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Message-ID: <b8d01f36-663a-928a-6dbe-64952b5bd8d0@microchip.com>
Date: Wed, 16 Mar 2022 07:47:40 +0000
From: <Tudor.Ambarus@...rochip.com>
To: <Alexander.Stein@...group.com>, <linux-mtd@...ts.infradead.org>
CC: <michael@...le.cc>, <p.yadav@...com>, <vigneshr@...com>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] mtd: spi-nor: Fix shift-out-of-bounds
On 3/16/22 09:39, Alexander Stein wrote:
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>
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> Hello,
hi,
>
> Am Samstag, 6. November 2021, 08:56:15 CET schrieb Tudor Ambarus:
>> When paring SFDP we may choose to mask out an erase type, passing
>> an erase size of zero to spi_nor_set_erase_type().
>> Fix shift-out-of-bounds and just clear the erase params when
>> passing zero for erase size.
>> While here avoid a superfluous dereference and use 'size' directly.
>>
>> UBSAN: shift-out-of-bounds in drivers/mtd/spi-nor/core.c:2237:24
>> shift exponent 4294967295 is too large for 32-bit type 'int'
>>
>> Fixes: 5390a8df769e ("mtd: spi-nor: add support to non-uniform SFDP SPI NOR
>> flash memories") Reported-by: Alexander Stein
>> <Alexander.Stein@...group.com>
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
>> ---
>> drivers/mtd/spi-nor/core.c | 9 +++++++--
>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
>> index 3d97c189c332..a1b5d5432f41 100644
>> --- a/drivers/mtd/spi-nor/core.c
>> +++ b/drivers/mtd/spi-nor/core.c
>> @@ -2230,8 +2230,13 @@ void spi_nor_set_erase_type(struct spi_nor_erase_type
>> *erase, u32 size, 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 (size) {
>> + erase->size_shift = ffs(size) - 1;
>> + erase->size_mask = (1 << erase->size_shift) - 1;
>> + } else {
>> + erase->size_shift = 0;
>> + erase->size_mask = 0;
>> + }
>> }
>>
>> /**
>
> What is the status of this patch? It is not applied up until now, no? Has it
> been superseeded?
>
I think it's marked with "changes requested". I'm going to send a v2.
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