diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/9p/acl.c | 2 | ||||
| -rw-r--r-- | fs/attr.c | 19 | ||||
| -rw-r--r-- | fs/block_dev.c | 2 | ||||
| -rw-r--r-- | fs/devpts/inode.c | 3 | ||||
| -rw-r--r-- | fs/exec.c | 2 | ||||
| -rw-r--r-- | fs/inode.c | 7 | ||||
| -rw-r--r-- | fs/kernfs/mount.c | 5 | ||||
| -rw-r--r-- | fs/namei.c | 55 | ||||
| -rw-r--r-- | fs/namespace.c | 99 | ||||
| -rw-r--r-- | fs/nfsd/nfsctl.c | 13 | ||||
| -rw-r--r-- | fs/posix_acl.c | 8 | ||||
| -rw-r--r-- | fs/proc/inode.c | 15 | ||||
| -rw-r--r-- | fs/proc/internal.h | 3 | ||||
| -rw-r--r-- | fs/proc/root.c | 61 | ||||
| -rw-r--r-- | fs/quota/dquot.c | 8 | ||||
| -rw-r--r-- | fs/quota/quota.c | 14 | ||||
| -rw-r--r-- | fs/super.c | 69 | ||||
| -rw-r--r-- | fs/sysfs/mount.c | 5 | ||||
| -rw-r--r-- | fs/xattr.c | 7 |
19 files changed, 242 insertions, 155 deletions
diff --git a/fs/9p/acl.c b/fs/9p/acl.c index 0576eaeb60b9..5b6a1743ea17 100644 --- a/fs/9p/acl.c +++ b/fs/9p/acl.c @@ -266,7 +266,7 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler, if (IS_ERR(acl)) return PTR_ERR(acl); else if (acl) { - retval = posix_acl_valid(acl); + retval = posix_acl_valid(inode->i_sb->s_user_ns, acl); if (retval) goto err_out; } diff --git a/fs/attr.c b/fs/attr.c index 25b24d0f6c88..42bb42bb3c72 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -255,6 +255,25 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID))) return 0; + /* + * Verify that uid/gid changes are valid in the target + * namespace of the superblock. + */ + if (ia_valid & ATTR_UID && + !kuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid)) + return -EOVERFLOW; + if (ia_valid & ATTR_GID && + !kgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid)) + return -EOVERFLOW; + + /* Don't allow modifications of files with invalid uids or + * gids unless those uids & gids are being made valid. + */ + if (!(ia_valid & ATTR_UID) && !uid_valid(inode->i_uid)) + return -EOVERFLOW; + if (!(ia_valid & ATTR_GID) && !gid_valid(inode->i_gid)) + return -EOVERFLOW; + error = security_inode_setattr(dentry, attr); if (error) return error; diff --git a/fs/block_dev.c b/fs/block_dev.c index 5cbd5391667e..ada42cf42d06 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1846,7 +1846,7 @@ struct block_device *lookup_bdev(const char *pathname) if (!S_ISBLK(inode->i_mode)) goto fail; error = -EACCES; - if (path.mnt->mnt_flags & MNT_NODEV) + if (!may_open_dev(&path)) goto fail; error = -ENOMEM; bdev = bd_acquire(inode); diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c index 37c134a132c7..d116453b0276 100644 --- a/fs/devpts/inode.c +++ b/fs/devpts/inode.c @@ -396,6 +396,7 @@ devpts_fill_super(struct super_block *s, void *data, int silent) { struct inode *inode; + s->s_iflags &= ~SB_I_NODEV; s->s_blocksize = 1024; s->s_blocksize_bits = 10; s->s_magic = DEVPTS_SUPER_MAGIC; @@ -480,7 +481,7 @@ static struct file_system_type devpts_fs_type = { .name = "devpts", .mount = devpts_mount, .kill_sb = devpts_kill_sb, - .fs_flags = FS_USERNS_MOUNT | FS_USERNS_DEV_MOUNT, + .fs_flags = FS_USERNS_MOUNT, }; /* diff --git a/fs/exec.c b/fs/exec.c index 887c1c955df8..ca239fc86d8d 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1411,7 +1411,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm) bprm->cred->euid = current_euid(); bprm->cred->egid = current_egid(); - if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) + if (!mnt_may_suid(bprm->file->f_path.mnt)) return; if (task_no_new_privs(current)) diff --git a/fs/inode.c b/fs/inode.c index e171f7b5f9e4..9cef4e16aeda 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1619,6 +1619,13 @@ bool atime_needs_update(const struct path *path, struct inode *inode) if (inode->i_flags & S_NOATIME) return