SUNRPC: Fix crasher in gss_unwrap_resp_integ()

[ Upstream commit 8a0fa3ff3b606b55c4edc71ad133e61529b64549 ]

If a zero length is passed to kmalloc() it returns 0x10, which is
not a valid address. gss_unwrap_resp_integ() subsequently crashes
when it attempts to dereference that pointer.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index a31a27816cc0f8bdcbefe751a0eb1e8dc60bbf5e..7bb247c51e2f66e7b8968c4cf054ed238aacf2b8 100644 (file)
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1989,7 +1989,7 @@ gss_unwrap_resp_integ(struct rpc_task *task, struct rpc_cred *cred,
                goto unwrap_failed;
        mic.len = len;
        mic.data = kmalloc(len, GFP_KERNEL);
-       if (!mic.data)
+       if (ZERO_OR_NULL_PTR(mic.data))
                goto unwrap_failed;
        if (read_bytes_from_xdr_buf(rcv_buf, offset, mic.data, mic.len))
                goto unwrap_failed;