If fwtty_install() will be invoked with such tty->index that will be
not less than MAX_TOTAL_PORTS then fwtty_port_get() will return NULL and
fwtty_install() will either assign it to tty->driver_data or dereference
in fwtty_port_put() (if tty_standard_install() will fail). The similar
situation is with fwloop_install(). The patch fixes both cases.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Evgeny Novikov <[email protected]>
---
drivers/staging/fwserial/fwserial.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/staging/fwserial/fwserial.c b/drivers/staging/fwserial/fwserial.c
index 1ee6382cafc4..d0810896511e 100644
--- a/drivers/staging/fwserial/fwserial.c
+++ b/drivers/staging/fwserial/fwserial.c
@@ -1069,6 +1069,9 @@ static int fwtty_install(struct tty_driver *driver, struct tty_struct *tty)
struct fwtty_port *port = fwtty_port_get(tty->index);
int err;
+ if (!port)
+ return -ENODEV;
+
err = tty_standard_install(driver, tty);
if (!err)
tty->driver_data = port;
@@ -1082,6 +1085,9 @@ static int fwloop_install(struct tty_driver *driver, struct tty_struct *tty)
struct fwtty_port *port = fwtty_port_get(table_idx(tty->index));
int err;
+ if (!port)
+ return -ENODEV;
+
err = tty_standard_install(driver, tty);
if (!err)
tty->driver_data = port;
--
2.26.2
On Wed, May 26, 2021 at 11:21:36AM +0300, Evgeny Novikov wrote:
> Now I see that we need to restrict in specifications those values that
> can be passed to the install callback of tty_operations according to
> a first actual argument of tty_alloc_driver(). Thank you for pointing
> this out.
I do not understand what you mean here at all, sorry.
What "specifications"?
confused,
greg k-h