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From:   Hangyu Hua <hbh25y@gmail.com>
To:     bvanassche@acm.org, jgg@ziepe.ca, leon@kernel.org,
        gustavoars@kernel.org
Cc:     linux-rdma@vger.kernel.org, target-devel@vger.kernel.org,
        linux-kernel@vger.kernel.org, Hangyu Hua <hbh25y@gmail.com>
Subject: [PATCH] infiniband: ulp: srpt: Use flex array destination for memcpy()
Date:   Fri,  9 Sep 2022 10:29:43 +0800
Message-Id: <20220909022943.8896-1-hbh25y@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In preparation for FORTIFY_SOURCE performing run-time destination buffer
bounds checking for memcpy(), specify the destination output buffer
explicitly, instead of asking memcpy() to write past the end of what looked
like a fixed-size object.

Notice that srp_rsp[] is a pointer to a structure that contains
flexible-array member data[]:

struct srp_rsp {
	...
	__be32	sense_data_len;
	__be32	resp_data_len;
	u8	data[];
};

link: https://github.com/KSPP/linux/issues/201
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 21cbe30d526f..8c29e14150d3 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -1421,7 +1421,7 @@ static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
 
 		srp_rsp->flags |= SRP_RSP_FLAG_SNSVALID;
 		srp_rsp->sense_data_len = cpu_to_be32(sense_data_len);
-		memcpy(srp_rsp + 1, sense_data, sense_data_len);
+		memcpy(srp_rsp->data, sense_data, sense_data_len);
 	}
 
 	return sizeof(*srp_rsp) + sense_data_len;
-- 
2.34.1