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Commit c7c137b9 authored by Steve French's avatar Steve French
Browse files

smb3: do not allow insecure cifs mounts when using smb3 



if mounting as smb3 do not allow cifs (vers=1.0) or insecure vers=2.0
mounts.

For example:
root@smf-Thinkpad-P51:~/cifs-2.6# mount -t smb3 //127.0.0.1/scratch /mnt -o username=testuser,password=Testpass1
root@smf-Thinkpad-P51:~/cifs-2.6# umount /mnt
root@smf-Thinkpad-P51:~/cifs-2.6# mount -t smb3 //127.0.0.1/scratch /mnt -o username=testuser,password=Testpass1,vers=1.0
mount: /mnt: wrong fs type, bad option, bad superblock on //127.0.0.1/scratch ...
root@smf-Thinkpad-P51:~/cifs-2.6# dmesg | grep smb3
[ 4302.200122] CIFS VFS: vers=1.0 (cifs) not permitted when mounting with smb3
root@smf-Thinkpad-P51:~/cifs-2.6# mount -t smb3 //127.0.0.1/scratch /mnt -o username=testuser,password=Testpass1,vers=3.11

Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
Acked-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: default avatarAurelien Aptel <aaptel@suse.com>
Reviewed-by: default avatarSachin Prabhu <sprabhu@redhat.com>
parent 8ddecf5f

fs/cifs/cifsfs.c

+18 −4
Original line number Diff line number Diff line
@@ -698,8 +698,8 @@ static int cifs_set_super(struct super_block *sb, void *data) 
}



static struct dentry *

cifs_do_mount(struct file_system_type *fs_type,

	      int flags, const char *dev_name, void *data)

cifs_smb3_do_mount(struct file_system_type *fs_type,

	      int flags, const char *dev_name, void *data, bool is_smb3)

{

	int rc;

	struct super_block *sb;
@@ -710,7 +710,7 @@ cifs_do_mount(struct file_system_type *fs_type, 


	cifs_dbg(FYI, "Devname: %s flags: %d\n", dev_name, flags);



	volume_info = cifs_get_volume_info((char *)data, dev_name);

	volume_info = cifs_get_volume_info((char *)data, dev_name, is_smb3);

	if (IS_ERR(volume_info))

		return ERR_CAST(volume_info);
@@ -790,6 +790,20 @@ cifs_do_mount(struct file_system_type *fs_type, 
	goto out;

}



static struct dentry *

smb3_do_mount(struct file_system_type *fs_type,

	      int flags, const char *dev_name, void *data)

{

	return cifs_smb3_do_mount(fs_type, flags, dev_name, data, true);

}



static struct dentry *

cifs_do_mount(struct file_system_type *fs_type,

	      int flags, const char *dev_name, void *data)

{

	return cifs_smb3_do_mount(fs_type, flags, dev_name, data, false);

}



static ssize_t

cifs_loose_read_iter(struct kiocb *iocb, struct iov_iter *iter)

{
@@ -925,7 +939,7 @@ MODULE_ALIAS_FS("cifs"); 
static struct file_system_type smb3_fs_type = {

	.owner = THIS_MODULE,

	.name = "smb3",

	.mount = cifs_do_mount,

	.mount = smb3_do_mount,

	.kill_sb = cifs_kill_sb,

	/*  .fs_flags */

};

fs/cifs/cifsproto.h

+1 −1
Original line number Diff line number Diff line
@@ -211,7 +211,7 @@ extern int cifs_setup_cifs_sb(struct smb_vol *pvolume_info, 
extern int cifs_match_super(struct super_block *, void *);

extern void cifs_cleanup_volume_info(struct smb_vol *pvolume_info);

extern struct smb_vol *cifs_get_volume_info(char *mount_data,

					    const char *devname);

					    const char *devname, bool is_smb3);

extern int cifs_mount(struct cifs_sb_info *, struct smb_vol *);

extern void cifs_umount(struct cifs_sb_info *);

extern void cifs_mark_open_files_invalid(struct cifs_tcon *tcon);

fs/cifs/connect.c

+17 −9
Original line number Diff line number Diff line
@@ -320,7 +320,7 @@ static int generic_ip_connect(struct TCP_Server_Info *server); 
static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);

static void cifs_prune_tlinks(struct work_struct *work);

static int cifs_setup_volume_info(struct smb_vol *volume_info, char *mount_data,

					const char *devname);

					const char *devname, bool is_smb3);



