From 752ead44491e8c91e14d7079625c5916b30921c5 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 7 Aug 2019 12:23:57 -0600 Subject: [PATCH] libata: add SG safety checks in SFF pio transfers Abort processing of a command if we run out of mapped data in the SG list. This should never happen, but a previous bug caused it to be possible. Play it safe and attempt to abort nicely if we don't have more SG segments left. Reviewed-by: Kees Cook Signed-off-by: Jens Axboe --- drivers/ata/libata-sff.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c index 10aa27882142..4f115adb4ee8 100644 --- a/drivers/ata/libata-sff.c +++ b/drivers/ata/libata-sff.c @@ -658,6 +658,10 @@ static void ata_pio_sector(struct ata_queued_cmd *qc) unsigned int offset; unsigned char *buf; + if (!qc->cursg) { + qc->curbytes = qc->nbytes; + return; + } if (qc->curbytes == qc->nbytes - qc->sect_size) ap->hsm_task_state = HSM_ST_LAST; @@ -683,6 +687,8 @@ static void ata_pio_sector(struct ata_queued_cmd *qc) if (qc->cursg_ofs == qc->cursg->length) { qc->cursg = sg_next(qc->cursg); + if (!qc->cursg) + ap->hsm_task_state = HSM_ST_LAST; qc->cursg_ofs = 0; } } -- 2.30.2