Initial commit: ArchStore package manager for Arch Linux

backend/utils/sanitize.py

@@ -0,0 +1,69 @@
+"""
+Sanitization utilities for ArchStore.
+Prevents command injection and validates all user-supplied input
+before it reaches any shell command.
+"""
+
+import re
+
+# Strict whitelist: only allow valid package name characters
+# Arch package names: lowercase letters, digits, @, ., _, +, -
+PACKAGE_NAME_PATTERN = re.compile(r'^[a-zA-Z0-9@._+\-]+$')
+
+# Maximum lengths
+MAX_PACKAGE_NAME_LENGTH = 256
+MAX_SEARCH_QUERY_LENGTH = 128
+
+
+def sanitize_package_name(name: str) -> str:
+    """
+    Validate and sanitize a package name.
+    Raises ValueError if the name contains invalid characters.
+    """
+    if not name or not isinstance(name, str):
+        raise ValueError("Package name cannot be empty")
+
+    name = name.strip()
+
+    if len(name) > MAX_PACKAGE_NAME_LENGTH:
+        raise ValueError(f"Package name too long (max {MAX_PACKAGE_NAME_LENGTH} chars)")
+
+    if not PACKAGE_NAME_PATTERN.match(name):
+        raise ValueError(
+            f"Invalid package name '{name}'. "
+            "Only letters, digits, @, ., _, +, - are allowed."
+        )
+
+    return name
+
+
+def sanitize_search_query(query: str) -> str:
+    """
+    Validate and sanitize a search query.
+    More permissive than package names but still safe.
+    """
+    if not query or not isinstance(query, str):
+        raise ValueError("Search query cannot be empty")
+
+    query = query.strip()
+
+    if len(query) > MAX_SEARCH_QUERY_LENGTH:
+        raise ValueError(f"Search query too long (max {MAX_SEARCH_QUERY_LENGTH} chars)")
+
+    # Remove any shell metacharacters
+    dangerous_chars = set(';&|`$(){}[]!#~\\<>"\'\n\r\t')
+    sanitized = ''.join(c for c in query if c not in dangerous_chars)
+
+    if not sanitized:
+        raise ValueError("Search query contains only invalid characters")
+
+    return sanitized
+
+
+def validate_source_filter(source: str) -> str:
+    """Validate the source filter parameter."""
+    allowed = {"all", "pacman", "aur"}
+    source = source.strip().lower()
+    if source not in allowed:
+        raise ValueError(f"Invalid source filter '{source}'. Allowed: {', '.join(allowed)}")
+    return source