From c8b7ca2ba2ef9a57103b5c05e6e29b54b0c6fa48 Mon Sep 17 00:00:00 2001
From: Valentin Rothberg <rothberg@redhat.com>
Date: Fri, 29 Oct 2021 10:28:38 +0200
Subject: pod/container create: resolve conflicts of generated names

Address the TOCTOU when generating random names by having at most 10
attempts to assign a random name when creating a pod or container.

[NO TESTS NEEDED] since I do not know a way to force a conflict with
randomly generated names in a reasonable time frame.

Fixes: #11735
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
---
 libpod/runtime_pod_linux.go | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

(limited to 'libpod/runtime_pod_linux.go')

diff --git a/libpod/runtime_pod_linux.go b/libpod/runtime_pod_linux.go
index 3a6098de8..de00eb8e0 100644
--- a/libpod/runtime_pod_linux.go
+++ b/libpod/runtime_pod_linux.go
@@ -43,18 +43,6 @@ func (r *Runtime) NewPod(ctx context.Context, p specgen.PodSpecGenerator, option
 		}
 	}
 
-	if pod.config.Name == "" {
-		name, err := r.generateName()
-		if err != nil {
-			return nil, err
-		}
-		pod.config.Name = name
-	}
-
-	if p.InfraContainerSpec != nil && p.InfraContainerSpec.Hostname == "" {
-		p.InfraContainerSpec.Hostname = pod.config.Name
-	}
-
 	// Allocate a lock for the pod
 	lock, err := r.lockManager.AllocateLock()
 	if err != nil {
@@ -131,9 +119,33 @@ func (r *Runtime) NewPod(ctx context.Context, p specgen.PodSpecGenerator, option
 		logrus.Infof("Pod has an infra container, but shares no namespaces")
 	}
 
-	if err := r.state.AddPod(pod); err != nil {
-		return nil, errors.Wrapf(err, "error adding pod to state")
+	// Unless the user has specified a name, use a randomly generated one.
+	// Note that name conflicts may occur (see #11735), so we need to loop.
+	generateName := pod.config.Name == ""
+	var addPodErr error
+	for {
+		if generateName {
+			name, err := r.generateName()
+			if err != nil {
+				return nil, err
+			}
+			pod.config.Name = name
+		}
+
+		if p.InfraContainerSpec != nil && p.InfraContainerSpec.Hostname == "" {
+			p.InfraContainerSpec.Hostname = pod.config.Name
+		}
+		if addPodErr = r.state.AddPod(pod); addPodErr == nil {
+			return pod, nil
+		}
+		if !generateName || (errors.Cause(addPodErr) != define.ErrPodExists && errors.Cause(addPodErr) != define.ErrCtrExists) {
+			break
+		}
+	}
+	if addPodErr != nil {
+		return nil, errors.Wrapf(addPodErr, "error adding pod to state")
 	}
+
 	return pod, nil
 }
 
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