false; + + /* Atime updates will likely cause i_uid and i_gid to be written + * back improprely if their true value is unknown to the vfs. + */ + if (HAS_UNMAPPED_ID(inode)) + return false; + if (IS_NOATIME(inode)) return false; if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index 63534f5f9073..b3d73ad52b22 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -152,6 +152,8 @@ static int kernfs_fill_super(struct super_block *sb, unsigned long magic) struct dentry *root; info->sb = sb; + /* Userspace would break if executables or devices appear on sysfs */ + sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV; sb->s_blocksize = PAGE_SIZE; sb->s_blocksize_bits = PAGE_SHIFT; sb->s_magic = magic; @@ -241,7 +243,8 @@ struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags, info->root = root; info->ns = ns; - sb = sget(fs_type, kernfs_test_super, kernfs_set_super, flags, info); + sb = sget_userns(fs_type, kernfs_test_super, kernfs_set_super, flags, + &init_user_ns, info); if (IS_ERR(sb) || sb->s_fs_info != info) kfree(info); if (IS_ERR(sb)) diff --git a/fs/namei.c b/fs/namei.c index 68a896c804b7..c386a329ab20 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -36,6 +36,7 @@ #include <linux/posix_acl.h> #include <linux/hash.h> #include <linux/bitops.h> +#include <linux/init_task.h> #include <asm/uaccess.h> #include "internal.h" @@ -410,6 +411,14 @@ int __inode_permission(struct inode *inode, int mask) */ if (IS_IMMUTABLE(inode)) return -EACCES; + + /* + * Updating mtime will likely cause i_uid and i_gid to be + * written back improperly if their true value is unknown + * to the vfs. + */ + if (HAS_UNMAPPED_ID(inode)) + return -EACCES; } retval = do_inode_permission(inode, mask); @@ -901,6 +910,7 @@ static inline int may_follow_link(struct nameidata *nd) { const struct inode *inode; const struct inode *parent; + kuid_t puid; if (!sysctl_protected_symlinks) return 0; @@ -916,7 +926,8 @@ static inline int may_follow_link(struct nameidata *nd) return 0; /* Allowed if parent directory and link owner match. */ - if (uid_eq(parent->i_uid, inode->i_uid)) + puid = parent->i_uid; + if (uid_valid(puid) && uid_eq(puid, inode->i_uid)) return 0; if (nd->flags & LOOKUP_RCU) @@ -1089,6 +1100,7 @@ static int follow_automount(struct path *path, struct nameidata *nd, bool *need_mntput) { struct vfsmount *mnt; + const struct cred *old_cred; int err; if (!path->dentry->d_op || !path->dentry->d_op->d_automount) @@ -1110,11 +1122,16 @@ static int follow_automount(struct path *path, struct nameidata *nd, path->dentry->d_inode) return -EISDIR; + if (path->dentry->d_sb->s_user_ns != &init_user_ns) + return -EACCES; + nd->total_link_count++; if (nd->total_link_count >= 40) return -ELOOP; + old_cred = override_creds(&init_cred); mnt = path->dentry->d_op->d_automount(path); + revert_creds(old_cred); if (IS_ERR(mnt)) { /* * The filesystem is allowed to return -EISDIR here to indicate @@ -2741,10 +2758,11 @@ EXPORT_SYMBOL(__check_sticky); * c. have CAP_FOWNER capability * 6. If the victim is append-only or immutable we can't do antyhing with * links pointing to it. - * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. - * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. - * 9. We can't remove a root or mountpoint. - * 10. We don't allow removal of NFS sillyrenamed files; it's handled by + * 7. If the victim has an unknown uid or gid we can't change the inode. + * 8. If we were asked to remove a directory and victim isn't one - ENOTDIR. + * 9. If we were asked to remove a non-directory and victim isn't one - EISDIR. + * 10. We can't remove a root or mountpoint. + * 11. We don't allow removal of NFS sillyrenamed files; it's handled by * nfs_async_unlink(). */ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) @@ -2766,7 +2784,7 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) return -EPERM; if (check_sticky(dir, inode) || IS_APPEND(inode) || - IS_IMMUTABLE(inode) || IS_SWAPFILE(inode)) + IS_IMMUTABLE(inode) || IS_SWAPFILE(inode) || HAS_UNMAPPED_ID(inode)) return -EPERM; if (isdir) { if (!d_is_dir(victim)) @@ -2787,16 +2805,22 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) * 1. We can't do it if child already exists (open has special treatment for * this case, but since we are inlined it's OK) * 2. We can't do it if dir is read-only (done in permission()) - * 3. We should have write and exec permissions on dir - * 4. We can't do it if dir is immutable (done in permission()) + * 3. We can't do it if the fs can't represent the fsuid or fsgid. + * 4. We should have write and exec permissions on dir + * 5. We can't do it if dir is immutable (done in permission()) */ static inline int may_create(struct inode *dir, struct dentry *child) { + struct user_namespace *s_user_ns; audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE); if (child->d_inode) return -EEXIST; if (IS_DEADDIR(dir)) return -ENOENT; + s_user_ns = dir->i_sb->s_user_ns; + if (!kuid_has_mapping(s_user_ns, current_fsuid()) || + !kgid_has_mapping(s_user_ns, current_fsgid())) + return -EOVERFLOW; return inode_permission(dir, MAY_WRITE | MAY_EXEC); } @@ -2865,6 +2889,12 @@ int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, } EXPORT_SYMBOL(vfs_create); +bool may_open_dev(const struct path *path) +{ + return !(path->mnt->mnt_flags & MNT_NODEV) && + !(path->mnt->mnt_sb->s_iflags & SB_I_NODEV); +} + static int may_open(struct path *path, int acc_mode, int flag) { struct dentry *dentry = path->dentry; @@ -2883,7 +2913,7 @@ static int may_open(struct path *path, int acc_mode, int flag) break; case S_IFBLK: case S_IFCHR: - if (path->mnt->mnt_flags & MNT_NODEV) + if (!may_open_dev(path)) return -EACCES; /*FALLTHRU*/ case S_IFIFO: @@ -4135,6 +4165,13 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de */ if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) return -EPERM; + /* + * Updating the link count will likely cause i_uid and i_gid to + * be writen back improperly if their true value is unknown to + * the vfs. + */ + if (HAS_UNMAPPED_ID(inode)) + return -EPERM; if (!dir->i_op->link) return -EPERM; if (S_ISDIR(inode->i_mode)) diff --git a/fs/namespace.c b/fs/namespace.c index 419f746d851d..7bb2cda3bfef 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2186,13 +2186,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags, } if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) && !(mnt_flags & MNT_NODEV)) { - /* Was the nodev implicitly added in mount? */ - if ((mnt->mnt_ns->user_ns != &init_user_ns) && - !(sb->s_type->fs_flags & FS_USERNS_DEV_MOUNT)) { - mnt_flags |= MNT_NODEV; - } else { - return -EPERM; - } + return -EPERM; } if ((mnt->mnt.mnt_flags & MNT_LOCK_NOSUID) && !(mnt_flags & MNT_NOSUID)) { @@ -2376,7 +2370,7 @@ unlock: return err; } -static bool fs_fully_visible(struct file_system_type *fs_type, int *new_mnt_flags); +static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags); /* * create a new mount for userspace and request it to be added into the @@ -2386,7 +2380,6 @@ static int do_new_mount(struct path *path, const char *fstype, int flags, int mnt_flags, const char *name, void *data) { struct file_system_type *type; - struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns; struct vfsmount *mnt; int err; @@ -2397,26 +2390,6 @@ static int do_new_mount(struct path *path, const char *fstype, int flags, if (!type) return -ENODEV; - if (user_ns != &init_user_ns) { - if (!