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Subject[PATCH 4.14 07/23] IB/hfi1: Fix possible null-pointer dereference in _extend_sdma_tx_descs()
Date
From: Tuo Li <islituo@gmail.com>

[ Upstream commit cbe71c61992c38f72c2b625b2ef25916b9f0d060 ]

kmalloc_array() is called to allocate memory for tx->descp. If it fails,
the function __sdma_txclean() is called:
__sdma_txclean(dd, tx);

However, in the function __sdma_txclean(), tx-descp is dereferenced if
tx->num_desc is not zero:
sdma_unmap_desc(dd, &tx->descp[0]);

To fix this possible null-pointer dereference, assign the return value of
kmalloc_array() to a local variable descp, and then assign it to tx->descp
if it is not NULL. Otherwise, go to enomem.

Fixes: 7724105686e7 ("IB/hfi1: add driver files")
Link: https://lore.kernel.org/r/20210806133029.194964-1-islituo@gmail.com
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
Tested-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Acked-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/hw/hfi1/sdma.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c
index 741938409f8e..c1c6d2c570aa 100644
--- a/drivers/infiniband/hw/hfi1/sdma.c
+++ b/drivers/infiniband/hw/hfi1/sdma.c
@@ -3067,6 +3067,7 @@ static void __sdma_process_event(struct sdma_engine *sde,
static int _extend_sdma_tx_descs(struct hfi1_devdata *dd, struct sdma_txreq *tx)
{
int i;
+ struct sdma_desc *descp;

/* Handle last descriptor */
if (unlikely((tx->num_desc == (MAX_DESC - 1)))) {
@@ -3087,12 +3088,10 @@ static int _extend_sdma_tx_descs(struct hfi1_devdata *dd, struct sdma_txreq *tx)
if (unlikely(tx->num_desc == MAX_DESC))
goto enomem;

- tx->descp = kmalloc_array(
- MAX_DESC,
- sizeof(struct sdma_desc),
- GFP_ATOMIC);
- if (!tx->descp)
+ descp = kmalloc_array(MAX_DESC, sizeof(struct sdma_desc), GFP_ATOMIC);
+ if (!descp)
goto enomem;
+ tx->descp = descp;

/* reserve last descriptor for coalescing */
tx->desc_limit = MAX_DESC - 1;
--
2.30.2


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