Fix the UBSAN: array-index-out-of-bounds issue below by updating counter nvm->nregions before the first access to flexible-array member nvm->regions[].
from kernel bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=220823 Dec 15 22:01:52 orpheus kernel: UBSAN: array-index-out-of-bounds in /var/tmp/portage/sys-kernel/gentoo-kernel-6.18.1/work/linux-6.18/drivers/mtd/devices/mtd_intel_dg.c:750:15 Notice that this flexible array is annotated with the counted_by() attribute, hence the counter must always be updated before the first access to the array. Cc: [email protected] Fixes: ceb5ab3cb646 ("mtd: add driver for intel graphics non-volatile memory device") Reported-by: Randy Dunlap <[email protected]> Closes: https://lore.kernel.org/linux-hardening/[email protected]/ Signed-off-by: Gustavo A. R. Silva <[email protected]> --- drivers/mtd/devices/mtd_intel_dg.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/mtd/devices/mtd_intel_dg.c b/drivers/mtd/devices/mtd_intel_dg.c index 2bab30dcd35f..d3e89fe324b8 100644 --- a/drivers/mtd/devices/mtd_intel_dg.c +++ b/drivers/mtd/devices/mtd_intel_dg.c @@ -768,6 +768,9 @@ static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev, if (!nvm) return -ENOMEM; + /* Update nvm->nregions before first access to nvm->regions[] below. */ + nvm->nregions = nregions; + kref_init(&nvm->refcnt); mutex_init(&nvm->lock); -- 2.43.0