(type->fs_flags & FS_USERNS_MOUNT)) { - put_filesystem(type); - return -EPERM; - } - /* Only in special cases allow devices from mounts - * created outside the initial user namespace. - */ - if (!(type->fs_flags & FS_USERNS_DEV_MOUNT)) { - flags |= MS_NODEV; - mnt_flags |= MNT_NODEV | MNT_LOCK_NODEV; - } - if (type->fs_flags & FS_USERNS_VISIBLE) { - if (!fs_fully_visible(type, &mnt_flags)) { - put_filesystem(type); - return -EPERM; - } - } - } - mnt = vfs_kern_mount(type, flags, name, data); if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && !mnt->mnt_sb->s_subtype) @@ -2426,6 +2399,11 @@ static int do_new_mount(struct path *path, const char *fstype, int flags, if (IS_ERR(mnt)) return PTR_ERR(mnt); + if (mount_too_revealing(mnt, &mnt_flags)) { + mntput(mnt); + return -EPERM; + } + err = do_add_mount(real_mount(mnt), path, mnt_flags); if (err) mntput(mnt); @@ -3217,22 +3195,19 @@ bool current_chrooted(void) return chrooted; } -static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags) +static bool mnt_already_visible(struct mnt_namespace *ns, struct vfsmount *new, + int *new_mnt_flags) { - struct mnt_namespace *ns = current->nsproxy->mnt_ns; int new_flags = *new_mnt_flags; struct mount *mnt; bool visible = false; - if (unlikely(!ns)) - return false; - down_read(&namespace_sem); list_for_each_entry(mnt, &ns->list, mnt_list) { struct mount *child; int mnt_flags; - if (mnt->mnt.mnt_sb->s_type != type) + if (mnt->mnt.mnt_sb->s_type != new->mnt_sb->s_type) continue; /* This mount is not fully visible if it's root directory @@ -3241,12 +3216,8 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags) if (mnt->mnt.mnt_root != mnt->mnt.mnt_sb->s_root) continue; - /* Read the mount flags and filter out flags that - * may safely be ignored. - */ + /* A local view of the mount flags */ mnt_flags = mnt->mnt.mnt_flags; - if (mnt->mnt.mnt_sb->s_iflags & SB_I_NOEXEC) - mnt_flags &= ~(MNT_LOCK_NOSUID | MNT_LOCK_NOEXEC); /* Don't miss readonly hidden in the superblock flags */ if (mnt->mnt.mnt_sb->s_flags & MS_RDONLY) @@ -3258,15 +3229,6 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags) if ((mnt_flags & MNT_LOCK_READONLY) && !(new_flags & MNT_READONLY)) continue; - if ((mnt_flags & MNT_LOCK_NODEV) && - !(new_flags & MNT_NODEV)) - continue; - if ((mnt_flags & MNT_LOCK_NOSUID) && - !(new_flags & MNT_NOSUID)) - continue; - if ((mnt_flags & MNT_LOCK_NOEXEC) && - !(new_flags & MNT_NOEXEC)) - continue; if ((mnt_flags & MNT_LOCK_ATIME) && ((mnt_flags & MNT_ATIME_MASK) != (new_flags & MNT_ATIME_MASK))) continue; @@ -3286,9 +3248,6 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags) } /* Preserve the locked attributes */ *new_mnt_flags |= mnt_flags & (MNT_LOCK_READONLY | \ - MNT_LOCK_NODEV | \ - MNT_LOCK_NOSUID | \ - MNT_LOCK_NOEXEC | \ MNT_LOCK_ATIME); visible = true; goto found; @@ -3299,6 +3258,42 @@ found: return visible; } +static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags) +{ + const unsigned long required_iflags = SB_I_NOEXEC | SB_I_NODEV; + struct mnt_namespace *ns = current->nsproxy->mnt_ns; + unsigned long s_iflags; + + if (ns->user_ns == &init_user_ns) + return false; + + /* Can this filesystem be too revealing? */ + s_iflags = mnt->mnt_sb->s_iflags; + if (!(s_iflags & SB_I_USERNS_VISIBLE)) + return false; + + if ((s_iflags & required_iflags) != required_iflags) { + WARN_ONCE(1, "Expected s_iflags to contain 0x%lx\n", + required_iflags); + return true; + } + + return !mnt_already_visible(ns, mnt, new_mnt_flags); +} + +bool mnt_may_suid(struct vfsmount *mnt) +{ + /* + * Foreign mounts (accessed via fchdir or through /proc + * symlinks) are always treated as if they are nosuid. This + * prevents namespaces from trusting potentially unsafe + * suid/sgid bits, file caps, or security labels that originate + * in other namespaces. + */ + return !