[PATCH v4 2/3] SUNRPC: Fix leak of krb5p encode pages

[Trond Myklebust <trondmy@gmail.com>]

From: Chuck Lever <chuck.lever@oracle.com>

call_encode can be invoked more than once per RPC call. Ensure that
each call to gss_wrap_req_priv does not overwrite pointers to
previously allocated memory.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 net/sunrpc/auth_gss/auth_gss.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 5d3f252659f1..ba765473d1f0 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1791,6 +1791,7 @@ priv_release_snd_buf(struct rpc_rqst *rqstp)
 	for (i=0; i < rqstp->rq_enc_pages_num; i++)
 		__free_page(rqstp->rq_enc_pages[i]);
 	kfree(rqstp->rq_enc_pages);
+	rqstp->rq_release_snd_buf = NULL;
 }
 
 static int
@@ -1799,6 +1800,9 @@ alloc_enc_pages(struct rpc_rqst *rqstp)
 	struct xdr_buf *snd_buf = &rqstp->rq_snd_buf;
 	int first, last, i;
 
+	if (rqstp->rq_release_snd_buf)
+		rqstp->rq_release_snd_buf(rqstp);
+
 	if (snd_buf->page_len == 0) {
 		rqstp->rq_enc_pages_num = 0;
 		return 0;
-- 
2.19.2