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Fix read-tool workspace permission scoping regression (daily workflows killed by denial threshold) #49840

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Merged
pelikhan merged 4 commits into from
Aug 2, 2026
Merged

Fix read-tool workspace permission scoping regression (daily workflows killed by denial threshold) #49840

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0b738c5
Initial plan
Copilot Aug 2, 2026
24ba62d
Fix read-tool workspace permission scoping regression (#49836)
Copilot Aug 2, 2026
946ded1
Merge branch 'main' into copilot/aw-failures-fix-read-tool-permission…
github-actions[bot] Aug 2, 2026
19fa211
Fix path traversal in workspace read check using path.resolve + path.…
Copilot Aug 2, 2026
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158 changes: 136 additions & 22 deletions actions/setup/js/copilot_sdk_driver.test.cjs
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Original file line number Diff line number Diff line change
Expand Up @@ -1007,7 +1007,8 @@ describe("copilot_sdk_driver.cjs", () => {
expect(onPermissionRequest({ kind: "mcp", serverName: "github", toolName: "get_file_contents" })).toEqual({ kind: "approve-once" });
expect(onPermissionRequest({ kind: "url", url: "https://example.com" })).toEqual({ kind: "approve-once" });
expect(onPermissionRequest({ kind: "write", fileName: "a.txt", diff: "", intention: "" })).toEqual({ kind: "approve-once" });
expect(onPermissionRequest({ kind: "read", path: "a.txt", intention: "" })).toEqual({
// Reads of paths outside the workspace are denied without an explicit read grant.
expect(onPermissionRequest({ kind: "read", path: "/etc/passwd", intention: "" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
Expand Down Expand Up @@ -1215,17 +1216,97 @@ describe("copilot_sdk_driver.cjs", () => {
// Relative paths that match the pattern must still work.
expect(onPermissionRequest({ kind: "read", path: "pkg/workflow/compiler.go", intention: "" })).toEqual({ kind: "approve-once" });

// Files outside pkg/ or outside the workspace root must be denied.
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/AGENTS.md", intention: "" })).toEqual({
// Files within the workspace root are always allowed (workspace-root allowlist).
// Even files outside pkg/ must be readable since they are part of the checkout.
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/AGENTS.md", intention: "" })).toEqual({ kind: "approve-once" });
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw", intention: "" })).toEqual({ kind: "approve-once" });
// Files outside the workspace root must be denied.
expect(onPermissionRequest({ kind: "read", path: "/etc/passwd", intention: "" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
// A path outside the workspace that contains /pkg/ must not be permitted.
expect(onPermissionRequest({ kind: "read", path: "/other/workspace/pkg/workflow/file.go", intention: "" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
} finally {
if (prevWorkspace === undefined) {
delete process.env.GITHUB_WORKSPACE;
} else {
process.env.GITHUB_WORKSPACE = prevWorkspace;
}
}
});

it("always allows read of workspace root and its subdirectories for read-only workflows (regression: #49836)", async () => {
// Regression test: a workflow with only specific tool restrictions (e.g., github MCP + specific
// bash commands) must never have read($GITHUB_WORKSPACE) denied. Previously, any workflow with
// partial tool restrictions and no explicit read grant would deny workspace reads, causing
// guard.tool_denials_exceeded after 3 attempts and killing the run.
const prevWorkspace = process.env.GITHUB_WORKSPACE;
process.env.GITHUB_WORKSPACE = "/home/runner/work/gh-aw/gh-aw";
try {
const disconnect = vi.fn().mockResolvedValue(undefined);
const stop = vi.fn().mockResolvedValue(undefined);
const createSession = vi.fn().mockResolvedValue({
sessionId: "session-workspace-root-always-readable",
on: () => {},
sendAndWait: vi.fn().mockResolvedValue({ data: { content: "ok" } }),
disconnect,
});
class FakeCopilotClient {
start = vi.fn().mockResolvedValue(undefined);
createSession = createSession;
stop = stop;
}

await runWithCopilotSDK({
sdkUri: "http://127.0.0.1:3002",
prompt: "test prompt",
logger: () => {},

@github-actions github-actions Bot Aug 2, 2026

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[/tdd] The regression test for #49836 does not test the case where GITHUB_WORKSPACE is unset (i.e., logOptions.workspaceRoot is undefined). When workspaceRoot is absent, the new early-return is skipped entirely — meaning the pre-existing fallback still applies. A test confirming "when GITHUB_WORKSPACE is not set, behaviour is unchanged" would prevent future regressions where someone accidentally makes the workspace check mandatory.

