diff options
Diffstat (limited to 'fs/overlayfs/util.c')
| -rw-r--r-- | fs/overlayfs/util.c | 395 |
1 files changed, 294 insertions, 101 deletions
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 042f7eb4f7f4..81a57a8d80d9 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -10,6 +10,7 @@ #include <linux/cred.h> #include <linux/xattr.h> #include <linux/exportfs.h> +#include <linux/fileattr.h> #include <linux/uuid.h> #include <linux/namei.h> #include <linux/ratelimit.h> @@ -18,13 +19,13 @@ int ovl_want_write(struct dentry *dentry) { struct ovl_fs *ofs = dentry->d_sb->s_fs_info; - return mnt_want_write(ofs->upper_mnt); + return mnt_want_write(ovl_upper_mnt(ofs)); } void ovl_drop_write(struct dentry *dentry) { struct ovl_fs *ofs = dentry->d_sb->s_fs_info; - mnt_drop_write(ofs->upper_mnt); + mnt_drop_write(ovl_upper_mnt(ofs)); } struct dentry *ovl_workdir(struct dentry *dentry) @@ -50,6 +51,9 @@ const struct cred *ovl_override_creds(struct super_block *sb) */ int ovl_can_decode_fh(struct super_block *sb) { + if (!capable(CAP_DAC_READ_SEARCH)) + return 0; + if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry) return 0; @@ -93,8 +97,24 @@ struct ovl_entry *ovl_alloc_entry(unsigned int numlower) bool ovl_dentry_remote(struct dentry *dentry) { return dentry->d_flags & - (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE | - DCACHE_OP_REAL); + (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); +} + +void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry, + unsigned int mask) +{ + struct ovl_entry *oe = OVL_E(dentry); + unsigned int i, flags = 0; + + if (upperdentry) + flags |= upperdentry->d_flags; + for (i = 0; i < oe->numlower; i++) + flags |= oe->lowerstack[i].dentry->d_flags; + + spin_lock(&dentry->d_lock); + dentry->d_flags &= ~mask; + dentry->d_flags |= flags & mask; + spin_unlock(&dentry->d_lock); } bool ovl_dentry_weird(struct dentry *dentry) @@ -134,7 +154,7 @@ void ovl_path_upper(struct dentry *dentry, struct path *path) { struct ovl_fs *ofs = dentry->d_sb->s_fs_info; - path->mnt = ofs->upper_mnt; + path->mnt = ovl_upper_mnt(ofs); path->dentry = ovl_dentry_upper(dentry); } @@ -174,6 +194,20 @@ enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) return type; } +enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path) +{ + enum ovl_path_type type = ovl_path_type(dentry); + + WARN_ON_ONCE(d_is_dir(dentry)); + + if (!OVL_TYPE_UPPER(type) || OVL_TYPE_MERGE(type)) + ovl_path_lowerdata(dentry, path); + else + ovl_path_upper(dentry, path); + + return type; +} + struct dentry *ovl_dentry_upper(struct dentry *dentry) { return ovl_upperdentry_dereference(OVL_I(d_inode(dentry))); @@ -195,7 +229,7 @@ const struct ovl_layer *ovl_layer_lower(struct dentry *dentry) /* * ovl_dentry_lower() could return either a data dentry or metacopy dentry - * dependig on what is stored in lowerstack[0]. At times we need to find + * depending on what is stored in lowerstack[0]. At times we need to find * lower dentry which has data (and not metacopy dentry). This helper * returns the lower data dentry. */ @@ -216,6 +250,17 @@ struct dentry *ovl_i_dentry_upper(struct inode *inode) return ovl_upperdentry_dereference(OVL_I(inode)); } +void ovl_i_path_real(struct inode *inode, struct path *path) +{ + path->dentry = ovl_i_dentry_upper(inode); + if (!path->dentry) { + path->dentry = OVL_I(inode)->lowerpath.dentry; + path->mnt = OVL_I(inode)->lowerpath.layer->mnt; + } else { + path->mnt = ovl_upper_mnt(OVL_FS(inode->i_sb)); + } +} + struct inode *ovl_inode_upper(struct inode *inode) { struct dentry *upperdentry = ovl_i_dentry_upper(inode); @@ -225,7 +270,9 @@ struct inode *ovl_inode_upper(struct inode *inode) struct inode *ovl_inode_lower(struct inode *inode) { - return OVL_I(inode)->lower; + struct dentry *lowerdentry = OVL_I(inode)->lowerpath.dentry; + + return lowerdentry ? d_inode(lowerdentry) : NULL; } struct inode *ovl_inode_real(struct inode *inode) @@ -386,24 +433,6 @@ void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect) oi->redirect = redirect; } -void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, - struct dentry *lowerdentry, struct dentry *lowerdata) -{ - struct inode *realinode = d_inode(upperdentry ?: lowerdentry); - - if (upperdentry) - OVL_I(inode)->__upperdentry = upperdentry; - if (lowerdentry) - OVL_I(inode)->lower = igrab(d_inode(lowerdentry)); - if (lowerdata) - OVL_I(inode)->lowerdata = igrab(d_inode(lowerdata)); - - ovl_copyattr(realinode, inode); - ovl_copyflags(realinode, inode); - if (!inode->i_ino) - inode->i_ino = realinode->i_ino; -} - void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) { struct inode *upperinode = d_inode(upperdentry); @@ -416,34 +445,34 @@ void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) smp_wmb(); OVL_I(inode)->__upperdentry = upperdentry; if (inode_unhashed(inode)) { - if (!inode->i_ino) - inode->i_ino = upperinode->i_ino; inode->i_private = upperinode; __insert_inode_hash(inode, (unsigned long) upperinode); } } -static void ovl_dentry_version_inc(struct dentry *dentry, bool impurity) +static void ovl_dir_version_inc(struct dentry *dentry, bool impurity) { struct inode *inode = d_inode(dentry); WARN_ON(!inode_is_locked(inode)); + WARN_ON(!d_is_dir(dentry)); /* - * Version is used by readdir code to keep cache consistent. For merge - * dirs all changes need to be noted. For non-merge dirs, cache only - * contains impure (ones which have been copied up and have origins) - * entries, so only need to note changes to impure entries. + * Version is used by readdir code to keep cache consistent. + * For merge dirs (or dirs with origin) all changes need to be noted. + * For non-merge dirs, cache contains only impure entries (i.e. ones + * which have been copied up and have origins), so only need to note + * changes to impure entries. */ - if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity) + if (!ovl_dir_is_real(dentry) || impurity) OVL_I(inode)->version++; } void ovl_dir_modified(struct dentry *dentry, bool impurity) { /* Copy mtime/ctime */ - ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry)); + ovl_copyattr(d_inode(dentry)); - ovl_dentry_version_inc(dentry, impurity); + ovl_dir_version_inc(dentry, impurity); } u64 ovl_dentry_version_get(struct dentry *dentry) @@ -461,9 +490,35 @@ bool ovl_is_whiteout(struct dentry *dentry) return inode && IS_WHITEOUT(inode); } -struct file *ovl_path_open(struct path *path, int flags) +struct file *ovl_path_open(const struct path *path, int flags) { - return dentry_open(path, flags | O_NOATIME, current_cred()); + struct inode *inode = d_inode(path->dentry); + struct user_namespace *real_mnt_userns = mnt_user_ns(path->mnt); + int err, acc_mode; + + if (flags & ~(O_ACCMODE | O_LARGEFILE)) + BUG(); + + switch (flags & O_ACCMODE) { + case O_RDONLY: + acc_mode = MAY_READ; + break; + case O_WRONLY: + acc_mode = MAY_WRITE; + break; + default: + BUG(); + } + + err = inode_permission(real_mnt_userns, inode, acc_mode | MAY_OPEN); + if (err) + return ERR_PTR(err); + + /* O_NOATIME is an optimization, don't fail if not permitted */ + if (inode_owner_or_capable(real_mnt_userns, inode)) + flags |= O_NOATIME; + + return dentry_open(path, flags, current_cred()); } /* Caller should hold ovl_inode->lock */ @@ -523,11 +578,11 @@ void ovl_copy_up_end(struct dentry *dentry) ovl_inode_unlock(d_inode(dentry)); } -bool ovl_check_origin_xattr(struct dentry *dentry) +bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path) { int res; - res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0); + res = ovl_path_getxattr(ofs, path, OVL_XATTR_ORIGIN, NULL, 0); /* Zero size value means "copied up but origin unknown" */ if (res >= 0) @@ -536,35 +591,59 @@ bool ovl_check_origin_xattr(struct dentry *dentry) return false; } -bool ovl_check_dir_xattr(struct dentry *dentry, const char *name) +bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path, + enum ovl_xattr ox) { int res; char val; - if (!d_is_dir(dentry)) + if (!d_is_dir(path->dentry)) return false; - res = vfs_getxattr(dentry, name, &val, 1); + res = ovl_path_getxattr(ofs, path, ox, &val, 1); if (res == 1 && val == 'y') return true; return false; } -int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, - const char *name, const void *value, size_t size, +#define OVL_XATTR_OPAQUE_POSTFIX "opaque" +#define OVL_XATTR_REDIRECT_POSTFIX "redirect" +#define OVL_XATTR_ORIGIN_POSTFIX "origin" +#define OVL_XATTR_IMPURE_POSTFIX "impure" +#define OVL_XATTR_NLINK_POSTFIX "nlink" +#define OVL_XATTR_UPPER_POSTFIX "upper" +#define OVL_XATTR_METACOPY_POSTFIX "metacopy" +#define OVL_XATTR_PROTATTR_POSTFIX "protattr" + +#define OVL_XATTR_TAB_ENTRY(x) \ + [x] = { [false] = OVL_XATTR_TRUSTED_PREFIX x ## _POSTFIX, \ + [true] = OVL_XATTR_USER_PREFIX x ## _POSTFIX } + +const char *const ovl_xattr_table[][2] = { + OVL_XATTR_TAB_ENTRY(OVL_XATTR_OPAQUE), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_REDIRECT), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_ORIGIN), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_IMPURE), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_NLINK), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_UPPER), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_PROTATTR), +}; + +int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry, + enum ovl_xattr ox, const void *value, size_t size, int xerr) { int err; - struct ovl_fs *ofs = dentry->d_sb->s_fs_info; if (ofs->noxattr) return xerr; - err = ovl_do_setxattr(upperdentry, name, value, size, 0); + err = ovl_setxattr(ofs, upperdentry, ox, value, size); if (err == -EOPNOTSUPP) { - pr_warn("cannot set %s xattr on upper\n", name); + pr_warn("cannot set %s xattr on upper\n", ovl_xattr(ofs, ox)); ofs->noxattr = true; return xerr; } @@ -574,6 +653,7 @@ int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry) { + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); int err; if (ovl_test_flag(OVL_IMPURE, d_inode(dentry))) @@ -583,27 +663,93 @@ int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry) * Do not fail when upper doesn't support xattrs. * Upper inodes won't have origin nor redirect xattr anyway. */ - err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE, - "y", 1, 0); + err = ovl_check_setxattr(ofs, upperdentry, OVL_XATTR_IMPURE, "y", 1, 0); if (!err) ovl_set_flag(OVL_IMPURE, d_inode(dentry)); return err; } -void ovl_set_flag(unsigned long flag, struct inode *inode) -{ - set_bit(flag, &OVL_I(inode)->flags); -} -void ovl_clear_flag(unsigned long flag, struct inode *inode) +#define OVL_PROTATTR_MAX 32 /* Reserved for future flags */ + +void ovl_check_protattr(struct inode *inode, struct dentry *upper) { - clear_bit(flag, &OVL_I(inode)->flags); + struct ovl_fs *ofs = OVL_FS(inode->i_sb); + u32 iflags = inode->i_flags & OVL_PROT_I_FLAGS_MASK; + char buf[OVL_PROTATTR_MAX+1]; + int res, n; + + res = ovl_getxattr_upper(ofs, upper, OVL_XATTR_PROTATTR, buf, + OVL_PROTATTR_MAX); + if (res < 0) + return; + + /* + * Initialize inode flags from overlay.protattr xattr and upper inode + * flags. If upper inode has those fileattr flags set (i.e. from