[PATCH][next] ksmbd: Fix read on the uninitialized pointer sess

[PATCH][next] ksmbd: Fix read on the uninitialized pointer sess

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

There is a error handling case that passes control to label out_err
without pointer sess being assigned a value. The unassigned pointer
may be any garbage value and so the test of rc < 0 && sess maybe
true leading to sess being passed to the call to ksmbd_session_destroy.
Fix this by setting sess to NULL in this corner case.

Addresses-Coverity: ("Uninitialized pointer read")
Fixes: f5a544e3bab7 ("ksmbd: add support for SMB3 multichannel")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 fs/ksmbd/smb2pdu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index dda90812feef..ad976dbbb0b6 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -1615,6 +1615,7 @@ int smb2_sess_setup(struct ksmbd_work *work)
 	} else if ((conn->dialect < SMB30_PROT_ID ||
 		    server_conf.flags & KSMBD_GLOBAL_FLAG_SMB3_MULTICHANNEL) &&
 		   (req->Flags & SMB2_SESSION_REQ_FLAG_BINDING)) {
+		sess = NULL;
 		rc = -EACCES;
 		goto out_err;
 	} else {
-- 
2.31.1

Re: [PATCH][next] ksmbd: Fix read on the uninitialized pointer sess

[Namjae Jeon]

Hi Colin,

2021-07-06 21:05 GMT+09:00, Colin King <colin.king@canonical.com>:
> From: Colin Ian King <colin.king@canonical.com>
>
> There is a error handling case that passes control to label out_err
> without pointer sess being assigned a value. The unassigned pointer
> may be any garbage value and so the test of rc < 0 && sess maybe
> true leading to sess being passed to the call to ksmbd_session_destroy.
> Fix this by setting sess to NULL in this corner case.
>
> Addresses-Coverity: ("Uninitialized pointer read")
> Fixes: f5a544e3bab7 ("ksmbd: add support for SMB3 multichannel")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
I will apply this patch. Thanks for your patch!