(mnt->mnt_flags & MNT_NOSUID) && check_mnt(real_mount(mnt)) && + current_in_userns(mnt->mnt_sb->s_user_ns); +} + static struct ns_common *mntns_get(struct task_struct *task) { struct ns_common *ns = NULL; diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index e7787777620e..65ad0165a94f 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -1151,20 +1151,15 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent) #endif /* last one */ {""} }; - struct net *net = data; - int ret; - - ret = simple_fill_super(sb, 0x6e667364, nfsd_files); - if (ret) - return ret; - sb->s_fs_info = get_net(net); - return 0; + get_net(sb->s_fs_info); + return simple_fill_super(sb, 0x6e667364, nfsd_files); } static struct dentry *nfsd_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { - return mount_ns(fs_type, flags, current->nsproxy->net_ns, nfsd_fill_super); + struct net *net = current->nsproxy->net_ns; + return mount_ns(fs_type, flags, data, net, net->user_ns, nfsd_fill_super); } static void nfsd_umount(struct super_block *sb) diff --git a/fs/posix_acl.c b/fs/posix_acl.c index edc452c2a563..59d47ab0791a 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -205,7 +205,7 @@ posix_acl_clone(const struct posix_acl *acl, gfp_t flags) * Check if an acl is valid. Returns 0 if it is, or -E... otherwise. */ int -posix_acl_valid(const struct posix_acl *acl) +posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl) { const struct posix_acl_entry *pa, *pe; int state = ACL_USER_OBJ; @@ -225,7 +225,7 @@ posix_acl_valid(const struct posix_acl *acl) case ACL_USER: if (state != ACL_USER) return -EINVAL; - if (!uid_valid(pa->e_uid)) + if (!kuid_has_mapping(user_ns, pa->e_uid)) return -EINVAL; needs_mask = 1; break; @@ -240,7 +240,7 @@ posix_acl_valid(const struct posix_acl *acl) case ACL_GROUP: if (state != ACL_GROUP) return -EINVAL; - if (!gid_valid(pa->e_gid)) + if (!kgid_has_mapping(user_ns, pa->e_gid)) return -EINVAL; needs_mask = 1; break; @@ -834,7 +834,7 @@ set_posix_acl(struct inode *inode, int type, struct posix_acl *acl) return -EPERM; if (acl) { - int ret = posix_acl_valid(acl); + int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl); if (ret) return ret; } diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 42305ddcbaa0..c1b72388e571 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -457,17 +457,30 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) return inode; } -int proc_fill_super(struct super_block *s) +int proc_fill_super(struct super_block *s, void *data, int silent) { + struct pid_namespace *ns = get_pid_ns(s->s_fs_info); struct inode *root_inode; int ret; + if (!proc_parse_options(data, ns)) + return -EINVAL; + + /* User space would break if executables or devices appear on proc */ + s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV; s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; s->s_blocksize = 1024; s->s_blocksize_bits = 10; s->s_magic = PROC_SUPER_MAGIC; s->s_op = &proc_sops; s->s_time_gran = 1; + + /* + * procfs isn't actually a stacking filesystem; however, there is + * too much magic going on inside it to permit stacking things on + * top of it + */ + s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; pde_get(&proc_root); root_inode = proc_get_inode(s, &proc_root); diff --git a/fs/proc/internal.h b/fs/proc/internal.h index aa2781095bd1..7931c558c192 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -212,7 +212,7 @@ extern const struct inode_operations proc_pid_link_inode_operations; extern void proc_init_inodecache(void); extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *); -extern int proc_fill_super(struct super_block *); +extern int proc_fill_super(struct super_block *, void *data, int