[PATCH 6.0 0593/1073] RDMA/siw: Set defined status for work completion with undefined status

Greg Kroah-Hartman
2022-12-28T16:10:17Z

From: Bernard Metzler <bmt@zurich.ibm.com>

[ Upstream commit 60da2d11fcbc043304910e4d2ca82f9bab953e63 ]

A malicious user may write undefined values into memory mapped completion
queue elements status or opcode. Undefined status or opcode values will
result in out-of-bounds access to an array mapping siw internal
representation of opcode and status to RDMA core representation when
reaping CQ elements. While siw detects those undefined values, it did not
correctly set completion status to a defined value, thus defeating the
whole purpose of the check.

This bug leads to the following Smatch static checker warning:

drivers/infiniband/sw/siw/siw_cq.c:96 siw_reap_cqe()
error: buffer overflow 'map_cqe_status' 10 <= 21

Fixes: bdf1da5df9da ("RDMA/siw: Fix immediate work request flush to completion queue")
Link: https://lore.kernel.org/r/20221115170747.1263298-1-bmt@zurich.ibm.com
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/sw/siw/siw_cq.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/sw/siw/siw_cq.c b/drivers/infiniband/sw/siw/siw_cq.c
index acc7bcd538b5..403029de6b92 100644
--- a/drivers/infiniband/sw/siw/siw_cq.c
+++ b/drivers/infiniband/sw/siw/siw_cq.c
@@ -88,9 +88,9 @@ int siw_reap_cqe(struct siw_cq *cq, struct ib_wc *wc)

if (opcode >= SIW_NUM_OPCODES) {
opcode = 0;
- status = IB_WC_GENERAL_ERR;
+ status = SIW_WC_GENERAL_ERR;
} else if (status >= SIW_NUM_WC_STATUS) {
- status = IB_WC_GENERAL_ERR;
+ status = SIW_WC_GENERAL_ERR;
}
wc->opcode = map_wc_opcode[opcode];
wc->status = map_cqe_status[status].ib;
--
2.35.1