💡 Suggested additional assertion 
it('falls back to prior behaviour when GITHUB_WORKSPACE is unset', async () => {
  const prevWorkspace = process.env.GITHUB_WORKSPACE;
  delete process.env.GITHUB_WORKSPACE;
  try {
    const handler = await makePermissionHandlerViaSDK(['shell(ls)']);
    // Without a workspace root, workspace-path reads are still denied (no regression in fallback).
    expect(handler({ kind: 'read', path: '/home/runner/work/gh-aw/gh-aw/AGENTS.md' })).toEqual({
      kind: 'reject',
      feedback: 'Tool invocation is not allowed by workflow tool permissions.',
    });
  } finally {
    if (prevWorkspace === undefined) delete process.env.GITHUB_WORKSPACE;
    else process.env.GITHUB_WORKSPACE = prevWorkspace;
  }
});

This pins the contract: the early-return is only active when workspaceRoot is provided.

@copilot please address this.

// Read-only workflow: only github MCP + restricted bash, no explicit read grant.
permissionConfig: {
allowedTools: ["github", 'shell(find . -name "*_test.go" -type f)', "shell(cat **/*_test.go)", 'shell(grep -r "func Test" . --include="*_test.go")', "shell(go test -v ./...)", "shell(wc -l **/*_test.go)", "shell(gh:*)"],
},
sdkModule: {
CopilotClient: FakeCopilotClient,
RuntimeConnection: { forUri: vi.fn(() => ({})) },
approveAll: () => ({ kind: "approve-once" }),
},
});

const sessionConfig = createSession.mock.calls[0][0];
const onPermissionRequest = sessionConfig.onPermissionRequest;

// The workspace root itself must always be readable.
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw", intention: "" })).toEqual({ kind: "approve-once" });
// Any subdirectory under the workspace must be readable.
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/pkg/workflow", intention: "" })).toEqual({ kind: "approve-once" });
// Any file under the workspace must be readable.
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/AGENTS.md", intention: "" })).toEqual({ kind: "approve-once" });
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/pkg/workflow/copilot_engine_tools.go", intention: "" })).toEqual({ kind: "approve-once" });

// Relative paths must be resolved inside the workspace and approved.
expect(onPermissionRequest({ kind: "read", path: "AGENTS.md", intention: "" })).toEqual({ kind: "approve-once" });
expect(onPermissionRequest({ kind: "read", path: "pkg/workflow/file.go", intention: "" })).toEqual({ kind: "approve-once" });

// Path traversal attempts must be rejected even when they start with the workspace prefix.
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/../../../../etc/passwd", intention: "" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/../../../other-repo/secret.txt", intention: "" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});

// Paths outside the workspace root must still be denied.
expect(onPermissionRequest({ kind: "read", path: "/etc/passwd", intention: "" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
// A path outside the workspace that contains /pkg/ must not be permitted.
expect(onPermissionRequest({ kind: "read", path: "/other/workspace/pkg/workflow/file.go", intention: "" })).toEqual({
expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/other-repo/secret.txt", intention: "" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
Expand Down Expand Up @@ -1801,24 +1882,57 @@ for f in $FILES; do wc -l "/home/runner/work/gh-aw/gh-aw/pkg/workflow/$f"; done`
expect(result).toEqual({ kind: "approve-once" });
});

it("requires explicit read permission for AGENTS.md and SKILL.md reads", async () => {
const denied = await makePermissionHandlerViaSDK(["shell(ls)"]);
expect(denied({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/AGENTS.md" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
expect(denied({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/SKILL.md" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
it("workspace files are always readable; only non-workspace paths require explicit read permission", async () => {
// Regression fix (#49836): workspace root and its contents are always readable regardless
// of tool restrictions. Only paths outside GITHUB_WORKSPACE require an explicit read grant.
const prevWorkspace = process.env.GITHUB_WORKSPACE;
process.env.GITHUB_WORKSPACE = "/home/runner/work/gh-aw/gh-aw";
try {
const deniedOutsideWorkspace = await makePermissionHandlerViaSDK(["shell(ls)"]);
// Files inside the workspace are always readable — no explicit grant needed.
expect(deniedOutsideWorkspace({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/AGENTS.md" })).toEqual({
kind: "approve-once",
});
expect(deniedOutsideWorkspace({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/SKILL.md" })).toEqual({
kind: "approve-once",
});
// Relative paths must be resolved inside the workspace and approved.
expect(deniedOutsideWorkspace({ kind: "read", path: "AGENTS.md" })).toEqual({
kind: "approve-once",
});
expect(deniedOutsideWorkspace({ kind: "read", path: "pkg/workflow/file.go" })).toEqual({
kind: "approve-once",
});
// Path traversal attempts must be rejected even when they start with the workspace prefix.
expect(deniedOutsideWorkspace({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/../../../../etc/passwd" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
// Files outside the workspace still require an explicit read grant.
expect(deniedOutsideWorkspace({ kind: "read", path: "/etc/passwd" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});
expect(deniedOutsideWorkspace({ kind: "read", path: "/home/runner/other-repo/secret.txt" })).toEqual({
kind: "reject",
feedback: "Tool invocation is not allowed by workflow tool permissions.",
});