flags); extern void proc_entry_rundown(struct proc_dir_entry *); /* @@ -268,6 +268,7 @@ static inline void proc_tty_init(void) {} * root.c */ extern struct proc_dir_entry proc_root; +extern int proc_parse_options(char *options, struct pid_namespace *pid); extern void proc_self_init(void); extern int proc_remount(struct super_block *, int *, char *); diff --git a/fs/proc/root.c b/fs/proc/root.c index 06702783bf40..8d3e484055a6 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -23,21 +23,6 @@ #include "internal.h" -static int proc_test_super(struct super_block *sb, void *data) -{ - return sb->s_fs_info == data; -} - -static int proc_set_super(struct super_block *sb, void *data) -{ - int err = set_anon_super(sb, NULL); - if (!err) { - struct pid_namespace *ns = (struct pid_namespace *)data; - sb->s_fs_info = get_pid_ns(ns); - } - return err; -} - enum { Opt_gid, Opt_hidepid, Opt_err, }; @@ -48,7 +33,7 @@ static const match_table_t tokens = { {Opt_err, NULL}, }; -static int proc_parse_options(char *options, struct pid_namespace *pid) +int proc_parse_options(char *options, struct pid_namespace *pid) { char *p; substring_t args[MAX_OPT_ARGS]; @@ -100,52 +85,16 @@ int proc_remount(struct super_block *sb, int *flags, char *data) static struct dentry *proc_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { - int err; - struct super_block *sb; struct pid_namespace *ns; - char *options; if (flags & MS_KERNMOUNT) { - ns = (struct pid_namespace *)data; - options = NULL; + ns = data; + data = NULL; } else { ns = task_active_pid_ns(current); - options = data; - - /* Does the mounter have privilege over the pid namespace? */ - if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) - return ERR_PTR(-EPERM); - } - - sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns); - if (IS_ERR(sb)) - return ERR_CAST(sb); - - /* - * procfs isn't actually a stacking filesystem; however, there is - * too much magic going on inside it to permit stacking things on - * top of it - */ - sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; - - if (!proc_parse_options(options, ns)) { - deactivate_locked_super(sb); - return ERR_PTR(-EINVAL); - } - - if (!sb->s_root) { - err = proc_fill_super(sb); - if (err) { - deactivate_locked_super(sb); - return ERR_PTR(err); - } - - sb->s_flags |= MS_ACTIVE; - /* User space would break if executables appear on proc */ - sb->s_iflags |= SB_I_NOEXEC; } - return dget(sb->s_root); + return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super); } static void proc_kill_sb(struct super_block *sb) @@ -165,7 +114,7 @@ static struct file_system_type proc_fs_type = { .name = "proc", .mount = proc_mount, .kill_sb = proc_kill_sb, - .fs_flags = FS_USERNS_VISIBLE | FS_USERNS_MOUNT, + .fs_flags = FS_USERNS_MOUNT, }; void __init proc_root_init(void) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index b1322dd9d136..1bfac28b7e7d 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -841,6 +841,9 @@ struct dquot *dqget(struct super_block *sb, struct kqid qid) unsigned int hashent = hashfn(sb, qid); struct dquot *dquot, *empty = NULL; + if (!qid_has_mapping(sb->s_user_ns, qid)) + return ERR_PTR(-EINVAL); + if (!sb_has_quota_active(sb, qid.type)) return ERR_PTR(-ESRCH); we_slept: @@ -2268,6 +2271,11 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id, error = -EINVAL; goto out_fmt; } + /* Filesystems outside of init_user_ns not yet supported */ + if (sb->s_user_ns != &init_user_ns) { + error = -EINVAL; + goto out_fmt; + } /* Usage always has to be set... */ if (!