kgdbts: Read buffer overflow

Prevent write to put_buf[BUFMAX] in kgdb test suite.

If put_buf_cnt was BUFMAX - 1 at the earlier test,
`\0' is written to put_buf[BUFMAX].

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c
index e4ff50b95a5e..2ab04923d70f 100644
--- a/drivers/misc/kgdbts.c
+++ b/drivers/misc/kgdbts.c
@@ -712,6 +712,12 @@ static int run_simple_test(int is_get_char, int chr)
 
         /* End of packet == #XX so look for the '#' */
         if (put_buf_cnt > 3 && put_buf[put_buf_cnt - 3] == '#') {
+                if (put_buf_cnt >= BUFMAX) {
+                        eprintk("kgdbts: ERROR: put buffer overflow on"
+                                " '%s' line %i\n", ts.name, ts.idx);
+                        put_buf_cnt = 0;
+                        return 0;
+                }
                 put_buf[put_buf_cnt] = '\0';
                 v2printk("put%i: %s\n", ts.idx, put_buf);
                 /* Trigger check here */