old + * kernel), we do not clear them on ovl_get_inode(), but we will clear + * them on next fileattr_set(). + */ + for (n = 0; n < res; n++) { + if (buf[n] == 'a') + iflags |= S_APPEND; + else if (buf[n] == 'i') + iflags |= S_IMMUTABLE; + else + break; + } + + if (!res || n < res) { + pr_warn_ratelimited("incompatible overlay.protattr format (%pd2, len=%d)\n", + upper, res); + } else { + inode_set_flags(inode, iflags, OVL_PROT_I_FLAGS_MASK); + } } -bool ovl_test_flag(unsigned long flag, struct inode *inode) +int ovl_set_protattr(struct inode *inode, struct dentry *upper, + struct fileattr *fa) { - return test_bit(flag, &OVL_I(inode)->flags); + struct ovl_fs *ofs = OVL_FS(inode->i_sb); + char buf[OVL_PROTATTR_MAX]; + int len = 0, err = 0; + u32 iflags = 0; + + BUILD_BUG_ON(HWEIGHT32(OVL_PROT_FS_FLAGS_MASK) > OVL_PROTATTR_MAX); + + if (fa->flags & FS_APPEND_FL) { + buf[len++] = 'a'; + iflags |= S_APPEND; + } + if (fa->flags & FS_IMMUTABLE_FL) { + buf[len++] = 'i'; + iflags |= S_IMMUTABLE; + } + + /* + * Do not allow to set protection flags when upper doesn't support + * xattrs, because we do not set those fileattr flags on upper inode. + * Remove xattr if it exist and all protection flags are cleared. + */ + if (len) { + err = ovl_check_setxattr(ofs, upper, OVL_XATTR_PROTATTR, + buf, len, -EPERM); + } else if (inode->i_flags & OVL_PROT_I_FLAGS_MASK) { + err = ovl_removexattr(ofs, upper, OVL_XATTR_PROTATTR); + if (err == -EOPNOTSUPP || err == -ENODATA) + err = 0; + } + if (err) + return err; + + inode_set_flags(inode, iflags, OVL_PROT_I_FLAGS_MASK); + + /* Mask out the fileattr flags that should not be set in upper inode */ + fa->flags &= ~OVL_PROT_FS_FLAGS_MASK; + fa->fsx_xflags &= ~OVL_PROT_FSX_FLAGS_MASK; + + return 0; } /** @@ -673,6 +819,7 @@ bool ovl_need_index(struct dentry *dentry) /* Caller must hold OVL_I(inode)->lock */ static void ovl_cleanup_index(struct dentry *dentry) { + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); struct dentry *indexdir = ovl_indexdir(dentry->d_sb); struct inode *dir = indexdir->d_inode; struct dentry *lowerdentry = ovl_dentry_lower(dentry); @@ -682,7 +829,7 @@ static void ovl_cleanup_index(struct dentry *dentry) struct qstr name = { }; int err; - err = ovl_get_index_name(lowerdentry, &name); + err = ovl_get_index_name(ofs, lowerdentry, &name); if (err) goto fail; @@ -705,16 +852,17 @@ static void ovl_cleanup_index(struct dentry *dentry) } inode_lock_nested(dir, I_MUTEX_PARENT); - index = lookup_one_len(name.name, indexdir, name.len); + index = ovl_lookup_upper(ofs, name.name, indexdir, name.len); err = PTR_ERR(index); if (IS_ERR(index)) { index = NULL; } else if (ovl_index_all(dentry->d_sb)) { /* Whiteout orphan index to block future open by handle */ - err = ovl_cleanup_and_whiteout(indexdir, dir, index); + err = ovl_cleanup_and_whiteout(OVL_FS(dentry->d_sb), + dir, index); } else { /* Cleanup orphan index entries */ - err = ovl_cleanup(dir, index); + err = ovl_cleanup(ofs, dir, index); } inode_unlock(dir); @@ -823,18 +971,25 @@ err: } /* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */ -int ovl_check_metacopy_xattr(struct dentry *dentry) +int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path) { int res; /* Only regular files can have metacopy xattr */ - if (!S_ISREG(d_inode(dentry)->i_mode)) + if (!S_ISREG(d_inode(path->dentry)->i_mode)) return 0; - res = vfs_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0); + res = ovl_path_getxattr(ofs, path, OVL_XATTR_METACOPY, NULL, 0); if (res < 0) { if (res == -ENODATA || res == -EOPNOTSUPP) return 0; + /* + * getxattr on user.