(flags & DQUOT_USAGE_ENABLED)) { error = -EINVAL; diff --git a/fs/quota/quota.c b/fs/quota/quota.c index 0f10ee9892ce..35df08ee9c97 100644 --- a/fs/quota/quota.c +++ b/fs/quota/quota.c @@ -211,7 +211,7 @@ static int quota_getquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->get_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; ret = sb->s_qcop->get_dqblk(sb, qid, &fdq); if (ret) @@ -237,7 +237,7 @@ static int quota_getnextquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->get_nextdqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; ret = sb->s_qcop->get_nextdqblk(sb, &qid, &fdq); if (ret) @@ -288,7 +288,7 @@ static int quota_setquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->set_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; copy_from_if_dqblk(&fdq, &idq); return sb->s_qcop->set_dqblk(sb, qid, &fdq); @@ -581,10 +581,10 @@ static int quota_setxquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->set_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; /* Are we actually setting timer / warning limits for all users? */ - if (from_kqid(&init_user_ns, qid) == 0 && + if (from_kqid(sb->s_user_ns, qid) == 0 && fdq.d_fieldmask & (FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK)) { struct qc_info qinfo; int ret; @@ -642,7 +642,7 @@ static int quota_getxquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->get_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; ret = sb->s_qcop->get_dqblk(sb, qid, &qdq); if (ret) @@ -669,7 +669,7 @@ static int quota_getnextxquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->get_nextdqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; ret = sb->s_qcop->get_nextdqblk(sb, &qid, &qdq); if (ret) diff --git a/fs/super.c b/fs/super.c index 5806ffd45563..c2ff475c1711 100644 --- a/fs/super.c +++ b/fs/super.c @@ -33,6 +33,7 @@ #include <linux/cleancache.h> #include <linux/fsnotify.h> #include <linux/lockdep.h> +#include <linux/user_namespace.h> #include "internal.h" @@ -165,6 +166,7 @@ static void destroy_super(struct super_block *s) list_lru_destroy(&s->s_inode_lru); security_sb_free(s); WARN_ON(!list_empty(&s->s_mounts)); + put_user_ns(s->s_user_ns); kfree(s->s_subtype); kfree(s->s_options); call_rcu(&s->rcu, destroy_super_rcu); @@ -174,11 +176,13 @@ static void destroy_super(struct super_block *s) * alloc_super - create new superblock * @type: filesystem type superblock should belong to * @flags: the mount flags + * @user_ns: User namespace for the super_block * * Allocates and initializes a new &struct super_block. alloc_super() * returns a pointer new superblock or %NULL if allocation had failed. */ -static struct super_block *alloc_super(struct file_system_type *type, int flags) +static struct super_block *alloc_super(struct file_system_type *type, int flags, + struct user_namespace *user_ns) { struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER); static const struct super_operations default_op; @@ -188,6 +192,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags) return NULL; INIT_LIST_HEAD(&s->s_mounts); + s->s_user_ns = get_user_ns(user_ns); if (security_sb_alloc(s)) goto fail; @@ -201,6 +206,8 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags) init_waitqueue_head(&s->s_writers.wait_unfrozen); s->s_bdi = &noop_backing_dev_info; s->s_flags = flags; + if (s->s_user_ns != &init_user_ns) + s->s_iflags |= SB_I_NODEV; INIT_HLIST_NODE(&s->s_instances); INIT_HLIST_BL_HEAD(&s->s_anon); mutex_init(&s->s_sync_lock); @@ -445,29 +452,42 @@ void generic_shutdown_super(struct super_block *sb) EXPORT_SYMBOL(generic_shutdown_super); /** - * sget - find or create a superblock + * sget_userns - find or create a superblock * @type: filesystem type superblock should belong to * @test: comparison callback * @set: setup callback * @flags: mount flags + * @user_ns: User namespace for the super_block * @data: argument to each of them */ -struct super_block *sget(struct file_system_type *type, +struct super_block *sget_userns(struct file_system_type *type, int (*test)(struct super_block *,void *), int (*set)(struct super_block *,void *), - int flags, + int flags, struct user_namespace *user_ns, void *data) { struct super_block *s = NULL; struct super_block *old; int err; + if (!