[PATCH 6.18 170/314] RDMA/irdma: Fix kernel stack leak in irdma_create_user_ah()

Sasha Levin
2026-03-10T11:27:22Z

From: Jason Gunthorpe <jgg@nvidia.com>

commit 74586c6da9ea222a61c98394f2fc0a604748438c upstream.

struct irdma_create_ah_resp { // 8 bytes, no padding
__u32 ah_id; // offset 0 - SET (uresp.ah_id = ah->sc_ah.ah_info.ah_idx)
__u8 rsvd[4]; // offset 4 - NEVER SET <- LEAK
};

rsvd[4]: 4 bytes of stack memory leaked unconditionally. Only ah_id is assigned before ib_respond_udata().

The reserved members of the structure were not zeroed.

Cc: stable@vger.kernel.org
Fixes: b48c24c2d710 ("RDMA/irdma: Implement device supported verb APIs")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://patch.msgid.link/3-v1-83e918d69e73+a9-rdma_udata_rc_jgg@nvidia.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/infiniband/hw/irdma/verbs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/irdma/verbs.c b/drivers/infiniband/hw/irdma/verbs.c
index b8655504da290..5d027c04dba6f 100644
--- a/drivers/infiniband/hw/irdma/verbs.c
+++ b/drivers/infiniband/hw/irdma/verbs.c
@@ -5202,7 +5202,7 @@ static int irdma_create_user_ah(struct ib_ah *ibah,
#define IRDMA_CREATE_AH_MIN_RESP_LEN offsetofend(struct irdma_create_ah_resp, rsvd)
struct irdma_ah *ah = container_of(ibah, struct irdma_ah, ibah);
struct irdma_device *iwdev = to_iwdev(ibah->pd->device);
- struct irdma_create_ah_resp uresp;
+ struct irdma_create_ah_resp uresp = {};
struct irdma_ah *parent_ah;
int err;

--
2.51.0