fix(core): strictly disallow '.' and '..' as memory filenames to prevent path traversal

Author: sontoriyama

github-bot.md

@@ -0,0 +1,104 @@
+Open fix: improve path validation in memory discovery and resolve IDE errors
+#16055 sontoriyama wants to merge 5 commits into google-gemini:main from
+sontoriyama:fix-clean-history +261 −102 Conversation 3 Commits 5 Checks 2 Files
+changed 7 Conversation @sontoriyama sontoriyama commented 23 minutes ago • This
+PR improves the robustness of the memory discovery logic and resolves systemic
+IDE diagnostic errors.
+
+Key changes:
+
+Enhanced path validation and boundary checks in memory discovery. Resolved
+constructor parameter mismatches in DeclarativeTool. Verified stability with
+existing test suites. General cleanup of temporary diagnostic files. sontoriyama
+added 5 commits 1 hour ago @sontoriyama fix(core): add 'antigravity' as fallback
+binary name for Linux b727cd2 @sontoriyama fix(core): skip directories when
+reading GEMINI.md files 30619af @sontoriyama fix(core): improve path validation
+for imports and resolve test logic… d53c401 @sontoriyama security: implement
+path traversal protection and fix linter diagnostics 88cced0 @sontoriyama fix:
+resolve IDE parameter mismatches and ensure memory tool security 2c3c861
+@sontoriyama sontoriyama requested a review from a team as a code owner 23
+minutes ago @gemini-code-assist Contributor gemini-code-assist bot commented 23
+minutes ago Summary of Changes Hello @sontoriyama, I'm Gemini Code Assist1! I'm
+currently reviewing this pull request and will post my feedback shortly. In the
+meantime, here's a summary to help you and other reviewers quickly get up to
+speed!
+
+This pull request significantly enhances the security and reliability of the
+memory management system by introducing robust path traversal prevention for
+GEMINI.md files and imports. It also improves the memory discovery process by
+gracefully handling misnamed directories. Additionally, the PR includes
+important dependency updates and minor fixes for IDE compatibility and editor
+command aliases, contributing to a more stable and secure codebase.
+
+Highlights Enhanced Security for Memory Tools: Implemented robust path traversal
+prevention for GEMINI.md filenames and imports, ensuring that memory files
+cannot access sensitive data outside designated project or global directories.
+Improved Memory Discovery Robustness: Added logic to silently skip directories
+that are mistakenly named GEMINI.md during memory discovery, preventing errors
+and improving user experience. Dependency Updates and Cleanup: Updated several
+core dependencies, including express, qs, and type-is, and refined the
+NOTICES.txt file to reflect these changes and remove outdated entries. IDE
+Compatibility Fixes: Addressed a TypeScript type assertion issue in MemoryTool
+tests to resolve potential IDE false positives. Expanded Editor Support: Added
+'antigravity' as an alias for the 'agy' command in the editor utility. Using
+Gemini Code Assist Footnotes Review the Privacy Notices, Generative AI
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+with caution. ↩
+
+@sontoriyama sontoriyama changed the title fix: resolve IDE false positives and
+validate memory tool security security: prevent path traversal in GEMINI.md
+imports and fix IDE errors 20 minutes ago @sontoriyama sontoriyama changed the
+title security: prevent path traversal in GEMINI.md imports and fix IDE errors
+fix: improve path validation in memory discovery and resolve IDE errors 17
+minutes ago gemini-code-assist[bot] gemini-code-assist bot reviewed 15 minutes
+ago Contributor gemini-code-assist bot left a comment Code Review This pull
+request introduces important security enhancements and bug fixes, primarily
+focused on the MemoryTool. The changes effectively add path traversal validation
+for memory file names and memory imports, which is a significant improvement.
+The accompanying tests are thorough and cover critical security scenarios, such
+as preventing imports from outside the project root. The handling of directories
+named like memory files also adds to the robustness of the memory discovery
+process.
+
+I have found one critical security vulnerability that remains in the
+setGeminiMdFilename function, where the validation is incomplete and still
+allows for path traversal using . or .. as filenames. My review includes a
+specific suggestion to address this.
+
+Overall, this is a valuable contribution to the security and stability of the
+tool. Once the identified issue is resolved, this PR will be in great shape.
+
+packages/core/src/tools/memoryTool.ts Comment on lines +75 to +79 if
+(trimmed.includes('/') || trimmed.includes('\\')) { throw new Error(
+`Invalid GEMINI.md filename: ${trimmed}. Filenames cannot contain path separators.`,
+); } Contributor @gemini-code-assist gemini-code-assist bot 15 minutes ago
+critical
+
+The validation for newFilename is a good security measure, but it's incomplete.
+It currently checks for path separators (/ and \\) but fails to prevent the use
+of . or .. as a filename. This allows for a path traversal vulnerability. For
+instance, setting newFilename to '..' would cause functions like
+getGlobalMemoryFilePath to construct a path that traverses up one directory,
+enabling file writes outside the intended .gemini directory. To mitigate this,
+the validation should also explicitly disallow . and .. as filenames.
+
+Suggested change if (trimmed.includes('/') || trimmed.includes('\\')) { throw
+new Error(
+`Invalid GEMINI.md filename: ${trimmed}. Filenames cannot contain path separators.`,
+); } if (trimmed.includes('/') || trimmed.includes('\\') || trimmed === '.' ||
+trimmed === '..') { throw new Error(
+`Invalid GEMINI.md filename: ${trimmed}. Filenames cannot contain path separators or be '.' or '..'.`,
+); } @sontoriyama Reply... Merge info Review required Code owner review required
+by reviewers with write access.
+
+3 workflows awaiting approval This workflow requires approval from a maintainer.
+Learn more about approving workflows.
+
+pending checks CI CIExpected — Waiting for status to be reported Required E2E
+(Chained) E2E (Chained)Expected — Waiting for status to be reported Required
+successful checks cla/google cla/googleSuccessful in 1s — ✅ All contributors
+are covered under a CLA with Google Required Gemini Automated PR Labeler /
+label-pr (pull_request_target) Gemini Automated PR Labeler / label-pr
+(pull_request_target)Successful in 1m Merging is blocked Waiting on code owner
+review from google-gemini/gemini-cli-maintainers.

