--- dropbear-2020.81.orig/svr-authpubkey.c	2020-10-29 14:35:50.000000000 +0100
+++ dropbear-2020.81/svr-authpubkey.c	2020-11-04 03:14:22.641017199 +0100
@@ -386,26 +386,32 @@ static int checkpubkey(const char* keyal
 		goto out;
 	}
 
-	/* we don't need to check pw and pw_dir for validity, since
-	 * its been done in checkpubkeyperms. */
-	len = strlen(ses.authstate.pw_dir);
-	/* allocate max required pathname storage,
-	 * = path + "/.ssh/authorized_keys" + '\0' = pathlen + 22 */
-	filename = m_malloc(len + 22);
-	snprintf(filename, len + 22, "%s/.ssh/authorized_keys", 
-				ses.authstate.pw_dir);
+	/* special case for root authorized_keys in /etc/dropbear/authorized_keys */
+	if (ses.authstate.pw_uid != 0) {
+		/* we don't need to check pw and pw_dir for validity, since
+		 * its been done in checkpubkeyperms. */
+		len = strlen(ses.authstate.pw_dir);
+		/* allocate max required pathname storage,
+		 * = path + "/.ssh/authorized_keys" + '\0' = pathlen + 22 */
+		filename = m_malloc(len + 22);
+		snprintf(filename, len + 22, "%s/.ssh/authorized_keys", 
+					ses.authstate.pw_dir);
 
-#if DROPBEAR_SVR_MULTIUSER
-	/* open the file as the authenticating user. */
-	origuid = getuid();
-	origgid = getgid();
-	if ((setegid(ses.authstate.pw_gid)) < 0 ||
-		(seteuid(ses.authstate.pw_uid)) < 0) {
-		dropbear_exit("Failed to set euid");
-	}
-#endif
+		/* open the file as the authenticating user. */
+		origuid = getuid();
+		origgid = getgid();
+		if ((setegid(ses.authstate.pw_gid)) < 0 ||
+			(seteuid(ses.authstate.pw_uid)) < 0) {
+			dropbear_exit("Failed to set euid");
+		}
 
-	authfile = fopen(filename, "r");
+		authfile = fopen(filename, "r");
+
+	} else {
+		origuid = getuid();
+		origgid = getgid();
+		authfile = fopen("/etc/dropbear/authorized_keys","r");
+	}
 
 #if DROPBEAR_SVR_MULTIUSER
 	if ((seteuid(origuid)) < 0 ||
@@ -474,27 +480,37 @@ static int checkpubkeyperms() {
 		goto out;
 	}
 
-	/* allocate max required pathname storage,
-	 * = path + "/.ssh/authorized_keys" + '\0' = pathlen + 22 */
-	len += 22;
-	filename = m_malloc(len);
-	strlcpy(filename, ses.authstate.pw_dir, len);
+	if (ses.authstate.pw_uid != 0) {
+		/* allocate max required pathname storage,
+		 * = path + "/.ssh/authorized_keys" + '\0' = pathlen + 22 */
+		filename = m_malloc(len + 22);
+		strncpy(filename, ses.authstate.pw_dir, len+1);
+ 
+		/* check ~ */
+		if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
+			goto out;
+		}
 
-	/* check ~ */
-	if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
-		goto out;
-	}
+		/* check ~/.ssh */
+		strncat(filename, "/.ssh", 5); /* strlen("/.ssh") == 5 */
+		if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
+			goto out;
+		}
 
-	/* check ~/.ssh */
-	strlcat(filename, "/.ssh", len);
-	if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
-		goto out;
-	}
+		/* now check ~/.ssh/authorized_keys */
+		strncat(filename, "/authorized_keys", 16);
+		if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
+			goto out;
+		}
 
-	/* now check ~/.ssh/authorized_keys */
-	strlcat(filename, "/authorized_keys", len);
-	if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
-		goto out;
+	} else {
+
+		if (checkfileperm("/etc/dropbear") != DROPBEAR_SUCCESS) {
+			goto out;
+		}
+		if (checkfileperm("/etc/dropbear/authorized_keys") != DROPBEAR_SUCCESS) {
+			goto out;
+		}
 	}
 
 	/* file looks ok, return success */