const allowed = await makePermissionHandlerViaSDK(["read"]);
expect(allowed({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/AGENTS.md" })).toEqual({
kind: "approve-once",
});
expect(allowed({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/SKILL.md" })).toEqual({
kind: "approve-once",
});
const allowed = await makePermissionHandlerViaSDK(["read"]);
// With an explicit read grant, all paths are readable.
expect(allowed({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/AGENTS.md" })).toEqual({
kind: "approve-once",
});
expect(allowed({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/SKILL.md" })).toEqual({
kind: "approve-once",
});
} finally {
if (prevWorkspace === undefined) {
delete process.env.GITHUB_WORKSPACE;
} else {
process.env.GITHUB_WORKSPACE = prevWorkspace;
}
}
});

it("denies issue-37538 commands when workflow only allows jq shell usage", async () => {
Expand Down
15 changes: 15 additions & 0 deletions actions/setup/js/copilot_sdk_permissions.cjs
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Original file line number Diff line number Diff line change
Expand Up @@ -352,6 +352,21 @@ function buildCopilotSDKPermissionHandler(permissionConfig, approveAll, logOptio
return allowedToolEntries.has("write");
case "read":
// Any read grant (read, read(...), read:*) is path-agnostic in Copilot SDK.
// Always allow reads for paths at or under the workspace root (GITHUB_WORKSPACE).
// Every workflow runs inside its own checkout and must be able to read its source tree
// regardless of any narrower tool-permission scoping configured elsewhere.
//
// Use path.resolve + path.relative for containment rather than a string-prefix check so
// that ".." traversal paths (e.g. workspace/../../../../etc/passwd) are rejected and
// relative paths (e.g. "AGENTS.md") are correctly resolved inside the workspace.
if (logOptions?.workspaceRoot && typeof request.path === "string" && request.path.length > 0) {
const resolvedWorkspace = path.resolve(logOptions.workspaceRoot);
const resolvedPath = path.isAbsolute(request.path) ? path.resolve(request.path) : path.resolve(resolvedWorkspace, request.path);
const rel = path.relative(resolvedWorkspace, resolvedPath);
if (rel === "" || (!rel.startsWith("..") && !path.isAbsolute(rel))) {
return true;

@github-actions github-actions Bot Aug 2, 2026

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Security: path-traversal bypass — workspace containment check can be defeated with ../ segments

normalizePermissionPath only strips trailing slashes and normalizes backslashes; it does not resolve .. components. A crafted path like /home/runner/work/gh-aw/gh-aw/../../../etc/passwd passes normalizePermissionPath unchanged and still starts with the workspace prefix, so the early return true fires for a file well outside the checkout.

// Proof
normalizePermissionPath("/home/runner/work/gh-aw/gh-aw/../../../etc/passwd")
// → "/home/runner/work/gh-aw/gh-aw/../../../etc/passwd"
// .startsWith("/home/runner/work/gh-aw/gh-aw/") === true  ← incorrectly approved

Fix: resolve both paths with path.posix.normalize before the prefix check so .. segments are collapsed:

const { posix } = require("path");
// inside case "read":
if (logOptions?.workspaceRoot && typeof request.path === "string" && request.path.length > 0) {
  const normalizedWorkspace = posix.normalize(normalizePermissionPath(logOptions.workspaceRoot));
  const normalizedPath = posix.normalize(normalizePermissionPath(request.path));
  if (normalizedPath === normalizedWorkspace || normalizedPath.startsWith(normalizedWorkspace + "/")) {
    return true;
  }
}

Add a corresponding test case:

expect(onPermissionRequest({ kind: "read", path: "/home/runner/work/gh-aw/gh-aw/../../../etc/passwd", intention: "" }))
  .toEqual({ kind: "reject", feedback: "Tool invocation is not allowed by workflow tool permissions." });

@copilot please address this.

}
}
return hasReadGrant || allowedToolEntries.has("shell") || isReadPathAllowedByShellRules(request.path, readablePathPatterns, logOptions?.workspaceRoot);
case "url":
return allowedToolEntries.has("web_fetch");
Expand Down
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