hda_generic_machine_select() appends -idisp to the tplg filename by
allocating a new string with devm_kasprintf(), then stores the string
right back into the global variable snd_soc_acpi_intel_hda_machines.
When the module is unloaded, this memory is freed, resulting in a global
variable pointing to freed memory. Reloading the module then triggers
a use-after-free:
BUG: KFENCE: use-after-free read in string+0x48/0xe0
Use-after-free read at 0x00000000967e0109 (in kfence-#99):
string+0x48/0xe0
vsnprintf+0x329/0x6e0
devm_kvasprintf+0x54/0xb0
devm_kasprintf+0x58/0x80
hda_machine_select.cold+0x198/0x17a2 [snd_sof_intel_hda_generic]
sof_probe_work+0x7f/0x600 [snd_sof]
process_one_work+0x17b/0x330
worker_thread+0x2ce/0x3f0
kthread+0xcf/0x100
ret_from_fork+0x31/0x50
ret_from_fork_asm+0x1a/0x30
kfence-#99: 0x00000000198a940f-0x00000000ace47d9d, size=64, cache=kmalloc-64
allocated by task 333 on cpu 8 at 17.798069s (130.453553s ago):
devm_kmalloc+0x52/0x120
devm_kvasprintf+0x66/0xb0
devm_kasprintf+0x58/0x80
hda_machine_select.cold+0x198/0x17a2 [snd_sof_intel_hda_generic]
sof_probe_work+0x7f/0x600 [snd_sof]
process_one_work+0x17b/0x330
worker_thread+0x2ce/0x3f0
kthread+0xcf/0x100
ret_from_fork+0x31/0x50
ret_from_fork_asm+0x1a/0x30
freed by task 1543 on cpu 4 at 141.586686s (6.665010s ago):
release_nodes+0x43/0xb0
devres_release_all+0x90/0xf0
device_unbind_cleanup+0xe/0x70
device_release_driver_internal+0x1c1/0x200
driver_detach+0x48/0x90
bus_remove_driver+0x6d/0xf0
pci_unregister_driver+0x42/0xb0
__do_sys_delete_module+0x1d1/0x310
do_syscall_64+0x82/0x190
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fix it by copying the match array with devm_kmemdup_array() before we
modify it.
Fixes: 5458411d75 ("ASoC: SOF: Intel: hda: refactoring topology name fixup for HDA mach")
Suggested-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Signed-off-by: Tavian Barnes <tavianator@tavianator.com>
Link: https://patch.msgid.link/570b15570b274520a0d9052f4e0f064a29c950ef.1747229716.git.tavianator@tavianator.com
Signed-off-by: Mark Brown <broonie@kernel.org>
7dd7f39fce