refactor(standalone): add asRoot parameter to execInContainer #513

doringeman · 2025-12-15T10:27:34Z

Require callers to explicitly opt-in to root privileges when executing commands in containers. This avoids running all execs as root, which could violate security expectations for containers that define a non-root default user.

Based on #511 (comment).

Require callers to explicitly opt-in to root privileges when executing commands in containers. This avoids running all execs as root, which could violate security expectations for containers that define a non-root default user. Signed-off-by: Dorin Geman <[email protected]>

gemini-code-assist · 2025-12-15T10:27:49Z

Summary of Changes

Hello @doringeman, 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 introduces a significant security enhancement by modifying the execInContainer function to require explicit opt-in for root privileges. This change ensures that commands executed within containers default to a non-root user, preventing unintended root execution and improving the overall security posture of container operations.

Highlights

Refactored execInContainer function: The execInContainer function now includes an asRoot boolean parameter, requiring callers to explicitly opt-in for root privileges when executing commands within a container.
Default non-root execution: The default behavior of execInContainer has been changed so that commands are no longer run as root by default, enhancing security by aligning with container best practices.
Updated existing calls: All existing calls to execInContainer have been updated to pass the new asRoot parameter. Commands related to Docker configuration (e.g., mkdir, chown, chmod) now explicitly run as non-root, while update-ca-certificates explicitly runs as root.

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Code Review

This pull request introduces a beneficial security enhancement by refactoring execInContainer to require an explicit asRoot parameter, preventing commands from running with root privileges by default. The implementation of this change is sound. However, I've identified two instances where this new parameter is used incorrectly in copyDockerConfigToContainer. The commands being executed require root privileges because they use chown, but they are called with asRoot: false. This will lead to errors in containers with a non-root default user. My review provides specific suggestions to correct these calls.

gemini-code-assist · 2025-12-15T10:28:48Z

cmd/cli/pkg/standalone/containers.go

 	// Ensure the .docker directory exists
 	mkdirCmd := "mkdir -p /home/modelrunner/.docker && chown modelrunner:modelrunner /home/modelrunner/.docker"
-	if err := execInContainer(ctx, dockerClient, containerID, mkdirCmd); err != nil {
+	if err := execInContainer(ctx, dockerClient, containerID, mkdirCmd, false); err != nil {


The mkdirCmd includes a chown command, which requires root privileges to execute. With asRoot set to false, this command will fail if the container's default user is not root. To ensure the directory ownership can be set as intended, this command should be executed with root privileges.

Suggested change

if err := execInContainer(ctx, dockerClient, containerID, mkdirCmd, false); err != nil {

if err := execInContainer(ctx, dockerClient, containerID, mkdirCmd, true); err != nil {

gemini-code-assist · 2025-12-15T10:28:48Z

cmd/cli/pkg/standalone/containers.go

 	// Set correct ownership and permissions
 	chmodCmd := "chown modelrunner:modelrunner /home/modelrunner/.docker/config.json && chmod 600 /home/modelrunner/.docker/config.json"
-	if err := execInContainer(ctx, dockerClient, containerID, chmodCmd); err != nil {
+	if err := execInContainer(ctx, dockerClient, containerID, chmodCmd, false); err != nil {


Similar to the command for creating the directory, this chmodCmd also includes chown, which requires root privileges. Setting asRoot to false will cause this command to fail if the container is not running as root. To ensure the file's ownership and permissions are correctly set, this should be run as root.

Suggested change

if err := execInContainer(ctx, dockerClient, containerID, chmodCmd, false); err != nil {

if err := execInContainer(ctx, dockerClient, containerID, chmodCmd, true); err != nil {

sourcery-ai

Hey there - I've reviewed your changes and they look great!

Prompt for AI Agents

Please address the comments from this code review:

## Individual Comments

### Comment 1
<location> `cmd/cli/pkg/standalone/containers.go:71-74` </location>
<code_context>
 	// Ensure the .docker directory exists
 	mkdirCmd := "mkdir -p /home/modelrunner/.docker && chown modelrunner:modelrunner /home/modelrunner/.docker"
-	if err := execInContainer(ctx, dockerClient, containerID, mkdirCmd); err != nil {
+	if err := execInContainer(ctx, dockerClient, containerID, mkdirCmd, false); err != nil {
 		return err
 	}
</code_context>

<issue_to_address>
**issue (bug_risk):** Running chown/chmod without root is likely to fail and silently change behavior compared to the previous implementation.

Before this change, `execInContainer` always ran as root, so these `chown`/`chmod` calls would normally succeed. With `asRoot` now set to `false`, they run as the container’s default user, and `chown` (and sometimes `chmod` on root-owned paths) will often fail without error handling for permission issues. Please either run these commands with `asRoot = true` or rework the ownership/permission handling so it doesn’t depend on root, to avoid a behavioral regression that only shows up on some environments.
</issue_to_address>

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sourcery-ai · 2025-12-15T10:29:02Z

cmd/cli/pkg/standalone/containers.go

+	if err := execInContainer(ctx, dockerClient, containerID, mkdirCmd, false); err != nil {
 		return err
 	}



issue (bug_risk): Running chown/chmod without root is likely to fail and silently change behavior compared to the previous implementation.

Before this change, execInContainer always ran as root, so these chown/chmod calls would normally succeed. With asRoot now set to false, they run as the container’s default user, and chown (and sometimes chmod on root-owned paths) will often fail without error handling for permission issues. Please either run these commands with asRoot = true or rework the ownership/permission handling so it doesn’t depend on root, to avoid a behavioral regression that only shows up on some environments.

ilopezluna

thanks!

doringeman requested a review from ilopezluna December 15, 2025 10:27

gemini-code-assist bot reviewed Dec 15, 2025

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sourcery-ai bot reviewed Dec 15, 2025

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ilopezluna approved these changes Dec 15, 2025

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doringeman merged commit 3ac8e33 into docker:main Dec 15, 2025
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refactor(standalone): add asRoot parameter to execInContainer #513

refactor(standalone): add asRoot parameter to execInContainer #513

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	if err := execInContainer(ctx, dockerClient, containerID, mkdirCmd, false); err != nil {
	if err := execInContainer(ctx, dockerClient, containerID, mkdirCmd, true); err != nil {

refactor(standalone): add asRoot parameter to execInContainer #513

refactor(standalone): add asRoot parameter to execInContainer #513

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