[PATCH 5.6 062/167] tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv

[Greg Kroah-Hartman]

From: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>

[ Upstream commit 441870ee4240cf67b5d3ab8e16216a9ff42eb5d6 ]

tipc_crypto_rcv() invokes tipc_aead_get(), which returns a reference of
the tipc_aead object to "aead" with increased refcnt.

When tipc_crypto_rcv() returns, the original local reference of "aead"
becomes invalid, so the refcount should be decreased to keep refcount
balanced.

The issue happens in one error path of tipc_crypto_rcv(). When TIPC
message decryption status is EINPROGRESS or EBUSY, the function forgets
to decrease the refcnt increased by tipc_aead_get() and causes a refcnt
leak.

Fix this issue by calling tipc_aead_put() on the error path when TIPC
message decryption status is EINPROGRESS or EBUSY.

Signed-off-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/tipc/crypto.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/tipc/crypto.c
+++ b/net/tipc/crypto.c
@@ -1712,6 +1712,7 @@ exit:
 	case -EBUSY:
 		this_cpu_inc(stats->stat[STAT_ASYNC]);
 		*skb = NULL;
+		tipc_aead_put(aead);
 		return rc;
 	default:
 		this_cpu_inc(stats->stat[STAT_NOK]);