CVE-2024-57913

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: f_fs: Remove WARN_ON in functionfs_bind

This commit addresses an issue related to below kernel panic where

panic_on_warn is enabled. It is caused by the unnecessary use of WARN_ON

in functionsfs_bind, which easily leads to the following scenarios.

1.adb_write in adbd 2. UDC write via configfs

================= =====================

->usb_ffs_open_thread() ->UDC write

->open_functionfs() ->configfs_write_iter()

->adb_open() ->gadget_dev_desc_UDC_store()

->adb_write() ->usb_gadget_register_driver_owner

->driver_register()

->StartMonitor() ->bus_add_driver()

->adb_read() ->gadget_bind_driver()

<times-out without BIND event> ->configfs_composite_bind()

->usb_add_function()

->open_functionfs() ->ffs_func_bind()

->adb_open() ->functionfs_bind()

<ffs->state !=FFS_ACTIVE>

The adb_open, adb_read, and adb_write operations are invoked from the

daemon, but trying to bind the function is a process that is invoked by

UDC write through configfs, which opens up the possibility of a race

condition between the two paths. In this race scenario, the kernel panic

occurs due to the WARN_ON from functionfs_bind when panic_on_warn is

enabled. This commit fixes the kernel panic by removing the unnecessary

WARN_ON.

Kernel panic - not syncing: kernel: panic_on_warn set ...

[ 14.542395] Call trace:

[ 14.542464] ffs_func_bind+0x1c8/0x14a8

[ 14.542468] usb_add_function+0xcc/0x1f0

[ 14.542473] configfs_composite_bind+0x468/0x588

[ 14.542478] gadget_bind_driver+0x108/0x27c

[ 14.542483] really_probe+0x190/0x374

[ 14.542488] __driver_probe_device+0xa0/0x12c

[ 14.542492] driver_probe_device+0x3c/0x220

[ 14.542498] __driver_attach+0x11c/0x1fc

[ 14.542502] bus_for_each_dev+0x104/0x160

[ 14.542506] driver_attach+0x24/0x34

[ 14.542510] bus_add_driver+0x154/0x270

[ 14.542514] driver_register+0x68/0x104

[ 14.542518] usb_gadget_register_driver_owner+0x48/0xf4

[ 14.542523] gadget_dev_desc_UDC_store+0xf8/0x144

[ 14.542526] configfs_write_iter+0xf0/0x138