/*

 * cifs tcp session reconnection
@@ -1166,7 +1166,7 @@ cifs_parse_cache_flavor(char *value, struct smb_vol *vol) 
}



static int

cifs_parse_smb_version(char *value, struct smb_vol *vol)

cifs_parse_smb_version(char *value, struct smb_vol *vol, bool is_smb3)

{

	substring_t args[MAX_OPT_ARGS];
@@ -1176,6 +1176,10 @@ cifs_parse_smb_version(char *value, struct smb_vol *vol) 
			cifs_dbg(VFS, "mount with legacy dialect disabled\n");

			return 1;

		}

		if (is_smb3) {

			cifs_dbg(VFS, "vers=1.0 (cifs) not permitted when mounting with smb3\n");

			return 1;

		}

		vol->ops = &smb1_operations;

		vol->vals = &smb1_values;

		break;
@@ -1184,6 +1188,10 @@ cifs_parse_smb_version(char *value, struct smb_vol *vol) 
			cifs_dbg(VFS, "mount with legacy dialect disabled\n");

			return 1;

		}

		if (is_smb3) {

			cifs_dbg(VFS, "vers=2.0 not permitted when mounting with smb3\n");

			return 1;

		}

		vol->ops = &smb20_operations;

		vol->vals = &smb20_values;

		break;
@@ -1272,7 +1280,7 @@ cifs_parse_devname(const char *devname, struct smb_vol *vol) 


static int

cifs_parse_mount_options(const char *mountdata, const char *devname,

			 struct smb_vol *vol)

			 struct smb_vol *vol, bool is_smb3)

{

	char *data, *end;

	char *mountdata_copy = NULL, *options;
@@ -1985,7 +1993,7 @@ cifs_parse_mount_options(const char *mountdata, const char *devname, 
			if (string == NULL)

				goto out_nomem;



			if (cifs_parse_smb_version(string, vol) != 0)

			if (cifs_parse_smb_version(string, vol, is_smb3) != 0)

				goto cifs_parse_mount_err;

			got_version = true;

			break;
@@ -3797,7 +3805,7 @@ expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses, 
		} else {

			cleanup_volume_info_contents(volume_info);

			rc = cifs_setup_volume_info(volume_info, mdata,

							fake_devname);

							fake_devname, false);

		}

		kfree(fake_devname);

		kfree(cifs_sb->mountdata);
@@ -3810,11 +3818,11 @@ expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses, 


static int

cifs_setup_volume_info(struct smb_vol *volume_info, char *mount_data,

			const char *devname)

			const char *devname, bool is_smb3)

{

	int rc = 0;



	if (cifs_parse_mount_options(mount_data, devname, volume_info))

	if (cifs_parse_mount_options(mount_data, devname, volume_info, is_smb3))

		return -EINVAL;



	if (volume_info->nullauth) {
@@ -3848,7 +3856,7 @@ cifs_setup_volume_info(struct smb_vol *volume_info, char *mount_data, 
}



struct smb_vol *

cifs_get_volume_info(char *mount_data, const char *devname)

cifs_get_volume_info(char *mount_data, const char *devname, bool is_smb3)

{

	int rc;

	struct smb_vol *volume_info;
@@ -3857,7 +3865,7 @@ cifs_get_volume_info(char *mount_data, const char *devname) 
	if (!volume_info)

		return ERR_PTR(-ENOMEM);



	rc = cifs_setup_volume_info(volume_info, mount_data, devname);

	rc = cifs_setup_volume_info(volume_info, mount_data, devname, is_smb3);

	if (rc) {

		cifs_cleanup_volume_info(volume_info);

		volume_info = ERR_PTR(rc);