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: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Sachin Prabhu <sprabhu@redhat.com>

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index eb7b6573f322e430a66ba867080a4625be76bbc0..d5aa7ae917bf1c4d08b4f055bc80051713d94801 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -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 @@ out_nls:
        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 */
 };

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 84765c8764bf63e3ee4bf5fd599f715af6648325..4e0d183c3d1016918d9934420af6e626d128d077 100644 (file)
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -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);

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 9089b73809de3f034dbb62639fa2bd2c79a4c7da..96645a7d8f27144a885863578d33e2b757afeec6 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -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);