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@xxxxxxxxx> > Closes: https://lore.kernel.org/linux-ide/CA+-ZZ_jTgxh3bS7m+KX07_EWckSnW3N2adX3KV63y4g7M4CZ2A@xxxxxxxxxxxxxx/ > Signed-off-by: Niklas Cassel <cassel@xxxxxxxxxx> Looks good to me. But doesn't this need Fixes + Cc-stable tags ? > --- > drivers/ata/libata-sff.c | 18 ++++++++++-------- > 1 file changed, 10 insertions(+), 8 deletions(-) > > diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c > index 67f277e1c3bf..5a46c066abc3 100644 > --- a/drivers/ata/libata-sff.c > +++ b/drivers/ata/libata-sff.c > @@ -601,7 +601,7 @@ static void ata_pio_sector(struct ata_queued_cmd *qc) > { > struct ata_port *ap = qc->ap; > struct page *page; > - unsigned int offset; > + unsigned int offset, count; > > if (!qc->cursg) { > qc->curbytes = qc->nbytes; > @@ -617,25 +617,27 @@ static void ata_pio_sector(struct ata_queued_cmd *qc) > page = nth_page(page, (offset >> PAGE_SHIFT)); > offset %= PAGE_SIZE; > > - trace_ata_sff_pio_transfer_data(qc, offset, qc->sect_size); > + /* don't overrun current sg */ > + count = min(qc->cursg->length - qc->cursg_ofs, qc->sect_size); > + > + trace_ata_sff_pio_transfer_data(qc, offset, count); > > /* > * Split the transfer when it splits a page boundary. Note that the > * split still has to be dword aligned like all ATA data transfers. > */ > WARN_ON_ONCE(offset % 4); > - if (offset + qc->sect_size > PAGE_SIZE) { > + if (offset + count > PAGE_SIZE) { > unsigned int split_len = PAGE_SIZE - offset; > > ata_pio_xfer(qc, page, offset, split_len); > - ata_pio_xfer(qc, nth_page(page, 1), 0, > - qc->sect_size - split_len); > + ata_pio_xfer(qc, nth_page(page, 1), 0, count - split_len); > } else { > - ata_pio_xfer(qc, page, offset, qc->sect_size); > + ata_pio_xfer(qc, page, offset, count); > } > > - qc->curbytes += qc->sect_size; > - qc->cursg_ofs += qc->sect_size; > + qc->curbytes += count; > + qc->cursg_ofs += count; > > if (qc->cursg_ofs == qc->cursg->length) { > qc->cursg = sg_next(qc->cursg); -- Damien Le Moal Western Digital Research
