From 34a34e72334d7613b7a17e02a2f51a65a883dd02 Mon Sep 17 00:00:00 2001
From: Michael Smithhisler <michael.smithhisler@hashicorp.com>
Date: Wed, 8 Jan 2025 08:50:33 -0500
Subject: [PATCH] plugins: validate logmon process during reattach (#24798)

---
 .changelog/24798.txt    |  3 +++
 client/logmon/plugin.go | 10 ++++++++++
 2 files changed, 13 insertions(+)
 create mode 100644 .changelog/24798.txt

diff --git a/.changelog/24798.txt b/.changelog/24798.txt
new file mode 100644
index 00000000000..902a2a6d7f5
--- /dev/null
+++ b/.changelog/24798.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+drivers: validate logmon plugin during reattach
+```
diff --git a/client/logmon/plugin.go b/client/logmon/plugin.go
index d79be2b1bbd..d77b88e50ba 100644
--- a/client/logmon/plugin.go
+++ b/client/logmon/plugin.go
@@ -59,6 +59,16 @@ func LaunchLogMon(logger hclog.Logger, reattachConfig *plugin.ReattachConfig) (L
 		return nil, nil, err
 	}
 
+	// Note: Similar to reattaching to executors, Go-plugin uses localhost
+	// ports on Windows. On reattach, it may attach to another process
+	// listening on that port. We should validate it is actually a plugin.
+	if conf.Reattach != nil {
+		if err := rpcClient.Ping(); err != nil {
+			logger.Warn("failed to ping plugin process during reattach", "error", err)
+			return nil, nil, err
+		}
+	}
+
 	l := raw.(LogMon)
 	return l, client, nil
 }