net/smc: check return value of sock_recvmsg when draining clc data

[ Upstream commit c5b8ee5022a19464783058dc6042e8eefa34e8cd ]

When receiving clc msg, the field length in smc_clc_msg_hdr indicates the
length of msg should be received from network and the value should not be
fully trusted as it is from the network. Once the value of length exceeds
the value of buflen in function smc_clc_wait_msg it may run into deadloop
when trying to drain the remaining data exceeding buflen.

This patch checks the return value of sock_recvmsg when draining data in
case of deadloop in draining.

Fixes: fb4f79264c0f ("net/smc: tolerate future SMCD versions")
Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
Reviewed-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: D. Wythe <alibuda@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index f734fdd90c81138980a44bee7e886cc049886d99..a48fdc83fe6b2cf3ec8f3fcbc0fac2d335a21f4e 100644 (file)
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -753,6 +753,11 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
                                                SMC_CLC_RECV_BUF_LEN : datlen;
                iov_iter_kvec(&msg.msg_iter, ITER_DEST, &vec, 1, recvlen);
                len = sock_recvmsg(smc->clcsock, &msg, krflags);
+               if (len < recvlen) {
+                       smc->sk.sk_err = EPROTO;
+                       reason_code = -EPROTO;
+                       goto out;
+               }
                datlen -= len;
        }
        if (clcm->type == SMC_CLC_DECLINE) {