From: Steve French <smfrench@gmail.com>
To: Colin King <colin.king@canonical.com>
Cc: Steve French <sfrench@samba.org>,
CIFS <linux-cifs@vger.kernel.org>,
samba-technical <samba-technical@lists.samba.org>,
kernel-janitors <kernel-janitors@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH][V2][cifs-next] cifs: fix dereference on ses before it is null checked
Date: Mon, 2 Sep 2019 14:42:34 -0500 [thread overview]
Message-ID: <CAH2r5mv_Fv_k8h=-i8-bBrgBU3ghCVM3W=KyLrL=LrrCiT=vOQ@mail.gmail.com> (raw)
In-Reply-To: <20190902151059.22088-1-colin.king@canonical.com>
Tentatively merged into cifs-2.6.git pending additional testing
Kicked off buildbot with rc7+patches in cifs for-next
See http://smb3-test-rhel-75.southcentralus.cloudapp.azure.com/#/builders/2/builds/247
On Mon, Sep 2, 2019 at 10:33 AM Colin King <colin.king@canonical.com> wrote:
>
> From: Colin Ian King <colin.king@canonical.com>
>
> The assignment of pointer server dereferences pointer ses, however,
> this dereference occurs before ses is null checked and hence we
> have a potential null pointer dereference. Fix this by only
> dereferencing ses after it has been null checked.
>
> Addresses-Coverity: ("Dereference before null check")
> Fixes: 2808c6639104 ("cifs: add new debugging macro cifs_server_dbg")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> fs/cifs/smb2pdu.c | 11 ++++++++---
> fs/cifs/transport.c | 3 ++-
> 2 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index dbc6ef50dd45..0e92983de0b7 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -2759,8 +2759,10 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
> else
> return -EIO;
>
> + if (!ses)
> + return -EIO;
> server = ses->server;
> - if (!ses || !(server))
> + if (!server)
> return -EIO;
>
> if (smb3_encryption_required(tcon))
> @@ -3058,13 +3060,16 @@ query_info(const unsigned int xid, struct cifs_tcon *tcon,
> int rc = 0;
> int resp_buftype = CIFS_NO_BUFFER;
> struct cifs_ses *ses = tcon->ses;
> - struct TCP_Server_Info *server = ses->server;
> + struct TCP_Server_Info *server;
> int flags = 0;
> bool allocated = false;
>
> cifs_dbg(FYI, "Query Info\n");
>
> - if (!ses || !(server))
> + if (!ses)
> + return -EIO;
> + server = ses->server;
> + if (!server)
> return -EIO;
>
> if (smb3_encryption_required(tcon))
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index 0d60bd2f4dca..a90bd4d75b4d 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -1242,12 +1242,13 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
> struct kvec iov = { .iov_base = in_buf, .iov_len = len };
> struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 };
> struct cifs_credits credits = { .value = 1, .instance = 0 };
> - struct TCP_Server_Info *server = ses->server;
> + struct TCP_Server_Info *server;
>
> if (ses == NULL) {
> cifs_dbg(VFS, "Null smb session\n");
> return -EIO;
> }
> + server = ses->server;
> if (server == NULL) {
> cifs_dbg(VFS, "Null tcp session\n");
> return -EIO;
> --
> 2.20.1
>
--
Thanks,
Steve
prev parent reply other threads:[~2019-09-02 19:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-02 15:10 [PATCH][V2][cifs-next] cifs: fix dereference on ses before it is null checked Colin King
2019-09-02 19:42 ` Steve French [this message]
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