cifs: we do not allow changing username/password/unc/... during remount

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 6a3cb19..276b065 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -493,7 +493,7 @@ cifs_show_options(struct seq_file *s, struct dentry *root)
 
        if (tcon->no_lease)
                seq_puts(s, ",nolease");
-       if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER)
+       if (cifs_sb->ctx->multiuser)
                seq_puts(s, ",multiuser");
        else if (tcon->ses->user_name)
                seq_show_option(s, "username", tcon->ses->user_name);

diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index 18b469f..b807f8a 100644 (file)
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -632,10 +632,51 @@ static int smb3_verify_reconfigure_ctx(struct smb3_fs_context *new_ctx,
                cifs_dbg(VFS, "can not change sec during remount\n");
                return -EINVAL;
        }
+       if (new_ctx->multiuser != old_ctx->multiuser) {
+               cifs_dbg(VFS, "can not change multiuser during remount\n");
+               return -EINVAL;
+       }
+       if (new_ctx->UNC &&
+           (!old_ctx->UNC || strcmp(new_ctx->UNC, old_ctx->UNC))) {
+               cifs_dbg(VFS, "can not change UNC during remount\n");
+               return -EINVAL;
+       }
+       if (new_ctx->username &&
+           (!old_ctx->username || strcmp(new_ctx->username, old_ctx->username))) {
+               cifs_dbg(VFS, "can not change username during remount\n");
+               return -EINVAL;
+       }
+       if (new_ctx->password &&
+           (!old_ctx->password || strcmp(new_ctx->password, old_ctx->password))) {
+               cifs_dbg(VFS, "can not change password during remount\n");
+               return -EINVAL;
+       }
+       if (new_ctx->domainname &&
+           (!old_ctx->domainname || strcmp(new_ctx->domainname, old_ctx->domainname))) {
+               cifs_dbg(VFS, "can not change domainname during remount\n");
+               return -EINVAL;
+       }
+       if (new_ctx->nodename &&
+           (!old_ctx->nodename || strcmp(new_ctx->nodename, old_ctx->nodename))) {
+               cifs_dbg(VFS, "can not change nodename during remount\n");
+               return -EINVAL;
+       }
+       if (new_ctx->iocharset &&
+           (!old_ctx->iocharset || strcmp(new_ctx->iocharset, old_ctx->iocharset))) {
+               cifs_dbg(VFS, "can not change iocharset during remount\n");
+               return -EINVAL;
+       }
 
        return 0;
 }
 
+#define STEAL_STRING(cifs_sb, ctx, field)                              \
+do {                                                                   \
+       kfree(ctx->field);                                              \
+       ctx->field = cifs_sb->ctx->field;                               \
+       cifs_sb->ctx->field = NULL;                                     \
+} while (0)
+
 static int smb3_reconfigure(struct fs_context *fc)
 {
        struct smb3_fs_context *ctx = smb3_fc2context(fc);
@@ -648,10 +689,16 @@ static int smb3_reconfigure(struct fs_context *fc)
                return rc;
 
        /*
-        * Steal the UNC from the old and to be destroyed context.
+        * We can not change UNC/username/password/domainname/nodename/iocharset
+        * during reconnect so ignore what we have in the new context and
+        * just use what we already have in cifs_sb->ctx.
         */
-       ctx->UNC = cifs_sb->ctx->UNC;
-       cifs_sb->ctx->UNC = NULL;
+       STEAL_STRING(cifs_sb, ctx, UNC);
+       STEAL_STRING(cifs_sb, ctx, username);
+       STEAL_STRING(cifs_sb, ctx, password);
+       STEAL_STRING(cifs_sb, ctx, domainname);
+       STEAL_STRING(cifs_sb, ctx, nodename);
+       STEAL_STRING(cifs_sb, ctx, iocharset);
 
        smb3_cleanup_fs_context_contents(cifs_sb->ctx);
        rc = smb3_fs_context_dup(cifs_sb->ctx, ctx);

diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
index 7c794df..1680d0c 100644 (file)
--- a/fs/cifs/fs_context.h
+++ b/fs/cifs/fs_context.h
@@ -149,7 +149,6 @@ struct smb3_fs_context {
        bool uid_specified;
        bool gid_specified;
        bool sloppy;
-       char *nodename;
        bool got_ip;
        bool got_version;
        bool got_rsize;
@@ -161,6 +160,7 @@ struct smb3_fs_context {
        char *password;
        char *domainname;
        char *UNC;
+       char *nodename;
        char *iocharset;  /* local code page for mapping to and from Unicode */
        char source_rfc1001_name[RFC1001_NAME_LEN_WITH_NULL]; /* clnt nb name */
        char target_rfc1001_name[RFC1001_NAME_LEN_WITH_NULL]; /* srvr nb name */