LEAKY_FMT = '%s://%s:%s "%s %s %s" %s %s'
-
-    def filter(self, record):
-        if record.msg == AzureCredentialFilter.LEAKY_FMT and len(record.args) == 8:
-            record.args = (
-                record.args[:4] + (record.args[4].split("?")[0],) + record.args[5:]
-            )
-        return True
-
-
-getLogger("snowflake.connector.vendored.urllib3.connectionpool").addFilter(
-    AzureCredentialFilter()
-)
-
-
 class SnowflakeAzureRestClient(SnowflakeStorageClient):
     def __init__(
         self,

src/snowflake/connector/cursor.py

@@ -910,8 +910,8 @@ def execute(
             _exec_async: Whether to execute this query asynchronously.
             _no_retry: Whether or not to retry on known errors.
             _do_reset: Whether or not the result set needs to be reset before executing query.
-            _put_callback: Function to which GET command should call back to.
-            _put_azure_callback: Function to which an Azure GET command should call back to.
+            _put_callback: Function to which PUT command should call back to.
+            _put_azure_callback: Function to which an Azure PUT command should call back to.
             _put_callback_output_stream: The output stream a PUT command's callback should report on.
             _get_callback: Function to which GET command should call back to.
             _get_azure_callback: Function to which an Azure GET command should call back to.

src/snowflake/connector/externals_utils/__init__.py

@@ -0,0 +1,27 @@
+from __future__ import annotations
+
+from snowflake.connector.logging_utils.filters import (
+    SecretMaskingFilter,
+    add_filter_to_logger_and_children,
+)
+
+MODULES_TO_MASK_LOGS_NAMES = [
+    "snowflake.connector.vendored.urllib3",
+    "botocore",
+    "boto3",
+]
+# TODO: after migration to the external urllib3 from the vendored one (SNOW-2041970),
+#  we should change filters here immediately to the below module's logger:
+#  MODULES_TO_MASK_LOGS_NAMES = [ "urllib3", ... ]
+
+
+def add_filters_to_external_loggers():
+    for module_name in MODULES_TO_MASK_LOGS_NAMES:
+        add_filter_to_logger_and_children(module_name, SecretMaskingFilter())
+
+
+def setup_external_libraries():
+    """
+    Assures proper setup and injections before any external libraries are used.
+    """
+    add_filters_to_external_loggers()

src/snowflake/connector/externals_utils/externals_setup.py

@@ -0,0 +1,72 @@
+from __future__ import annotations
+
+import logging
+
+from snowflake.connector.secret_detector import SecretDetector
+
+
+def add_filter_to_logger_and_children(
+    base_logger_name: str, filter_instance: logging.Filter
+) -> None:
+    # Ensure the base logger exists and apply filter
+    base_logger = logging.getLogger(base_logger_name)
+    if filter_instance not in base_logger.filters:
+        base_logger.addFilter(filter_instance)
+
+    all_loggers_pairs = logging.root.manager.loggerDict.items()
+    for name, obj in all_loggers_pairs:
+        if not name.startswith(base_logger_name + "."):
+            continue
+
+        if not isinstance(obj, logging.Logger):
+            continue  # Skip placeholders
+
+        if filter_instance not in obj.filters:
+            obj.addFilter(filter_instance)
+
+
+class SecretMaskingFilter(logging.Filter):
+    """
+    A logging filter that masks sensitive information in log messages using the SecretDetector utility.
+
+    This filter is designed for scenarios where you want to avoid applying SecretDetector globally
+    as a formatter on all logging handlers. Global masking can introduce unnecessary computational
+    overhead, particularly for internal logs where secrets are already handled explicitly.
+    It would be also easy to bypass unintentionally by simply adding a neighbouring handler to a logger
+    - without SecretDetector set as a formatter.
+
+    On the other hand, libraries or submodules often do not have any handler attached, so formatting can't be
+    configured on those level, while attaching new handler for that can cause unintended log output or its duplication.
+
+    ⚠ Important:
+        - Logging filters do **not** propagate down the logger hierarchy.
+          To apply this filter across a hierarchy, use the `add_filter_to_logger_and_children` utility.
+        - This filter causes **early formatting** of the log message (`record.getMessage()`),
+          meaning `record.args` are merged into `record.msg` prematurely.
+          If you rely on `record.args`, ensure this is the **last** filter in the chain.
+
+    Notes:
+        - The filter directly modifies `record.msg` with the masked version of the message.
+        - It clears `record.args` to prevent re-formatting and ensure safe message output.
+
+    Example:
+        logger.addFilter(SecretMaskingFilter())
+        handler.addFilter(SecretMaskingFilter())
+    """
+
+    def filter(self, record: logging.LogRecord) -> bool:
+        try:
+            # Format the message as it would be
+            message = record.getMessage()
+
+            # Run masking on the whole message
+            masked_data = SecretDetector.mask_secrets(message)
+            record.msg = masked_data.masked_text
+        except Exception as ex:
+            record.msg = SecretDetector.create_formatting_error_log(
+                record, "EXCEPTION - " + str(ex)
+            )
+        finally:
+            record.args = ()  # Avoid format re-application of formatting
+
+        return True  # allow all logs through

src/snowflake/connector/logging_utils/__init__.py

@@ -10,11 +10,18 @@
 import logging
 import os
 import re
+from typing import NamedTuple
 
