CVE-2026-80575: Input: cs40l50-vibra - validate custom data from user space

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

Input: cs40l50-vibra - validate custom data from user space

cs40l50add() copies the custom data of an FFPERIODIC/FFCUSTOM effect straight from the ffeffect the user passed to EVIOCSFF, without requiring it to hold anything:

workdata.customdata = memduparrayuser(periodic->customdata, periodic->customlen, sizeof(s16)); workdata.customlen = periodic->customlen;

The driver then reads two words out of that buffer: customdata[0] as the waveform bank in cs40l50effectbankset(), and customdata[1] as the index within the bank in cs40l50effectindexset(). Neither read is covered by a length check, and customlen is fully user controlled:

- customlen == 0 makes memduparrayuser() call memdupuser() with a length of zero, which returns ZEROSIZEPTR rather than an error, so customdata[0] dereferences it.

- customlen == 1 allocates two bytes. A bank of ROM or RAM keeps effect->type out of the OWT case, and customdata[1] is then read one word past the allocation.

The bank value itself is also mishandled. It is masked with CS40L50CUSTOMDATAMASK (0xffff) but stored in an s16, so a customdata[0] of 0x8000 or above wraps to a negative value that passes the "banktype >= CS40L50WVFRMBANKNUM" test. cs40l50effectindexset() indexes vib->dsp.banks[] with it before the switch statement's default case gets a chance to reject it:

baseindex = vib->dsp.banks[effect->type].baseindex; maxindex = vib->dsp.banks[effect->type].maxindex;

Require the two words the driver reads to be present, and hold the masked bank in a u32 so the existing upper-bound test covers the whole range. The da7280 haptic driver already range checks customlen this way.