[PATCH 5.8 07/16] net/smc: Prevent kernel-infoleak in __smc_diag_dump()

Greg Kroah-Hartman
2020-08-26T12:05:09Z

From: Peilin Ye <yepeilin.cs@gmail.com>

[ Upstream commit ce51f63e63c52a4e1eee4dd040fb0ba0af3b43ab ]

__smc_diag_dump() is potentially copying uninitialized kernel stack memory
into socket buffers, since the compiler may leave a 4-byte hole near the
beginning of `struct smcd_diag_dmbinfo`. Fix it by initializing `dinfo`
with memset().

Fixes: 4b1b7d3b30a6 ("net/smc: add SMC-D diag support")
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/smc/smc_diag.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

--- a/net/smc/smc_diag.c
+++ b/net/smc/smc_diag.c
@@ -170,13 +170,15 @@ static int __smc_diag_dump(struct sock *
(req->diag_ext & (1 << (SMC_DIAG_DMBINFO - 1))) &&
!list_empty(&smc->conn.lgr->list)) {
struct smc_connection *conn = &smc->conn;
- struct smcd_diag_dmbinfo dinfo = {
- .linkid = *((u32 *)conn->lgr->id),
- .peer_gid = conn->lgr->peer_gid,
- .my_gid = conn->lgr->smcd->local_gid,
- .token = conn->rmb_desc->token,
- .peer_token = conn->peer_token
- };
+ struct smcd_diag_dmbinfo dinfo;
+
+ memset(&dinfo, 0, sizeof(dinfo));
+
+ dinfo.linkid = *((u32 *)conn->lgr->id);
+ dinfo.peer_gid = conn->lgr->peer_gid;
+ dinfo.my_gid = conn->lgr->smcd->local_gid;
+ dinfo.token = conn->rmb_desc->token;
+ dinfo.peer_token = conn->peer_token;

if (nla_put(skb, SMC_DIAG_DMBINFO, sizeof(dinfo), &dinfo) < 0)
goto errout;