[PATCH AUTOSEL 6.0 05/30] SUNRPC: Fix crasher in gss_unwrap_resp_integ()

[Sasha Levin]

From: Chuck Lever <chuck.lever@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/sunrpc/auth_gss/auth_gss.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index a31a27816cc0..7bb247c51e2f 100644
--- 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;
-- 
2.35.1