diff options
| -rw-r--r-- | fs/namespace.c | 65 |
1 files changed, 39 insertions, 26 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 0354cb6ac2d3..f629e1c7f3cc 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2523,7 +2523,37 @@ unlock: return err; } -static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags); +static bool mount_too_revealing(const struct super_block *sb, int *new_mnt_flags); + +/* + * Create a new mount using a superblock configuration and request it + * be added to the namespace tree. + */ +static int do_new_mount_fc(struct fs_context *fc, struct path *mountpoint, + unsigned int mnt_flags) +{ + struct vfsmount *mnt; + struct super_block *sb = fc->root->d_sb; + int error; + + if (mount_too_revealing(sb, &mnt_flags)) { + dput(fc->root); + fc->root = NULL; + deactivate_locked_super(sb); + return -EPERM; + } + + up_write(&sb->s_umount); + + mnt = vfs_create_mount(fc); + if (IS_ERR(mnt)) + return PTR_ERR(mnt); + + error = do_add_mount(real_mount(mnt), mountpoint, mnt_flags); + if (error < 0) + mntput(mnt); + return error; +} /* * create a new mount for userspace and request it to be added into the @@ -2533,7 +2563,6 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags, int mnt_flags, const char *name, void *data) { struct file_system_type *type; - struct vfsmount *mnt; struct fs_context *fc; const char *subtype = NULL; int err = 0; @@ -2577,26 +2606,9 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags, err = parse_monolithic_mount_data(fc, data); if (!err) err = vfs_get_tree(fc); - if (err) - goto out; - - up_write(&fc->root->d_sb->s_umount); - mnt = vfs_create_mount(fc); - if (IS_ERR(mnt)) { - err = PTR_ERR(mnt); - goto out; - } - - if (mount_too_revealing(mnt, &mnt_flags)) { - mntput(mnt); - err = -EPERM; - goto out; - } + if (!err) + err = do_new_mount_fc(fc, path, mnt_flags); - err = do_add_mount(real_mount(mnt), path, mnt_flags); - if (err) - mntput(mnt); -out: put_fs_context(fc); return err; } @@ -3421,7 +3433,8 @@ bool current_chrooted(void) return chrooted; } -static bool mnt_already_visible(struct mnt_namespace *ns, struct vfsmount *new, +static bool mnt_already_visible(struct mnt_namespace *ns, + const struct super_block *sb, int *new_mnt_flags) { int new_flags = *new_mnt_flags; @@ -3433,7 +3446,7 @@ static bool mnt_already_visible(struct mnt_namespace *ns, struct vfsmount *new, struct mount *child; int mnt_flags; - if (mnt->mnt.mnt_sb->s_type != new->mnt_sb->s_type) + if (mnt->mnt.mnt_sb->s_type != sb->s_type) continue; /* This mount is not fully visible if it's root directory @@ -3484,7 +3497,7 @@ found: return visible; } -static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags) +static bool mount_too_revealing(const struct super_block *sb, int *new_mnt_flags) { const unsigned long required_iflags = SB_I_NOEXEC | SB_I_NODEV; struct mnt_namespace *ns = current->nsproxy->mnt_ns; @@ -3494,7 +3507,7 @@ static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags) return false; /* Can this filesystem be too revealing? */ - s_iflags = mnt->mnt_sb->s_iflags; + s_iflags = sb->s_iflags; if (!(s_iflags & SB_I_USERNS_VISIBLE)) return false; @@ -3504,7 +3517,7 @@ static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags) return true; } - return !mnt_already_visible(ns, mnt, new_mnt_flags); + return !mnt_already_visible(ns, sb, new_mnt_flags); } bool mnt_may_suid(struct vfsmount *mnt) |