[PATCH v2] smb: server: fix leak of ksmbd_ipc_login_request_ext() returned buffer

Free it unconditionally after ksmbd_alloc_user() calls.

kmemleak splat:
  unreferenced object 0xffff888103b83540 (size 192):
    comm "pool-0", pid 16970, jiffies 4377290937
    hex dump (first 32 bytes):
      00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00  ................
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace (crc 408ccc66):
      __kvmalloc_node_noprof+0x730/0x920
      handle_generic_event+0xec/0x1a0 [ksmbd]
      genl_family_rcv_msg_doit+0xe0/0x130
      genl_rcv_msg+0x181/0x290
      netlink_rcv_skb+0x4f/0x100
      genl_rcv+0x28/0x40
      netlink_unicast+0x1e6/0x2c0
      netlink_sendmsg+0x20a/0x450
      ____sys_sendmsg+0x2e8/0x310
      ___sys_sendmsg+0x78/0xc0
      __sys_sendmsg+0x63/0xc0
      do_syscall_64+0xa1/0x670
      entry_SYSCALL_64_after_hwframe+0x76/0x7e

Fixes: a77e0e02af1c ("ksmbd: add support for supplementary groups")
Signed-off-by: Enzo Matsumiya <[email protected]>
---
v2:
- use kvfree()
- move free to ksmbd_alloc_user() callers

 fs/smb/server/auth.c             | 1 +
 fs/smb/server/mgmt/user_config.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/fs/smb/server/auth.c b/fs/smb/server/auth.c
index 86f521e849d5..ffc4e1c8b287 100644
--- a/fs/smb/server/auth.c
+++ b/fs/smb/server/auth.c
@@ -436,6 +436,7 @@ int ksmbd_krb5_authenticate(struct ksmbd_session *sess, char *in_blob,
 		resp_ext = ksmbd_ipc_login_request_ext(resp->login_response.account);
 
 	user = ksmbd_alloc_user(&resp->login_response, resp_ext);
+	kvfree(resp_ext);
 	if (!user) {
 		ksmbd_debug(AUTH, "login failure\n");
 		retval = -ENOMEM;
diff --git a/fs/smb/server/mgmt/user_config.c b/fs/smb/server/mgmt/user_config.c
index cf45841d9d1b..03184a3303b9 100644
--- a/fs/smb/server/mgmt/user_config.c
+++ b/fs/smb/server/mgmt/user_config.c
@@ -26,6 +26,7 @@ struct ksmbd_user *ksmbd_login_user(const char *account)
 		resp_ext = ksmbd_ipc_login_request_ext(account);
 
 	user = ksmbd_alloc_user(resp, resp_ext);
+	kvfree(resp_ext);
 out:
 	kvfree(resp);
 	return user;
-- 
2.54.0