autoboot: fix illegal memory access when stop key and delay key are empty

If both stop key and delay key are empty, the length of these
keys is 0. The subtraction operation will cause the u_int type
variable to overflow, will cause illegal memory access in key
input loop.

This commit fixes this bug by using int type instead of u_init.
Acked-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

diff --git a/common/autoboot.c b/common/autoboot.c
index ddb6246be347e9e732504eb849990c52577b86cb..b025fd99a0bf6fbc9d3c70b34b7898aef04878df 100644 (file)
--- a/common/autoboot.c
+++ b/common/autoboot.c
@@ -164,9 +164,9 @@ static int passwd_abort_key(uint64_t etime)
        };
 
        char presskey[MAX_DELAY_STOP_STR];
-       u_int presskey_len = 0;
-       u_int presskey_max = 0;
-       u_int i;
+       int presskey_len = 0;
+       int presskey_max = 0;
+       int i;
 
 #  ifdef CONFIG_AUTOBOOT_DELAY_STR
        if (delaykey[0].str == NULL)