2018-04-03 21:24:16

by Gustavo A. R. Silva

Subject: [PATCH] cifs: cifssmb: Fix potential NULL pointer dereference

tcon->ses is being dereferenced before it is null checked, hence
there is a potential null pointer dereference.

Fix this by moving the pointer dereference after tcon->ses has
been properly null checked.

Addresses-Coverity-ID: 1467426 ("Dereference before null check")
Fixes: 93012bf98416 ("cifs: add server->vals->header_preamble_size")
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
fs/cifs/smb2pdu.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index f7741ce..e5ac474 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3454,7 +3454,7 @@ static int
build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon, int level,
int outbuf_len, u64 persistent_fid, u64 volatile_fid)
{
- struct TCP_Server_Info *server = tcon->ses->server;
+ struct TCP_Server_Info *server;
int rc;
struct smb2_query_info_req *req;
unsigned int total_len;
@@ -3464,6 +3464,8 @@ build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon, int level,
if ((tcon->ses == NULL) || (tcon->ses->server == NULL))
return -EIO;

+ server = tcon->ses->server;
+
rc = smb2_plain_req_init(SMB2_QUERY_INFO, tcon, (void **) &req,
&total_len);
if (rc)
--
2.7.4

2018-04-03 21:03:52

by Gustavo A. R. Silva

Subject: Re: [PATCH] cifs: cifssmb: Fix potential NULL pointer dereference

Hi,

I noticed the subject was incorrect. Drop this patch, please.

I just sent v2.

Thanks
--
Gustavo

On 04/03/2018 03:55 PM, Gustavo A. R. Silva wrote:
> tcon->ses is being dereferenced before it is null checked, hence
> there is a potential null pointer dereference.
>
> Fix this by moving the pointer dereference after tcon->ses has
> been properly null checked.
>
> Addresses-Coverity-ID: 1467426 ("Dereference before null check")
> Fixes: 93012bf98416 ("cifs: add server->vals->header_preamble_size")
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
> fs/cifs/smb2pdu.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index f7741ce..e5ac474 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -3454,7 +3454,7 @@ static int
> build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon, int level,
> int outbuf_len, u64 persistent_fid, u64 volatile_fid)
> {
> - struct TCP_Server_Info *server = tcon->ses->server;
> + struct TCP_Server_Info *server;
> int rc;
> struct smb2_query_info_req *req;
> unsigned int total_len;
> @@ -3464,6 +3464,8 @@ build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon, int level,
> if ((tcon->ses == NULL) || (tcon->ses->server == NULL))
> return -EIO;
>
> + server = tcon->ses->server;
> +
> rc = smb2_plain_req_init(SMB2_QUERY_INFO, tcon, (void **) &req,
> &total_len);
> if (rc)
>