[PATCH v2] nvme-tcp: fix signedness bug in nvme_tcp_init_connection()

[Dan Carpenter]

The kernel_recvmsg() function returns an int which could be either
negative error codes or the number of bytes received.  The problem is
that the condition:

        if (ret < sizeof(*icresp)) {

is type promoted to type unsigned long and negative values are treated
as high positive values which is success, when they should be treated as
failure.  Handle invalid positive returns separately from negative
error codes to avoid this problem.

Fixes: 578539e09690 ("nvme-tcp: fix connect failure on receiving partial ICResp PDU")
Signed-off-by: Dan Carpenter <dan.carpenter at linaro.org>
Reviewed-by: Caleb Sander Mateos <csander at purestorage.com>
Reviewed-by: Sagi Grimberg <sagi at grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch at nvidia.com>
---
v2: Change the style.  Add the Reviewed-by tags.  (I will feel really bad
    if I introduced a bug in between v1 and v2 and cause everyone
    embarrassment with the R-b tags.)

 drivers/nvme/host/tcp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 8a9131c95a3d..b23ce31df97d 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1495,11 +1495,11 @@ static int nvme_tcp_init_connection(struct nvme_tcp_queue *queue)
 	msg.msg_flags = MSG_WAITALL;
 	ret = kernel_recvmsg(queue->sock, &msg, &iov, 1,
 			iov.iov_len, msg.msg_flags);
-	if (ret < sizeof(*icresp)) {
+	if (ret >= 0 && ret < sizeof(*icresp))
+		ret = -ECONNRESET;
+	if (ret < 0) {
 		pr_warn("queue %d: failed to receive icresp, error %d\n",
 			nvme_tcp_queue_id(queue), ret);
-		if (ret >= 0)
-			ret = -ECONNRESET;
 		goto free_icresp;
 	}
 	ret = -ENOTCONN;
-- 
2.47.2