 MIN_TOKEN_LEN = os.getenv("MIN_TOKEN_LEN", 32)
 MIN_PWD_LEN = os.getenv("MIN_PWD_LEN", 8)
 
 
+class MaskedMessageData(NamedTuple):
+    is_masked: bool = False
+    masked_text: str | None = None
+    error_str: str | None = None
+
+
 class SecretDetector(logging.Formatter):
     AWS_KEY_PATTERN = re.compile(
         r"(aws_key_id|aws_secret_key|access_key_id|secret_access_key)\s*=\s*'([^']+)'",
@@ -48,21 +55,31 @@ class SecretDetector(logging.Formatter):
         flags=re.IGNORECASE,
     )
 
+    SECRET_STARRED_MASK_STR = "****"
+
     @staticmethod
     def mask_connection_token(text: str) -> str:
-        return SecretDetector.CONNECTION_TOKEN_PATTERN.sub(r"\1\2****", text)
+        return SecretDetector.CONNECTION_TOKEN_PATTERN.sub(
+            r"\1\2" + f"{SecretDetector.SECRET_STARRED_MASK_STR}", text
+        )
 
     @staticmethod
     def mask_password(text: str) -> str:
-        return SecretDetector.PASSWORD_PATTERN.sub(r"\1\2****", text)
+        return SecretDetector.PASSWORD_PATTERN.sub(
+            r"\1\2" + f"{SecretDetector.SECRET_STARRED_MASK_STR}", text
+        )
 
     @staticmethod
     def mask_aws_keys(text: str) -> str:
-        return SecretDetector.AWS_KEY_PATTERN.sub(r"\1='****'", text)
+        return SecretDetector.AWS_KEY_PATTERN.sub(
+            r"\1=" + f"'{SecretDetector.SECRET_STARRED_MASK_STR}'", text
+        )
 
     @staticmethod
     def mask_sas_tokens(text: str) -> str:
-        return SecretDetector.SAS_TOKEN_PATTERN.sub(r"\1=****", text)
+        return SecretDetector.SAS_TOKEN_PATTERN.sub(
+            r"\1=" + f"{SecretDetector.SECRET_STARRED_MASK_STR}", text
+        )
 
     @staticmethod
     def mask_aws_tokens(text: str) -> str:
@@ -81,17 +98,17 @@ def mask_private_key_data(text: str) -> str:
         )
 
     @staticmethod
-    def mask_secrets(text: str) -> tuple[bool, str, str | None]:
+    def mask_secrets(text: str) -> MaskedMessageData:
         """Masks any secrets. This is the method that should be used by outside classes.
 
         Args:
             text: A string which may contain a secret.
 
         Returns:
-            The masked string.
+            The masked string data in MaskedMessageData.
         """
         if text is None:
-            return (False, None, None)
+            return MaskedMessageData()
 
         masked = False
         err_str = None
@@ -119,7 +136,20 @@ def mask_secrets(text: str) -> tuple[bool, str, str | None]:
             masked_text = str(ex)
             err_str = str(ex)
 
-        return masked, masked_text, err_str
+        return MaskedMessageData(masked, masked_text, err_str)
+
+    @staticmethod
+    def create_formatting_error_log(
+        original_record: logging.LogRecord, error_message: str
+    ) -> str:
+        return "{} - {} {} - {} - {} - {}".format(
+            original_record.asctime,
+            original_record.threadName,
+            "secret_detector.py",
+            "sanitize_log_str",
+            original_record.levelname,
+            error_message,
+        )
 
     def format(self, record: logging.LogRecord) -> str:
         """Wrapper around logging module's formatter.
@@ -134,25 +164,18 @@ def format(self, record: logging.LogRecord) -> str:
         """
         try:
             unsanitized_log = super().format(record)
-            masked, sanitized_log, err_str = SecretDetector.mask_secrets(
+            masked, optional_sanitized_log, err_str = SecretDetector.mask_secrets(
                 unsanitized_log
             )
+            # Added to comply with type hints (Optional[str] is not accepted for str)
+            sanitized_log = optional_sanitized_log or ""
+
             if masked and err_str is not None:
-                sanitized_log = "{} - {} {} - {} - {} - {}".format(
-                    record.asctime,
-                    record.threadName,
-                    "secret_detector.py",
-                    "sanitize_log_str",
-                    record.levelname,
-                    err_str,
-                )
+                sanitized_log = self.create_formatting_error_log(record, err_str)
+
         except Exception as ex:
-            sanitized_log = "{} - {} {} - {} - {} - {}".format(
-                record.asctime,
-                record.threadName,
-                "secret_detector.py",
-                "sanitize_log_str",
-                record.levelname,
-                "EXCEPTION - " + str(ex),
+            sanitized_log = self.create_formatting_error_log(
+                record, "EXCEPTION - " + str(ex)
             )
+
         return sanitized_log