[PATCH 5.4 012/149] misc/libmasm/module: Fix two use after free in ibmasm_init_one

Greg Kroah-Hartman
2021-07-19T16:42:32Z

From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>

[ Upstream commit 7272b591c4cb9327c43443f67b8fbae7657dd9ae ]

In ibmasm_init_one, it calls ibmasm_init_remote_input_dev().
Inside ibmasm_init_remote_input_dev, mouse_dev and keybd_dev are
allocated by input_allocate_device(), and assigned to
sp->remote.mouse_dev and sp->remote.keybd_dev respectively.

In the err_free_devices error branch of ibmasm_init_one,
mouse_dev and keybd_dev are freed by input_free_device(), and return
error. Then the execution runs into error_send_message error branch
of ibmasm_init_one, where ibmasm_free_remote_input_dev(sp) is called
to unregister the freed sp->remote.mouse_dev and sp->remote.keybd_dev.

My patch add a "error_init_remote" label to handle the error of
ibmasm_init_remote_input_dev(), to avoid the uaf bugs.

Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Link: https://lore.kernel.org/r/20210426170620.10546-1-lyl2019@mail.ustc.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/misc/ibmasm/module.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/ibmasm/module.c b/drivers/misc/ibmasm/module.c
index 4edad6c445d3..dc8a06c06c63 100644
--- a/drivers/misc/ibmasm/module.c
+++ b/drivers/misc/ibmasm/module.c
@@ -111,7 +111,7 @@ static int ibmasm_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
result = ibmasm_init_remote_input_dev(sp);
if (result) {
dev_err(sp->dev, "Failed to initialize remote queue\n");
- goto error_send_message;
+ goto error_init_remote;
}

result = ibmasm_send_driver_vpd(sp);
@@ -131,8 +131,9 @@ static int ibmasm_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
return 0;

error_send_message:
- disable_sp_interrupts(sp->base_address);
ibmasm_free_remote_input_dev(sp);
+error_init_remote:
+ disable_sp_interrupts(sp->base_address);
free_irq(sp->irq, (void *)sp);
error_request_irq:
iounmap(sp->base_address);
--
2.30.2