From: Johan Hovold johan@kernel.org

stable inclusion from stable-v4.19.209 commit 9c5b77a7ffc983b2429ce158b50497c5d3c86a69 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4NR CVE: CVE-2021-47403

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit bb8a4fcb2136508224c596a7e665bdba1d7c3c27 upstream.

A reference to the carrier module was taken on every open but was only released once when the final reference to the tty struct was dropped.

Fix this by taking the module reference and initialising the tty driver data when installing the tty.

Fixes: 82a82340bab6 ("ipoctal: get carrier driver to avoid rmmod") Cc: stable@vger.kernel.org # 3.18 Cc: Federico Vaga federico.vaga@cern.ch Acked-by: Samuel Iglesias Gonsalvez siglesias@igalia.com Signed-off-by: Johan Hovold johan@kernel.org Link: https://lore.kernel.org/r/20210917114622.5412-6-johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Liu Shixin liushixin2@huawei.com --- drivers/ipack/devices/ipoctal.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/ipack/devices/ipoctal.c b/drivers/ipack/devices/ipoctal.c index aeadeaafdb26..dc39a84086c7 100644 --- a/drivers/ipack/devices/ipoctal.c +++ b/drivers/ipack/devices/ipoctal.c @@ -86,22 +86,34 @@ static int ipoctal_port_activate(struct tty_port *port, struct tty_struct *tty) return 0; }

-static int ipoctal_open(struct tty_struct *tty, struct file *file) +static int ipoctal_install(struct tty_driver *driver, struct tty_struct *tty) { struct ipoctal_channel *channel = dev_get_drvdata(tty->dev); struct ipoctal *ipoctal = chan_to_ipoctal(channel, tty->index); - int err; - - tty->driver_data = channel; + int res;

if (!ipack_get_carrier(ipoctal->dev)) return -EBUSY;

- err = tty_port_open(&channel->tty_port, tty, file); - if (err) - ipack_put_carrier(ipoctal->dev); + res = tty_standard_install(driver, tty); + if (res) + goto err_put_carrier; + + tty->driver_data = channel; + + return 0; + +err_put_carrier: + ipack_put_carrier(ipoctal->dev); + + return res; +} + +static int ipoctal_open(struct tty_struct *tty, struct file *file) +{ + struct ipoctal_channel *channel = tty->driver_data;

- return err; + return tty_port_open(&channel->tty_port, tty, file); }

static void ipoctal_reset_stats(struct ipoctal_stats *stats) @@ -663,6 +675,7 @@ static void ipoctal_cleanup(struct tty_struct *tty)

static const struct tty_operations ipoctal_fops = { .ioctl = NULL, + .install = ipoctal_install, .open = ipoctal_open, .close = ipoctal_close, .write = ipoctal_write_tty,