]> git.ipfire.org Git - thirdparty/kernel/linux.git/commit
mtd: jedec_probe: fix shift-out-of-bounds UB in JEDEC ID masking
authorChenxi Hou <ch395@njit.edu>
Thu, 22 Jan 2026 01:32:50 +0000 (20:32 -0500)
committerMiquel Raynal <miquel.raynal@bootlin.com>
Thu, 22 Jan 2026 14:07:39 +0000 (15:07 +0100)
commit2b14660c1caf0b67adf99428a225f71ed653437d
tree2df54724fb023d52e9acb731b5369f688f94543b
parent779c59274d03cc5c07237a2c845dfb71cff77705
mtd: jedec_probe: fix shift-out-of-bounds UB in JEDEC ID masking

UBSAN reports shift-out-of-bounds in jedec_read_mfr() and jedec_read_id():

  UBSAN: shift-out-of-bounds in drivers/mtd/chips/jedec_probe.c:1924:13
  shift exponent 32 is too large for 32-bit type 'int'
  UBSAN: shift-out-of-bounds in drivers/mtd/chips/jedec_probe.c:1940:12
  shift exponent 32 is too large for 32-bit type 'int'

The JEDEC manufacturer/device ID masking uses:

  (1 << (cfi->device_type * 8)) - 1

When cfi->device_type is 4, this evaluates to 1 << 32. Since the
literal '1' has type int, this is a 32-bit shift and is undefined behavior.

Fix it by using a 64-bit literal (1ULL) so the shift is performed in a 64-bit type.

Co-developed-by: Hui Peng <benquike@gmail.com>
Signed-off-by: Hui Peng <benquike@gmail.com>
Co-developed-by: Zhihao Yao (Zephyr) <zhihao.yao@njit.edu>
Signed-off-by: Zhihao Yao (Zephyr) <zhihao.yao@njit.edu>
Signed-off-by: Chenxi Hou <ch395@njit.edu>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
drivers/mtd/chips/jedec_probe.c