From 167b7a41ff171c2593a019eaba84ac5317f3c499 Mon Sep 17 00:00:00 2001
From: Warner Losh <imp@FreeBSD.org>
Date: Fri, 5 Jan 2018 07:09:24 +0000
Subject: [PATCH] Set dp to NULL when we free it, and tree a NULL dp as an
 error condition. This should prevent a double free. In addition, prevent a
 leak by freeing dp each loop and when we're done.

CID: 1383577
Sponsored by: Netflix
---
 lib/libefivar/efivar-dp-xlate.c | 1 +
 usr.sbin/efidp/efidp.c          | 6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/libefivar/efivar-dp-xlate.c b/lib/libefivar/efivar-dp-xlate.c
index 58c89068645a..5c9398d9f43f 100644
--- a/lib/libefivar/efivar-dp-xlate.c
+++ b/lib/libefivar/efivar-dp-xlate.c
@@ -663,6 +663,7 @@ path_to_dp(struct gmesh *mesh, char *path, efidp *dp)
 	free(rp);
 	if (rv != 0) {
 		free(*dp);
+		*dp = NULL;
 	}
 	return (rv);
 }
diff --git a/usr.sbin/efidp/efidp.c b/usr.sbin/efidp/efidp.c
index a4db95abeeac..e12491ecabf5 100644
--- a/usr.sbin/efidp/efidp.c
+++ b/usr.sbin/efidp/efidp.c
@@ -143,10 +143,13 @@ unix_to_efi(void)
 	char *walker;
 	int rv;
 
+	dp = NULL;
 	while (fgets(buffer, sizeof(buffer), stdin)) {
 		walker= trim(buffer);
+		free(dp);
+		dp = NULL;
 		rv = efivar_unix_path_to_device_path(walker, &dp);
-		if (rv != 0) {
+		if (rv != 0 || dp == NULL) {
 			errno = rv;
 			warn("Can't convert '%s' to efi", walker);
 			continue;
@@ -158,6 +161,7 @@ unix_to_efi(void)
 		}
 		printf("%s\n", efi);
 	}
+	free(dp);
 }
 
 static void