[linux-cifs-client] [PATCH 4/6] [CIFS] change cifs_setup_session to take a unc string arg

[Q (Igor Mammedov)]

Wouldn't it be better if we saved hostname portion of unc in some field 
of TCP_Server_Info struct? That would result in more reusability of it 
in future and we wouldn't have to change signatures whenever we wish to 
use it.

Jeff Layton wrote:
> ...then extract the host portion of the UNC string so that we can
> use in SPNEGO.
> 
> Signed-off-by: Jeff Layton <jlayton at redhat.com>
> ---
>  fs/cifs/cifsproto.h |    2 +-
>  fs/cifs/cifssmb.c   |    6 ++++--
>  fs/cifs/connect.c   |   46 ++++++++++++++++++++++++++++++++++++++++++++--
>  3 files changed, 49 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index dd1d7c2..b256e8a 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -107,7 +107,7 @@ void cifs_proc_init(void);
>  void cifs_proc_clean(void);
>  
>  extern int cifs_setup_session(unsigned int xid, struct cifsSesInfo *pSesInfo,
> -			struct nls_table *nls_info);
> +			struct nls_table *nls_info, const char *unc);
>  extern int CIFSSMBNegotiate(unsigned int xid, struct cifsSesInfo *ses);
>  
>  extern int CIFSTCon(unsigned int xid, struct cifsSesInfo *ses,
> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> index 0bb3e43..49ad995 100644
> --- a/fs/cifs/cifssmb.c
> +++ b/fs/cifs/cifssmb.c
> @@ -157,7 +157,8 @@ small_smb_init(int smb_command, int wct, struct cifsTconInfo *tcon,
>  			down(&tcon->ses->sesSem);
>  			if (tcon->ses->status == CifsNeedReconnect)
>  				rc = cifs_setup_session(0, tcon->ses,
> -							nls_codepage);
> +							nls_codepage,
> +							tcon->treeName);
>  			if (!rc && (tcon->tidStatus == CifsNeedReconnect)) {
>  				mark_open_files_invalid(tcon);
>  				rc = CIFSTCon(0, tcon->ses, tcon->treeName,
> @@ -302,7 +303,8 @@ smb_init(int smb_command, int wct, struct cifsTconInfo *tcon,
>  			down(&tcon->ses->sesSem);
>  			if (tcon->ses->status == CifsNeedReconnect)
>  				rc = cifs_setup_session(0, tcon->ses,
> -							nls_codepage);
> +							nls_codepage,
> +							tcon->treeName);
>  			if (!rc && (tcon->tidStatus == CifsNeedReconnect)) {
>  				mark_open_files_invalid(tcon);
>  				rc = CIFSTCon(0, tcon->ses, tcon->treeName,
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 380ee99..14b564e 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -1996,7 +1996,8 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
>  			down(&pSesInfo->sesSem);
>  			/* BB FIXME need to pass vol->secFlgs BB */
>  			rc = cifs_setup_session(xid, pSesInfo,
> -						cifs_sb->local_nls);
> +						cifs_sb->local_nls,
> +						volume_info.UNC);
>  			up(&pSesInfo->sesSem);
>  			if (!rc)
>  				atomic_inc(&srvTcp->socketUseCount);
> @@ -3508,13 +3509,51 @@ cifs_umount(struct super_block *sb, struct cifs_sb_info *cifs_sb)
>  	return rc;	/* BB check if we should always return zero here */
>  }
>  
> +/* extract the host portion of the UNC string */
> +static char *
> +extract_hostname_from_unc(const char *unc)
> +{
> +	const char *src;
> +	char *dst, *delim;
> +	unsigned int len;
> +
> +	/* skip double chars at beginning of string */
> +	/* BB: check validity of these bytes? */
> +	src = unc + 2;
> +
> +	delim = strchr(src, '/');
> +	if (!delim) {
> +		delim = strchr(src, '\\');
> +		if (!delim)
> +			return ERR_PTR(-EINVAL);
> +	}
> +
> +	len = delim - src;
> +	dst = kmalloc((len + 1), GFP_KERNEL);
> +	if (dst == NULL)
> +		return ERR_PTR(-ENOMEM);
> +
> +	memcpy(dst, src, len);
> +	dst[len] = '\0';
> +
> +	return dst;
> +}
> +
>  int cifs_setup_session(unsigned int xid, struct cifsSesInfo *pSesInfo,
> -					   struct nls_table *nls_info)
> +			struct nls_table *nls_info, const char *unc)
>  {
>  	int rc = 0;
>  	char ntlm_session_key[CIFS_SESS_KEY_SIZE];
>  	int ntlmv2_flag = FALSE;
>  	int first_time = 0;
> +	char *hostname;
> +
> +	hostname = extract_hostname_from_unc(unc);
> +	if (IS_ERR(hostname)) {
> +		rc = PTR_ERR(hostname);
> +		hostname = NULL;
> +		goto ss_err_exit;
> +	}
>  
>  	/* what if server changes its buffer size after dropping the session? */
>  	if (pSesInfo->server->maxBuf == 0) /* no need to send on reconnect */ {
> @@ -3627,6 +3666,9 @@ int cifs_setup_session(unsigned int xid, struct cifsSesInfo *pSesInfo,
>  		}
>  	}
>  ss_err_exit:
> +	if (hostname)
> +		kfree(hostname);
> +
>  	return rc;
>  }
>  


-- 

Best regards,

-------------------------
Igor Mammedov,
niallain "at" gmail.com