diff options
Diffstat (limited to 'fs/overlayfs/namei.c')
| -rw-r--r-- | fs/overlayfs/namei.c | 31 |
1 files changed, 28 insertions, 3 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 0b8b28392eb7..1fc68b59fa5d 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -230,13 +230,26 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d, struct dentry **ret, bool drop_negative) { struct ovl_fs *ofs = OVL_FS(d->sb); - struct dentry *this; + struct dentry *this = NULL; + const char *warn; struct path path; int err; bool last_element = !post[0]; bool is_upper = d->layer->idx == 0; char val; + /* + * We allow filesystems that are case-folding capable but deny composing + * ovl stack from case-folded directories. If someone has enabled case + * folding on a directory on underlying layer, the warranty of the ovl + * stack is voided. + */ + if (ovl_dentry_casefolded(base)) { + warn = "case folded parent"; + err = -ESTALE; + goto out_warn; + } + this = ovl_lookup_positive_unlocked(d, name, base, namelen, drop_negative); if (IS_ERR(this)) { err = PTR_ERR(this); @@ -246,10 +259,17 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d, goto out_err; } + if (ovl_dentry_casefolded(this)) { + warn = "case folded child"; + err = -EREMOTE; + goto out_warn; + } + if (ovl_dentry_weird(this)) { /* Don't support traversing automounts and other weirdness */ + warn = "unsupported object type"; err = -EREMOTE; - goto out_err; + goto out_warn; } path.dentry = this; @@ -283,8 +303,9 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d, } else { if (ovl_lookup_trap_inode(d->sb, this)) { /* Caught in a trap of overlapping layers */ + warn = "overlapping layers"; err = -ELOOP; - goto out_err; + goto out_warn; } if (last_element) @@ -316,6 +337,10 @@ put_and_out: this = NULL; goto out; +out_warn: + pr_warn_ratelimited("failed lookup in %s (%pd2, name='%.*s', err=%i): %s\n", + is_upper ? "upper" : "lower", base, + namelen, name, err, warn); out_err: dput(this); return err; |