[PATCH] drivers/tty: Use get_user instead of dereferencing user pointer

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

We should use the get_user macro instead of dereferencing user
pointers directly.

This patch fixes the following sparse warning:
drivers/tty/n_tty.c:1648:51: warning:
	dereference of noderef expression

Signed-off-by: Emil Goode <emilgoode@xxxxxxxxx>
I'm a newbie so please review carefully.
Not sure if I should add error handling for the get_user call here.

 drivers/tty/n_tty.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 94b6eda..5ff63cc 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1630,6 +1630,7 @@ static int copy_from_read_buf(struct tty_struct *tty,
 	int retval;
 	size_t n;
 	unsigned long flags;
+	unsigned char ch;
 	retval = 0;
 	spin_lock_irqsave(&tty->read_lock, flags);
@@ -1645,7 +1646,8 @@ static int copy_from_read_buf(struct tty_struct *tty,
 		tty->read_cnt -= n;
 		/* Turn single EOF into zero-length read */
 		if (L_EXTPROC(tty) && tty->icanon && n == 1) {
-			if (!tty->read_cnt && (*b)[n-1] == EOF_CHAR(tty))
+			get_user(ch, b[n-1]);
+			if (!tty->read_cnt && ch == EOF_CHAR(tty))
 		spin_unlock_irqrestore(&tty->read_lock, flags);

To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Linux Netdev]     [Kernel Newbies]     [Share Photos]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Photo]     [Yosemite]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]     [Free Dating]

Add to Google Powered by Linux