Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[cascardo/linux.git] / fs / overlayfs / super.c

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 313f773..4036132 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -16,10 +16,10 @@
 #include <linux/slab.h>
 #include <linux/parser.h>
 #include <linux/module.h>
-#include <linux/pagemap.h>
 #include <linux/sched.h>
 #include <linux/statfs.h>
 #include <linux/seq_file.h>
+#include <linux/posix_acl_xattr.h>
 #include "overlayfs.h"
 
 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
@@ -232,8 +232,11 @@ void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
 void ovl_inode_update(struct inode *inode, struct inode *upperinode)
 {
        WARN_ON(!upperinode);
+       WARN_ON(!inode_unhashed(inode));
        WRITE_ONCE(inode->i_private,
                   (unsigned long) upperinode | OVL_ISUPPER_MASK);
+       if (!S_ISDIR(upperinode->i_mode))
+               __insert_inode_hash(inode, (unsigned long) upperinode);
 }
 
 void ovl_dentry_version_inc(struct dentry *dentry)
@@ -332,7 +335,7 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
        /* Handle recursion */
        return d_real(real, inode, open_flags);
 bug:
-       WARN(1, "ovl_d_real(%pd4, %s:%lu\n): real dentry not found\n", dentry,
+       WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry,
             inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0);
        return dentry;
 }
@@ -404,7 +407,8 @@ static struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
 static bool ovl_dentry_remote(struct dentry *dentry)
 {
        return dentry->d_flags &
-               (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
+               (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
+                DCACHE_OP_REAL);
 }
 
 static bool ovl_dentry_weird(struct dentry *dentry)
@@ -417,7 +421,7 @@ static bool ovl_dentry_weird(struct dentry *dentry)
 
 static inline struct dentry *ovl_lookup_real(struct super_block *ovl_sb,
                                             struct dentry *dir,
-                                            struct qstr *name)
+                                            const struct qstr *name)
 {
        const struct cred *old_cred;
        struct dentry *dentry;
@@ -572,10 +576,15 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
                realinode = d_inode(realdentry);
 
                err = -ENOMEM;
-               inode = ovl_new_inode(dentry->d_sb, realinode->i_mode);
+               if (upperdentry && !d_is_dir(upperdentry)) {
+                       inode = ovl_get_inode(dentry->d_sb, realinode);
+               } else {
+                       inode = ovl_new_inode(dentry->d_sb, realinode->i_mode);
+                       if (inode)
+                               ovl_inode_init(inode, realinode, !!upperdentry);
+               }
                if (!inode)
                        goto out_free_oe;
-               ovl_inode_init(inode, realinode, !!upperdentry);
                ovl_copyattr(realdentry->d_inode, inode);
        }
 
@@ -958,6 +967,96 @@ static unsigned int ovl_split_lowerdirs(char *str)
        return ctr;
 }
 
+static int ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
+                                  struct dentry *dentry, struct inode *inode,
+                                  const char *name, const void *value,
+                                  size_t size, int flags)
+{
+       struct dentry *workdir = ovl_workdir(dentry);
+       struct inode *realinode = ovl_inode_real(inode, NULL);
+       struct posix_acl *acl = NULL;
+       int err;
+
+       /* Check that everything is OK before copy-up */
+       if (value) {
+               acl = posix_acl_from_xattr(&init_user_ns, value, size);
+               if (IS_ERR(acl))
+                       return PTR_ERR(acl);
+       }
+       err = -EOPNOTSUPP;
+       if (!IS_POSIXACL(d_inode(workdir)))
+               goto out_acl_release;
+       if (!realinode->i_op->set_acl)
+               goto out_acl_release;
+       if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) {
+               err = acl ? -EACCES : 0;
+               goto out_acl_release;
+       }
+       err = -EPERM;
+       if (!inode_owner_or_capable(inode))
+               goto out_acl_release;
+
+       posix_acl_release(acl);
+
+       return ovl_setxattr(dentry, inode, handler->name, value, size, flags);
+
+out_acl_release:
+       posix_acl_release(acl);
+       return err;
+}
+
+static int ovl_other_xattr_set(const struct xattr_handler *handler,
+                              struct dentry *dentry, struct inode *inode,
+                              const char *name, const void *value,
+                              size_t size, int flags)
+{
+       return ovl_setxattr(dentry, inode, name, value, size, flags);
+}
+
+static int ovl_own_xattr_set(const struct xattr_handler *handler,
+                            struct dentry *dentry, struct inode *inode,
+                            const char *name, const void *value,
+                            size_t size, int flags)
+{
+       return -EPERM;
+}
+
+static const struct xattr_handler ovl_posix_acl_access_xattr_handler = {
+       .name = XATTR_NAME_POSIX_ACL_ACCESS,
+       .flags = ACL_TYPE_ACCESS,
+       .set = ovl_posix_acl_xattr_set,
+};
+
+static const struct xattr_handler ovl_posix_acl_default_xattr_handler = {
+       .name = XATTR_NAME_POSIX_ACL_DEFAULT,
+       .flags = ACL_TYPE_DEFAULT,
+       .set = ovl_posix_acl_xattr_set,
+};
+
+static const struct xattr_handler ovl_own_xattr_handler = {
+       .prefix = OVL_XATTR_PREFIX,
+       .set = ovl_own_xattr_set,
+};
+
+static const struct xattr_handler ovl_other_xattr_handler = {
+       .prefix = "", /* catch all */
+       .set = ovl_other_xattr_set,
+};
+
+static const struct xattr_handler *ovl_xattr_handlers[] = {
+       &ovl_posix_acl_access_xattr_handler,
+       &ovl_posix_acl_default_xattr_handler,
+       &ovl_own_xattr_handler,
+       &ovl_other_xattr_handler,
+       NULL
+};
+
+static const struct xattr_handler *ovl_xattr_noacl_handlers[] = {
+       &ovl_own_xattr_handler,
+       &ovl_other_xattr_handler,
+       NULL,
+};
+
 static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 {
        struct path upperpath = { NULL, NULL };
@@ -1170,6 +1269,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 
        sb->s_magic = OVERLAYFS_SUPER_MAGIC;
        sb->s_op = &ovl_super_operations;
+       if (IS_ENABLED(CONFIG_FS_POSIX_ACL))
+               sb->s_xattr = ovl_xattr_handlers;
+       else
+               sb->s_xattr = ovl_xattr_noacl_handlers;
        sb->s_root = root_dentry;
        sb->s_fs_info = ufs;
        sb->s_flags |= MS_POSIXACL;