[v2][PATCH] regulator: pfuze100: Fix the global-out-of-bounds access in pfuze100_regulator_probe()

[Xiaolei Wang]

The pfuze_chip::regulator_descs is an array of size
PFUZE100_MAX_REGULATOR, the pfuze_chip::pfuze_regulators
is the pointer to the real regulators of a specific device.
The number of real regulator is supposed to be less than
the PFUZE100_MAX_REGULATOR, so we should use the size of
'regulator_num * sizeof(struct pfuze_regulator)' in memcpy().
This fixes the out of bounds access bug reported by KASAN.
  BUG: KASAN: global-out-of-bounds in pfuze100_regulator_probe+0x380/0x8b8
  Read of size 3968 at addr c3390640 by task swapper/0/1

  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.0.0-rc1-yocto-standard+ #2
  Hardware name: Freescale i.MX6 SoloX (Device Tree)
   unwind_backtrace from show_stack+0x18/0x1c
   show_stack from dump_stack_lvl+0x68/0x90
   dump_stack_lvl from print_report+0x58/0x4c8
   print_report from kasan_report+0x7c/0x98
   kasan_report from kasan_check_range+0x20/0x170
   kasan_check_range from memcpy+0x28/0x68
   memcpy from pfuze100_regulator_probe+0x380/0x8b8
   pfuze100_regulator_probe from i2c_device_probe+0x37c/0x39c
   i2c_device_probe from really_probe+0x1cc/0x398
   really_probe from __driver_probe_device+0x118/0x124
   __driver_probe_device from driver_probe_device+0x5c/0xf0
   driver_probe_device from __driver_attach+0x144/0x160
   __driver_attach from bus_for_each_dev+0xf4/0x12c
   bus_for_each_dev from bus_add_driver+0x124/0x264
   bus_add_driver from driver_register+0x130/0x188
   driver_register from i2c_register_driver+0x80/0xa8
   i2c_register_driver from do_one_initcall+0x180/0x39c
   do_one_initcall from kernel_init_freeable+0x374/0x3cc
   kernel_init_freeable from kernel_init+0x1c/0x150
   kernel_init from ret_from_fork+0x14/0x2c

Signed-off-by: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
---
 drivers/regulator/pfuze100-regulator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/regulator/pfuze100-regulator.c b/drivers/regulator/pfuze100-regulator.c
index 6b617024a67d..d899d6e98fb8 100644
--- a/drivers/regulator/pfuze100-regulator.c
+++ b/drivers/regulator/pfuze100-regulator.c
@@ -766,7 +766,7 @@ static int pfuze100_regulator_probe(struct i2c_client *client,
 		((pfuze_chip->chip_id == PFUZE3000) ? "3000" : "3001"))));
 
 	memcpy(pfuze_chip->regulator_descs, pfuze_chip->pfuze_regulators,
-		sizeof(pfuze_chip->regulator_descs));
+		regulator_num * sizeof(struct pfuze_regulator));
 
 	ret = pfuze_parse_regulators_dt(pfuze_chip);
 	if (ret)
-- 
2.25.1