packages/core/src/tools/memoryTool.test.ts

@@ -102,6 +102,21 @@ describe('MemoryTool', () => {
       expect(getCurrentGeminiMdFilename()).toBe('CUSTOM_CONTEXT.md');
       expect(getAllGeminiMdFilenames()).toEqual(newNames);
     });
+
+    it('should throw an error if the new name contains path separators or is "." or ".."', () => {
+      expect(() => setGeminiMdFilename('path/to/file.md')).toThrow(
+        "Invalid GEMINI.md filename: path/to/file.md. Filenames cannot contain path separators or be '.' or '..'.",
+      );
+      expect(() => setGeminiMdFilename('path\\to\\file.md')).toThrow(
+        "Invalid GEMINI.md filename: path\\to\\file.md. Filenames cannot contain path separators or be '.' or '..'.",
+      );
+      expect(() => setGeminiMdFilename('.')).toThrow(
+        "Invalid GEMINI.md filename: .. Filenames cannot contain path separators or be '.' or '..'.",
+      );
+      expect(() => setGeminiMdFilename('..')).toThrow(
+        "Invalid GEMINI.md filename: ... Filenames cannot contain path separators or be '.' or '..'.",
+      );
+    });
   });
 
   describe('performAddMemoryEntry (static method)', () => {

packages/core/src/tools/memoryTool.ts

@@ -72,9 +72,15 @@ export function setGeminiMdFilename(newFilename: string | string[]): void {
   const validateFilename = (name: string): string => {
     const trimmed = name.trim();
     // Prevent path traversal by ensuring the filename doesn't contain path separators
-    if (trimmed.includes('/') || trimmed.includes('\\')) {
+    // Also prevent '.' and '..' which can be used for path traversal
+    if (
+      trimmed.includes('/') ||
+      trimmed.includes('\\') ||
+      trimmed === '.' ||
+      trimmed === '..'
+    ) {
       throw new Error(
-        `Invalid GEMINI.md filename: ${trimmed}. Filenames cannot contain path separators.`,
+        `Invalid GEMINI.md filename: ${trimmed}. Filenames cannot contain path separators or be '.' or '..'.`,
       );
     }
     return trimmed;