2012-08-09 13:57:53

by Marina Makienko

Subject: [PATCH 01/13] block/paride: Potential null pointer dereference in pd_special_command()

The function blk_get_request() can return NULL in some cases. There are
checks on it if function is called with argumetns one of which is
GFP_ATOMIC/GFP_NOIO/etc. If system couldn't find request
blk_get_request() return NULL.

But if there is function call with argument __GFP_WAIT
the system will wait until get request or the queue becomes
dead. If something kills the queue, blk_get_request()
return NULL and next operations will lead to errors.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Marina Makienko <[email protected]>
---
drivers/block/paride/pd.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c
index 831e3ac..6e28910 100644
--- a/drivers/block/paride/pd.c
+++ b/drivers/block/paride/pd.c
@@ -723,6 +723,9 @@ static int pd_special_command(struct pd_unit *disk,

rq = blk_get_request(disk->gd->queue, READ, __GFP_WAIT);

+ if (!rq)
+ return Fail;
+
rq->cmd_type = REQ_TYPE_SPECIAL;
rq->special = func;

--
1.7.7

2012-08-09 13:57:55

by Marina Makienko

Subject: [PATCH 02/13] block: Potential null pointer dereference in pkt_generic_packet()

The function blk_get_request() can return NULL in some cases. There are
checks on it if function is called with argumetns one of which is
GFP_ATOMIC/GFP_NOIO/etc. If system couldn't find request
blk_get_request() return NULL.

But if there is function call with argument __GFP_WAIT
the system will wait until get request or the queue becomes
dead. If something kills the queue, blk_get_request()
return NULL and next operations will lead to errors.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Marina Makienko <[email protected]>
---
drivers/block/pktcdvd.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index ba66e44..be477aa 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -743,6 +743,9 @@ static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command *
rq = blk_get_request(q, (cgc->data_direction == CGC_DATA_WRITE) ?
WRITE : READ, __GFP_WAIT);

+ if (!rq)
+ return -EIO;
+
if (cgc->buflen) {
if (blk_rq_map_kern(q, rq, cgc->buffer, cgc->buflen, __GFP_WAIT))
goto out;
--
1.7.7