(flags & MS_KERNMOUNT) && + !(type->fs_flags & FS_USERNS_MOUNT) && + !capable(CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); retry: spin_lock(&sb_lock); if (test) { hlist_for_each_entry(old, &type->fs_supers, s_instances) { if (!test(old, data)) continue; + if (user_ns != old->s_user_ns) { + spin_unlock(&sb_lock); + if (s) { + up_write(&s->s_umount); + destroy_super(s); + } + return ERR_PTR(-EBUSY); + } if (!grab_super(old)) goto retry; if (s) { @@ -480,7 +500,7 @@ retry: } if (!s) { spin_unlock(&sb_lock); - s = alloc_super(type, flags); + s = alloc_super(type, flags, user_ns); if (!s) return ERR_PTR(-ENOMEM); goto retry; @@ -503,6 +523,31 @@ retry: return s; } +EXPORT_SYMBOL(sget_userns); + +/** + * sget - find or create a superblock + * @type: filesystem type superblock should belong to + * @test: comparison callback + * @set: setup callback + * @flags: mount flags + * @data: argument to each of them + */ +struct super_block *sget(struct file_system_type *type, + int (*test)(struct super_block *,void *), + int (*set)(struct super_block *,void *), + int flags, + void *data) +{ + struct user_namespace *user_ns = current_user_ns(); + + /* Ensure the requestor has permissions over the target filesystem */ + if (!(flags & MS_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + + return sget_userns(type, test, set, flags, user_ns, data); +} + EXPORT_SYMBOL(sget); void drop_super(struct super_block *sb) @@ -920,12 +965,20 @@ static int ns_set_super(struct super_block *sb, void *data) return set_anon_super(sb, NULL); } -struct dentry *mount_ns(struct file_system_type *fs_type, int flags, - void *data, int (*fill_super)(struct super_block *, void *, int)) +struct dentry *mount_ns(struct file_system_type *fs_type, + int flags, void *data, void *ns, struct user_namespace *user_ns, + int (*fill_super)(struct super_block *, void *, int)) { struct super_block *sb; - sb = sget(fs_type, ns_test_super, ns_set_super, flags, data); + /* Don't allow mounting unless the caller has CAP_SYS_ADMIN + * over the namespace. + */ + if (!(flags & MS_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + + sb = sget_userns(fs_type, ns_test_super, ns_set_super, flags, + user_ns, ns); if (IS_ERR(sb)) return ERR_CAST(sb); diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index f3db82071cfb..20b8f82e115b 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -41,8 +41,7 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type, if (IS_ERR(root) || !new_sb) kobj_ns_drop(KOBJ_NS_TYPE_NET, ns); else if (new_sb) - /* Userspace would break if executables appear on sysfs */ - root->d_sb->s_iflags |= SB_I_NOEXEC; + root->d_sb->s_iflags |= SB_I_USERNS_VISIBLE; return root; } @@ -59,7 +58,7 @@ static struct file_system_type sysfs_fs_type = { .name = "sysfs", .mount = sysfs_mount, .kill_sb = sysfs_kill_sb, - .fs_flags = FS_USERNS_VISIBLE | FS_USERNS_MOUNT, + .fs_flags = FS_USERNS_MOUNT, }; int __init sysfs_init(void) diff --git a/fs/xattr.c b/fs/xattr.c index 4beafc43daa5..c243905835ab 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -38,6 +38,13 @@ xattr_permission(struct inode *inode, const char *name, int mask) if (mask & MAY_WRITE) { if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) return -EPERM; + /* + * Updating an xattr will likely cause i_uid and i_gid + * to be writen back improperly if their true value is + * unknown to the vfs. + */ + if (HAS_UNMAPPED_ID(inode)) + return -EPERM; } /* |