lkml.org 
[lkml]   [2008]   [Jan]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [patch 7/9] unprivileged mounts: allow unprivileged fuse mounts
    Quoting Miklos Szeredi (miklos@szeredi.hu):
    > From: Miklos Szeredi <mszeredi@suse.cz>
    >
    > Use FS_SAFE for "fuse" fs type, but not for "fuseblk".
    >
    > FUSE was designed from the beginning to be safe for unprivileged users. This
    > has also been verified in practice over many years. In addition unprivileged
    > mounts require the parent mount to be owned by the user, which is more strict
    > than the current userspace policy.
    >
    > This will enable future installations to remove the suid-root fusermount
    > utility.
    >
    > Don't require the "user_id=" and "group_id=" options for unprivileged mounts,
    > but if they are present, verify them for sanity.
    >
    > Disallow the "allow_other" option for unprivileged mounts.
    >
    > Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

    Sounds like a sysctl to enable FS_SAFE for fuse will make this patch
    acceptable to everyone?

    > ---
    >
    > Index: linux/fs/fuse/inode.c
    > ===================================================================
    > --- linux.orig/fs/fuse/inode.c 2008-01-03 17:13:13.000000000 +0100
    > +++ linux/fs/fuse/inode.c 2008-01-03 21:28:01.000000000 +0100
    > @@ -357,6 +357,19 @@ static int parse_fuse_opt(char *opt, str
    > d->max_read = ~0;
    > d->blksize = 512;
    >
    > + /*
    > + * For unprivileged mounts use current uid/gid. Still allow
    > + * "user_id" and "group_id" options for compatibility, but
    > + * only if they match these values.
    > + */
    > + if (!capable(CAP_SYS_ADMIN)) {
    > + d->user_id = current->uid;
    > + d->user_id_present = 1;
    > + d->group_id = current->gid;
    > + d->group_id_present = 1;
    > +
    > + }
    > +
    > while ((p = strsep(&opt, ",")) != NULL) {
    > int token;
    > int value;
    > @@ -385,6 +398,8 @@ static int parse_fuse_opt(char *opt, str
    > case OPT_USER_ID:
    > if (match_int(&args[0], &value))
    > return 0;
    > + if (d->user_id_present && d->user_id != value)
    > + return 0;
    > d->user_id = value;
    > d->user_id_present = 1;
    > break;
    > @@ -392,6 +407,8 @@ static int parse_fuse_opt(char *opt, str
    > case OPT_GROUP_ID:
    > if (match_int(&args[0], &value))
    > return 0;
    > + if (d->group_id_present && d->group_id != value)
    > + return 0;
    > d->group_id = value;
    > d->group_id_present = 1;
    > break;
    > @@ -596,6 +613,10 @@ static int fuse_fill_super(struct super_
    > if (!parse_fuse_opt((char *) data, &d, is_bdev))
    > return -EINVAL;
    >
    > + /* This is a privileged option */
    > + if ((d.flags & FUSE_ALLOW_OTHER) && !capable(CAP_SYS_ADMIN))
    > + return -EPERM;
    > +
    > if (is_bdev) {
    > #ifdef CONFIG_BLOCK
    > if (!sb_set_blocksize(sb, d.blksize))
    > @@ -696,9 +717,9 @@ static int fuse_get_sb(struct file_syste
    > static struct file_system_type fuse_fs_type = {
    > .owner = THIS_MODULE,
    > .name = "fuse",
    > - .fs_flags = FS_HAS_SUBTYPE,
    > .get_sb = fuse_get_sb,
    > .kill_sb = kill_anon_super,
    > + .fs_flags = FS_HAS_SUBTYPE | FS_SAFE,
    > };
    >
    > #ifdef CONFIG_BLOCK
    >
    > --


    \
     
     \ /
      Last update: 2008-01-15 00:27    [W:0.073 / U:0.012 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site