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

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Message-Id: <20210706120501.28776-1-colin.king@canonical.com>
Date:   Tue,  6 Jul 2021 13:05:01 +0100
From:   Colin King <colin.king@...onical.com>
To:     Namjae Jeon <namjae.jeon@...sung.com>,
        Sergey Senozhatsky <senozhatsky@...omium.org>,
        Steve French <sfrench@...ba.org>,
        Hyunchul Lee <hyc.lee@...il.com>, linux-cifs@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] ksmbd: Fix read on the uninitialized pointer sess

From: Colin Ian King <colin.king@...onical.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@...onical.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