From 6b5599bb1238bb923aeaa854aaa393f09173aa1d Mon Sep 17 00:00:00 2001
From: Ivan Grokhotkov <ivan@espressif.com>
Date: Tue, 3 May 2022 21:26:14 +0200
Subject: [PATCH] console: linenoiseProbe: check if response is valid

Previously linenoiseProbe would accept any 4 byte response, even one
that isn't expected. This adds a check that the first byte of the
response is ESC.
Suggested in https://github.com/espressif/esp-idf/issues/8839.
---
 components/console/linenoise/linenoise.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/components/console/linenoise/linenoise.c b/components/console/linenoise/linenoise.c
index f074d67c99..4fec09c33a 100644
--- a/components/console/linenoise/linenoise.c
+++ b/components/console/linenoise/linenoise.c
@@ -1057,6 +1057,10 @@ int linenoiseProbe(void) {
         if (cb < 0) {
             continue;
         }
+        if (read_bytes == 0 && c != '\x1b') {
+            /* invalid response */
+            break;
+        }
         read_bytes += cb;
     }
     /* Restore old mode */