[PATCH 6.9 088/374] ppdev: Add an error check in register_device

Greg Kroah-Hartman
2024-06-06T14:08:56Z

From: Huai-Yuan Liu <qq810974084@gmail.com>

[ Upstream commit fbf740aeb86a4fe82ad158d26d711f2f3be79b3e ]

In register_device, the return value of ida_simple_get is unchecked,
in witch ida_simple_get will use an invalid index value.

To address this issue, index should be checked after ida_simple_get. When
the index value is abnormal, a warning message should be printed, the port
should be dropped, and the value should be recorded.

Fixes: 9a69645dde11 ("ppdev: fix registering same device name")
Signed-off-by: Huai-Yuan Liu <qq810974084@gmail.com>
Link: https://lore.kernel.org/r/20240412083840.234085-1-qq810974084@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/char/ppdev.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index ee951b265213f..58e9dcc2a3087 100644
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -296,28 +296,35 @@ static int register_device(int minor, struct pp_struct *pp)
if (!port) {
pr_warn("%s: no associated port!\n", name);
rc = -ENXIO;
- goto err;
+ goto err_free_name;
}

index = ida_alloc(&ida_index, GFP_KERNEL);
+ if (index < 0) {
+ pr_warn("%s: failed to get index!\n", name);
+ rc = index;
+ goto err_put_port;
+ }
+
memset(&ppdev_cb, 0, sizeof(ppdev_cb));
ppdev_cb.irq_func = pp_irq;
ppdev_cb.flags = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
ppdev_cb.private = pp;
pdev = parport_register_dev_model(port, name, &ppdev_cb, index);
- parport_put_port(port);

if (!pdev) {
pr_warn("%s: failed to register device!\n", name);
rc = -ENXIO;
ida_free(&ida_index, index);
- goto err;
+ goto err_put_port;
}

pp->pdev = pdev;
pp->index = index;
dev_dbg(&pdev->dev, "registered pardevice\n");
-err:
+err_put_port:
+ parport_put_port(port);
+err_free_name:
kfree(name);
return rc;
}
--
2.43.0