linux-kernel - Re: [PATCH next] smb/client: Prevent error pointer dereference

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Message-ID: <CAH2r5mu=8vvqgD0KGb_WVFsP2c1dvOz=ePbWurF3A=AL=nQoWw@mail.gmail.com>
Date: Wed, 20 Nov 2024 14:13:17 -0600
From: Steve French <smfrench@...il.com>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: Ralph Boehme <slow@...ba.org>, Steve French <sfrench@...ba.org>, 
	Paulo Alcantara <pc@...guebit.com>, Ronnie Sahlberg <ronniesahlberg@...il.com>, 
	Shyam Prasad N <sprasad@...rosoft.com>, Tom Talpey <tom@...pey.com>, 
	Bharath SM <bharathsm@...rosoft.com>, linux-cifs@...r.kernel.org, 
	samba-technical@...ts.samba.org, linux-kernel@...r.kernel.org, 
	kernel-janitors@...r.kernel.org
Subject: Re: [PATCH next] smb/client: Prevent error pointer dereference

merged into cifs-2.6.git for-next

On Wed, Nov 20, 2024 at 11:18 AM Dan Carpenter <dan.carpenter@...aro.org> wrote:
>
> The cifs_sb_tlink() function can return error pointers, but this code
> dereferences it before checking for error pointers.  Re-order the code
> to fix that.
>
> Fixes: 0f9b6b045bb2 ("fs/smb/client: implement chmod() for SMB3 POSIX Extensions")
> Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
> ---
>  fs/smb/client/cifsacl.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/fs/smb/client/cifsacl.c b/fs/smb/client/cifsacl.c
> index c68ad526a4de..ba79aa2107cc 100644
> --- a/fs/smb/client/cifsacl.c
> +++ b/fs/smb/client/cifsacl.c
> @@ -1592,14 +1592,16 @@ id_mode_to_cifs_acl(struct inode *inode, const char *path, __u64 *pnmode,
>         struct smb_ntsd *pntsd = NULL; /* acl obtained from server */
>         struct smb_ntsd *pnntsd = NULL; /* modified acl to be sent to server */
>         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
> -       struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
> +       struct tcon_link *tlink;
>         struct smb_version_operations *ops;
>         bool mode_from_sid, id_from_sid;
> -       bool posix = tlink_tcon(tlink)->posix_extensions;
>         const u32 info = 0;
> +       bool posix;
>
> +       tlink = cifs_sb_tlink(cifs_sb);
>         if (IS_ERR(tlink))
>                 return PTR_ERR(tlink);
> +       posix = tlink_tcon(tlink)->posix_extensions;
>
>         ops = tlink_tcon(tlink)->ses->server->ops;
>
> --
> 2.45.2
>
>


-- 
Thanks,

Steve