Messages in this thread Patch in this message | | | From | Andrea Righi <> | Subject | [PATCH] mtd: spi-nor: fix shift-out-of-bounds in spi_nor_set_erase_type() | Date | Tue, 21 Feb 2023 12:13:46 +0100 |
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It seems that according to JEDEC JESD216B Standard erase size needs to be a power of 2, but sometimes we set the size to 0 (e.g., in spi_nor_parse_4bait()) causing UBSAN warnings like the following:
UBSAN: shift-out-of-bounds in drivers/mtd/spi-nor/core.c:2026:24 shift exponent 4294967295 is too large for 32-bit type 'int' Hardware name: Dell Inc. XPS 13 9300/077Y9N, BIOS 1.11.0 03/22/2022 Call Trace: <TASK> show_stack+0x4e/0x61 dump_stack_lvl+0x4a/0x6f dump_stack+0x10/0x18 ubsan_epilogue+0x9/0x3a __ubsan_handle_shift_out_of_bounds.cold+0x61/0xef spi_nor_set_erase_type.cold+0x16/0x1e [spi_nor] spi_nor_parse_4bait+0x270/0x380 [spi_nor] spi_nor_parse_sfdp+0x47f/0x610 [spi_nor]
Fix by checking if size is a power when setting struct spi_nor_erase_type, otherwise consider size, mask and shift as invalid.
Fixes: 5390a8df769e ("mtd: spi-nor: add support to non-uniform SFDP SPI NOR flash memories") Reported-by: Emil Renner Berthing <emil.renner.berthing@canonical.com> Signed-off-by: Andrea Righi <andrea.righi@canonical.com> --- drivers/mtd/spi-nor/core.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c index d67c926bca8b..3c5b5bf9cbd1 100644 --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -2019,11 +2019,17 @@ spi_nor_spimem_adjust_hwcaps(struct spi_nor *nor, u32 *hwcaps) void spi_nor_set_erase_type(struct spi_nor_erase_type *erase, u32 size, u8 opcode) { - erase->size = size; erase->opcode = opcode; /* JEDEC JESD216B Standard imposes erase sizes to be power of 2. */ - erase->size_shift = ffs(erase->size) - 1; - erase->size_mask = (1 << erase->size_shift) - 1; + if (likely(is_power_of_2(size))) { + erase->size = size; + erase->size_shift = ffs(erase->size) - 1; + erase->size_mask = (1 << erase->size_shift) - 1; + } else { + erase->size = 0u; + erase->size_shift = ~0u; + erase->size_mask = ~0u; + } } /** -- 2.38.1
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