* may fail with EACCES in case there's no + * read permission on the inode. Not much we can do, other than + * tell the caller that this is not a metacopy inode. + */ + if (ofs->config.userxattr && res == -EACCES) + return 0; goto out; } @@ -860,49 +1015,26 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry) return (oe->numlower > 1); } -ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value, - size_t padding) -{ - ssize_t res; - char *buf = NULL; - - res = vfs_getxattr(dentry, name, NULL, 0); - if (res < 0) { - if (res == -ENODATA || res == -EOPNOTSUPP) - return -ENODATA; - goto fail; - } - - if (res != 0) { - buf = kzalloc(res + padding, GFP_KERNEL); - if (!buf) - return -ENOMEM; - - res = vfs_getxattr(dentry, name, buf, res); - if (res < 0) - goto fail; - } - *value = buf; - - return res; - -fail: - pr_warn_ratelimited("failed to get xattr %s: err=%zi)\n", - name, res); - kfree(buf); - return res; -} - -char *ovl_get_redirect_xattr(struct dentry *dentry, int padding) +char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding) { int res; char *s, *next, *buf = NULL; - res = ovl_getxattr(dentry, OVL_XATTR_REDIRECT, &buf, padding + 1); - if (res == -ENODATA) + res = ovl_path_getxattr(ofs, path, OVL_XATTR_REDIRECT, NULL, 0); + if (res == -ENODATA || res == -EOPNOTSUPP) return NULL; if (res < 0) - return ERR_PTR(res); + goto fail; + if (res == 0) + goto invalid; + + buf = kzalloc(res + padding + 1, GFP_KERNEL); + if (!buf) + return ERR_PTR(-ENOMEM); + + res = ovl_path_getxattr(ofs, path, OVL_XATTR_REDIRECT, buf, res); + if (res < 0) + goto fail; if (res == 0) goto invalid; @@ -921,6 +1053,67 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding) invalid: pr_warn_ratelimited("invalid redirect (%s)\n", buf); res = -EINVAL; + goto err_free; +fail: + pr_warn_ratelimited("failed to get redirect (%i)\n", res); +err_free: kfree(buf); return ERR_PTR(res); } + +/* + * ovl_sync_status() - Check fs sync status for volatile mounts + * + * Returns 1 if this is not a volatile mount and a real sync is required. + * + * Returns 0 if syncing can be skipped because mount is volatile, and no errors + * have occurred on the upperdir since the mount. + * + * Returns -errno if it is a volatile mount, and the error that occurred since + * the last mount. If the error code changes, it'll return the latest error + * code. + */ + +int ovl_sync_status(struct ovl_fs *ofs) +{ + struct vfsmount *mnt; + + if (ovl_should_sync(ofs)) + return 1; + + mnt = ovl_upper_mnt(ofs); + if (!mnt) + return 0; + + return errseq_check(&mnt->mnt_sb->s_wb_err, ofs->errseq); +} + +/* + * ovl_copyattr() - copy inode attributes from layer to ovl inode + * + * When overlay copies inode information from an upper or lower layer to the + * relevant overlay inode it will apply the idmapping of the upper or lower + * layer when doing so ensuring that the ovl inode ownership will correctly + * reflect the ownership of the idmapped upper or lower layer. For example, an + * idmapped upper or lower layer mapping id 1001 to id 1000 will take care to + * map any lower or upper inode owned by id 1001 to id 1000. These mapping + * helpers are nops when the relevant layer isn't idmapped. + */ +void ovl_copyattr(struct inode *inode) +{ + struct path realpath; + struct inode *realinode; + struct user_namespace *real_mnt_userns; + + ovl_i_path_real(inode, &realpath); + realinode = d_inode(realpath.dentry); + real_mnt_userns = mnt_user_ns(realpath.mnt); + + inode->i_uid = i_uid_into_mnt(real_mnt_userns, realinode); + inode->i_gid = i_gid_into_mnt(real_mnt_userns, realinode); + inode->i_mode = realinode->i_mode; + inode->i_atime = realinode->i_atime; + inode->i_mtime = realinode->i_mtime; + inode->i_ctime = realinode->i_ctime; + i_size_write(inode, i_size_read(realinode)); +} |