Hello,

this patch prevents getty(8) from sending empty login names to login(1).

To reproduce the bug, type some characters, erase the entire line and press
enter/return.

---
 libexec/getty/main.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/libexec/getty/main.c b/libexec/getty/main.c
index 74b3aa27779..5726d5d6838 100644
--- a/libexec/getty/main.c
+++ b/libexec/getty/main.c
@@ -59,7 +59,7 @@
 
 struct termios tmode, omode;
 
-int crmod, digit, lower, upper;
+int crmod, lower;
 
 char	hostname[HOST_NAME_MAX+1];
 char	globalhostname[HOST_NAME_MAX+1];
@@ -318,7 +318,10 @@ main(int argc, char *argv[])
 				xputs("user names may not start with '-'.");
 				continue;
 			}
-			if (!(upper || lower || digit))
+			for (i = 0; name[i]; i++)
+				if (isalnum(name[i]))
+					break;
+			if (name[i] == '\0')
 				continue;
 			setflags(2);
 			if (crmod) {
@@ -381,7 +384,7 @@ getname(void)
 		syslog(LOG_ERR, "%s: %m", ttyn);
 		exit(1);
 	}
-	crmod = digit = lower = upper = 0;
+	crmod = lower = 0;
 	np = name;
 	for (;;) {
 		oflush();
@@ -409,8 +412,6 @@ getname(void)
 		}
 		if (islower(c))
 			lower = 1;
-		else if (isupper(c))
-			upper = 1;
 		else if (c == ERASE || c == '\b') {
 			if (np > name) {
 				if (*--np == '\033')
@@ -432,8 +433,7 @@ getname(void)
 			prompt();
 			np = name;
 			continue;
-		} else if (isdigit(c))
-			digit++;
+		}
 		if (IG && (c <= ' ' || c > 0176))
 			continue;
 		*np++ = c;
-- 
2.53.0