Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
misc/libmasm/module: Fix two use after free in ibmasm_init_one
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.
Details
- Affected product:
- CentOS 6 ELS , CloudLinux 6 ELS , Oracle Linux 6 ELS , Ubuntu 16.04 ELS
- Affected packages:
- linux @ 4.4.0 (+4 more)
In the Linux kernel, the following vulnerability has been resolved:
misc/libmasm/module: Fix two use after free in ibmasm_init_one
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.