synclink fix ldisc buffer argument

Fix call to line discipline receive_buf by synclink drivers.
Dummy flag buffer argument is ignored by N_HDLC line discipline but might
be of insufficient size if accessed by a different line discipline
selected by mistake. flag buffer allocation now matches max size of data
buffer. Unused char_buf buffers are removed.

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/tty/synclinkmp.c b/drivers/tty/synclinkmp.c
index fd43fb6f7cee..33b7314cc6c7 100644
--- a/drivers/tty/synclinkmp.c
+++ b/drivers/tty/synclinkmp.c
@@ -262,8 +262,7 @@ typedef struct _synclinkmp_info {
         bool sca_statctrl_requested;
 
         u32 misc_ctrl_value;
-        char flag_buf[MAX_ASYNC_BUFFER_SIZE];
-        char char_buf[MAX_ASYNC_BUFFER_SIZE];
+        char *flag_buf;
         bool drop_rts_on_tx_done;
 
         struct  _input_signal_events    input_signal_events;
@@ -3553,6 +3552,13 @@ static int alloc_tmp_rx_buf(SLMP_INFO *info)
         info->tmp_rx_buf = kmalloc(info->max_frame_size, GFP_KERNEL);
         if (info->tmp_rx_buf == NULL)
                 return -ENOMEM;
+        /* unused flag buffer to satisfy receive_buf calling interface */
+        info->flag_buf = kzalloc(info->max_frame_size, GFP_KERNEL);
+        if (!info->flag_buf) {
+                kfree(info->tmp_rx_buf);
+                info->tmp_rx_buf = NULL;
+                return -ENOMEM;
+        }
         return 0;
 }
 
@@ -3560,6 +3566,8 @@ static void free_tmp_rx_buf(SLMP_INFO *info)
 {
         kfree(info->tmp_rx_buf);
         info->tmp_rx_buf = NULL;
+        kfree(info->flag_buf);
+        info->flag_buf = NULL;
 }
 
 static int claim_resources(SLMP_INFO *info)