[PATCH AUTOSEL 5.4 286/350] RDMA/efa: Clear the admin command buffer prior to its submission

[Sasha Levin]

From: Gal Pressman <galpress@xxxxxxxxxx>

[ Upstream commit 64c264872b8879e2ab9017eefe9514d4c045c60e ]

We cannot rely on the entry memcpy as we only copy the actual size of the
command, the rest of the bytes must be memset to zero.

Currently providing non-zero memory will not have any user visible impact.
However, since admin commands are extendable (in a backwards compatible
way) everything beyond the size of the command must be cleared to prevent
issues in the future.

Fixes: 0420e542569b ("RDMA/efa: Implement functions that submit and complete admin commands")
Link: https://lore.kernel.org/r/20191112092608.46964-1-galpress@xxxxxxxxxx
Reviewed-by: Daniel Kranzdorf <dkkranzd@xxxxxxxxxx>
Reviewed-by: Firas JahJah <firasj@xxxxxxxxxx>
Signed-off-by: Gal Pressman <galpress@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/infiniband/hw/efa/efa_com.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/efa/efa_com.c b/drivers/infiniband/hw/efa/efa_com.c
index 3c412bc5b94f1..0778f4f7dccd7 100644
--- a/drivers/infiniband/hw/efa/efa_com.c
+++ b/drivers/infiniband/hw/efa/efa_com.c
@@ -317,6 +317,7 @@ static struct efa_comp_ctx *__efa_com_submit_admin_cmd(struct efa_com_admin_queu
 						       struct efa_admin_acq_entry *comp,
 						       size_t comp_size_in_bytes)
 {
+	struct efa_admin_aq_entry *aqe;
 	struct efa_comp_ctx *comp_ctx;
 	u16 queue_size_mask;
 	u16 cmd_id;
@@ -350,7 +351,9 @@ static struct efa_comp_ctx *__efa_com_submit_admin_cmd(struct efa_com_admin_queu
 
 	reinit_completion(&comp_ctx->wait_event);
 
-	memcpy(&aq->sq.entries[pi], cmd, cmd_size_in_bytes);
+	aqe = &aq->sq.entries[pi];
+	memset(aqe, 0, sizeof(*aqe));
+	memcpy(aqe, cmd, cmd_size_in_bytes);
 
 	aq->sq.pc++;
 	atomic64_inc(&aq->stats.submitted_cmd);
-- 
2.20.1