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>

4 files changed, 47 insertions, 8 deletions

diff --git a/drivers/char/pcmcia/synclink_cs.c b/drivers/char/pcmcia/synclink_cs.c
index b66eaa04f8cb..b2f35d786025 100644
--- a/drivers/char/pcmcia/synclink_cs.c
+++ b/drivers/char/pcmcia/synclink_cs.c
@@ -210,7 +210,7 @@ typedef struct _mgslpc_info {
         char testing_irq;
         unsigned int init_error;        /* startup error (DIAGS)        */
 
-        char flag_buf[MAX_ASYNC_BUFFER_SIZE];
+        char *flag_buf;
         bool drop_rts_on_tx_done;
 
         struct  _input_signal_events    input_signal_events;
@@ -2674,6 +2674,14 @@ static int rx_alloc_buffers(MGSLPC_INFO *info)
         if (info->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->rx_buf);
+                info->rx_buf = NULL;
+                return -ENOMEM;
+        }
+        
         rx_reset_buffers(info);
         return 0;
 }
@@ -2682,6 +2690,8 @@ static void rx_free_buffers(MGSLPC_INFO *info)
 {
         kfree(info->rx_buf);
         info->rx_buf = NULL;
+        kfree(info->flag_buf);
+        info->flag_buf = NULL;
 }
 
 static int claim_resources(MGSLPC_INFO *info)
diff --git a/drivers/tty/synclink.c b/drivers/tty/synclink.c
index 9e071f6985f6..d42b66195a49 100644
--- a/drivers/tty/synclink.c
+++ b/drivers/tty/synclink.c
@@ -291,8 +291,7 @@ struct mgsl_struct {
         bool lcr_mem_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;
 
         bool loopmode_insert_requested;
@@ -3898,7 +3897,13 @@ static int mgsl_alloc_intermediate_rxbuffer_memory(struct mgsl_struct *info)
         info->intermediate_rxbuffer = kmalloc(info->max_frame_size, GFP_KERNEL | GFP_DMA);
         if ( info->intermediate_rxbuffer == 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->intermediate_rxbuffer);
+                info->intermediate_rxbuffer = NULL;
+                return -ENOMEM;
+        }
         return 0;
 
 }       /* end of mgsl_alloc_intermediate_rxbuffer_memory() */
@@ -3917,6 +3922,8 @@ static void mgsl_free_intermediate_rxbuffer_memory(struct mgsl_struct *info)
 {
         kfree(info->intermediate_rxbuffer);
         info->intermediate_rxbuffer = NULL;
+        kfree(info->flag_buf);
+        info->flag_buf = NULL;
 
 }       /* end of mgsl_free_intermediate_rxbuffer_memory() */
 
diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index aba1e59f4a88..62a0db7ead07 100644
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -317,8 +317,7 @@ struct slgt_info {
         unsigned char *tx_buf;
         int tx_count;
 
-        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;
 
@@ -3355,11 +3354,24 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
         return retval;
 }
 
+/*
+ * allocate buffers used for calling line discipline receive_buf
+ * directly in synchronous mode
+ * note: add 5 bytes to max frame size to allow appending
+ * 32-bit CRC and status byte when configured to do so
+ */
 static int alloc_tmp_rbuf(struct slgt_info *info)
 {
         info->tmp_rbuf = kmalloc(info->max_frame_size + 5, GFP_KERNEL);
         if (info->tmp_rbuf == NULL)
                 return -ENOMEM;
+        /* unused flag buffer to satisfy receive_buf calling interface */
+        info->flag_buf = kzalloc(info->max_frame_size + 5, GFP_KERNEL);
+        if (!info->flag_buf) {
+                kfree(info->tmp_rbuf);
+                info->tmp_rbuf = NULL;
+                return -ENOMEM;
+        }
         return 0;
 }
 
@@ -3367,6 +3379,8 @@ static void free_tmp_rbuf(struct slgt_info *info)
 {
         kfree(info->tmp_rbuf);
         info->tmp_rbuf = NULL;
+        kfree(info->flag_buf);
+        info->flag_buf = NULL;
 }
 
 /*
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)