> different runs). Looking at code, the following looks suspicious -- we
> limit copy by 512 bytes, but use the original count which can be
> larger than 512:
>
> static void sixpack_receive_buf(struct tty_struct *tty,
> const unsigned char *cp, char *fp, int count)
> {
> unsigned char buf[512];
> ....
> memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf));
> ....
> sixpack_decode(sp, buf, count1);
>
>
> On commit 0f98f121e1670eaa2a2fbb675e07d6ba7f0e146f of linux-next.
With the sane tty locking we now have I believe the following is safe as
we consume the bytes and move them into the decoded buffer before
returning.
diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
index 5a1e985..470b3dc 100644
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -127,7 +127,7 @@ struct sixpack {
#define AX25_6PACK_HEADER_LEN 0
-static void sixpack_decode(struct sixpack *, unsigned char[], int);
+static void sixpack_decode(struct sixpack *, const unsigned char[], int);
static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char);
/*
@@ -428,7 +428,7 @@ out:
/*
* Handle the 'receiver data ready' interrupt.
- * This function is called by the 'tty_io' module in the kernel when
+ * This function is called by the tty module in the kernel when
* a block of 6pack data has been received, which can now be decapsulated
* and sent on to some IP layer for further processing.
*/
@@ -436,7 +436,6 @@ static void sixpack_receive_buf(struct tty_struct *tty,
const unsigned char *cp, char *fp, int count)
{
struct sixpack *sp;
- unsigned char buf[512];
int count1;
if (!count)
@@ -446,10 +445,7 @@ static void sixpack_receive_buf(struct tty_struct *tty,
if (!sp)
return;
- memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf));
-
/* Read the characters out of the buffer */
-
count1 = count;
while (count) {
count--;
@@ -459,7 +455,7 @@ static void sixpack_receive_buf(struct tty_struct *tty,
continue;
}
}
- sixpack_decode(sp, buf, count1);
+ sixpack_decode(sp, cp, count1);
sp_put(sp);
tty_unthrottle(tty);
@@ -992,7 +988,7 @@ static void decode_std_command(struct sixpack *sp, unsigned char cmd)
/* decode a 6pack packet */
static void
-sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count)
+sixpack_decode(struct sixpack *sp, const unsigned char *pre_rbuff, int count)
{
unsigned char inbyte;
int count1;