Re: [PATCH] ata: libata-sff: Ensure that we cannot write outside the allocated buffer

[Niklas Cassel <cassel@kernel.org>]

On Sat, Jan 25, 2025 at 08:12:38AM +0900, Damien Le Moal wrote:
> On 1/24/25 23:11, Niklas Cassel wrote:
> > reveliofuzzing reported that a SCSI_IOCTL_SEND_COMMAND ioctl with out_len
> > set to 0xd42, SCSI command set to ATA_16 PASS-THROUGH, ATA command set to
> > ATA_NOP, and protocol set to ATA_PROT_PIO, can cause ata_pio_sector() to
> > write outside the allocated buffer, overwriting random memory.
> > 
> > While a ATA device is supposed to abort a ATA_NOP command, there does seem
> > to be a bug either in libata-sff or QEMU, where either this status is not
> > set, or the status is cleared before read by ata_sff_hsm_move().
> > Anyway, that is most likely a separate bug.
> > 
> > Looking at __atapi_pio_bytes(), it already has a safety check to ensure
> > that __atapi_pio_bytes() cannot write outside the allocated buffer.
> > 
> > Add a similar check to ata_pio_sector(), such that also ata_pio_sector()
> > cannot write outside the allocated buffer.
> > 
> > Reported-by: reveliofuzzing <reveliofuzzing@gmail.com>
> > Closes: https://lore.kernel.org/linux-ide/CA+-ZZ_jTgxh3bS7m+KX07_EWckSnW3N2adX3KV63y4g7M4CZ2A@mail.gmail.com/
> > Signed-off-by: Niklas Cassel <cassel@kernel.org>
> 
> Looks good to me. But doesn't this need Fixes + Cc-stable tags ?

ata_pio_sector() has been able to write more data than what fits in the
buffer since the commit that imported linux into git:
1da177e4c3f4 ("Linux-2.6.12-rc2")

although ata_pio_sector() then lived in: drivers/scsi/libata-core.c

Do you want me to use this as the Fixes tag?


Kind regards,
Niklas