[PATCH 5.4 52/71] libata: if T_LENGTH is zero, dma direction should be DMA_NONE
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STALE1765d
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-12-20 14:52:04
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lkml
From: George Kennedy <redacted> commit 5da5231bb47864e5dd6c6731151e98b6ee498827 upstream. Avoid data corruption by rejecting pass-through commands where T_LENGTH is zero (No data is transferred) and the dma direction is not DMA_NONE. Cc: <redacted> Reported-by: syzkaller<redacted> Signed-off-by: George Kennedy<redacted> Signed-off-by: Damien Le Moal <redacted> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/ata/libata-scsi.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c@@ -3164,8 +3164,19 @@ static unsigned int ata_scsi_pass_thru(s goto invalid_fld; } - if (ata_is_ncq(tf->protocol) && (cdb[2 + cdb_offset] & 0x3) == 0) - tf->protocol = ATA_PROT_NCQ_NODATA; + if ((cdb[2 + cdb_offset] & 0x3) == 0) { + /* + * When T_LENGTH is zero (No data is transferred), dir should + * be DMA_NONE. + */ + if (scmd->sc_data_direction != DMA_NONE) { + fp = 2 + cdb_offset; + goto invalid_fld; + } + + if (ata_is_ncq(tf->protocol)) + tf->protocol = ATA_PROT_NCQ_NODATA; + } /* enable LBA */ tf->flags |= ATA_TFLAG_LBA;