In the Linux kernel, the following vulnerability has been resolved:
cpufreq: imx6q: fix out-of-bounds write when probed more than once
imx6_soc_volt is allocated fresh on every probe, sized to the number of
ARM OPPs:
imx6_soc_volt = devm_kcalloc(cpu_dev, num, sizeof(*imx6_soc_volt),
GFP_KERNEL);
but it is filled through soc_opp_count, which has static storage and is
never reset. A second bind after an unbind keeps indexing from where the
first one stopped, and writes past the end of the new array.
Unbinding and rebinding the driver on qemu’s mcimx6ul-evk, under KASAN:
BUG: KASAN: slab-out-of-bounds in imx6q_cpufreq_probe+0x3b0/0xa34
Write of size 4 at addr c5e90480 by task binder/73
imx6q_cpufreq_probe from platform_probe+0x88/0xe4
platform_probe from really_probe+0x108/0x384
bind_store from kernfs_fop_write_iter+0x1b4/0x28c
The write lands one u32 past the end of the allocation.
soc_opp_count is only read a few lines below the loop that fills it, so it
never needed static storage. Make it a local.
