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[ Upstream commita4b6539038
] When recvmsg with MSG_PEEK flag, the data will be copied to user's buffer without advancing consume cursor and without reducing the length of rx available data. Once the expected peek length is larger than the value of bytes_to_rcv, in the loop of do while in smc_rx_recvmsg, the first loop will copy bytes_to_rcv bytes of data from the position local_tx_ctrl.cons, the second loop will copy the min(bytes_to_rcv, read_remaining) bytes from the position local_tx_ctrl.cons again because of the lacking of process with advancing consume cursor and reducing the length of available data. So do the subsequent loops. The data copied in the second loop and the subsequent loops will result in data error, as it should not be copied if no more data arrives and it should be copied from the position advancing bytes_to_rcv bytes from the local_tx_ctrl.cons if more data arrives. This issue can be reproduce by the following python script: server.py: import socket import time server_ip = '0.0.0.0' server_port = 12346 server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) server_socket.bind((server_ip, server_port)) server_socket.listen(1) print('Server is running and listening for connections...') conn, addr = server_socket.accept() print('Connected by', addr) while True: data = conn.recv(1024) if not data: break print('Received request:', data.decode()) conn.sendall(b'Hello, client!\n') time.sleep(5) conn.sendall(b'Hello, again!\n') conn.close() client.py: import socket server_ip = '<server ip>' server_port = 12346 resp=b'Hello, client!\nHello, again!\n' client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) client_socket.connect((server_ip, server_port)) request = 'Hello, server!' client_socket.sendall(request.encode()) peek_data = client_socket.recv(len(resp), socket.MSG_PEEK | socket.MSG_WAITALL) print('Peeked data:', peek_data.decode()) client_socket.close() Fixes:952310ccf2
("smc: receive data from RMBE") Reported-by: D. Wythe <alibuda@linux.alibaba.com> Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com> Link: https://patch.msgid.link/20250104143201.35529-1-guangguan.wang@linux.alibaba.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
32 lines
771 B
C
32 lines
771 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Shared Memory Communications over RDMA (SMC-R) and RoCE
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*
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* Manage RMBE
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*
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* Copyright IBM Corp. 2016
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*
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* Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
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*/
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#ifndef SMC_RX_H
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#define SMC_RX_H
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#include <linux/socket.h>
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#include <linux/types.h>
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#include "smc.h"
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void smc_rx_init(struct smc_sock *smc);
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int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg,
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struct pipe_inode_info *pipe, size_t len, int flags);
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int smc_rx_wait(struct smc_sock *smc, long *timeo, size_t peeked,
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int (*fcrit)(struct smc_connection *conn, size_t baseline));
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static inline int smc_rx_data_available(struct smc_connection *conn, size_t peeked)
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{
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return atomic_read(&conn->bytes_to_rcv) - peeked;
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}
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#endif /* SMC_RX_H */
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