ubifs: report correct st_size for encrypted symlinks

The stat() family of syscalls report the wrong size for encrypted
symlinks, which has caused breakage in several userspace programs.

Fix this by calling fscrypt_symlink_getattr() after ubifs_getattr() for
encrypted symlinks.  This function computes the correct size by reading
and decrypting the symlink target (if it's not already cached).

For more details, see the commit which added fscrypt_symlink_getattr().

Fixes: ca7f85be8d6c ("ubifs: Add support for encrypted symlinks")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210702065350.209646-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 2e4e1d15996931c47132901b807615c2f554a464..5cfa28cd00cdc6bcd216c5178ef173301570560e 100644 (file)
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1630,6 +1630,17 @@ static const char *ubifs_get_link(struct dentry *dentry,
        return fscrypt_get_symlink(inode, ui->data, ui->data_len, done);
 }
 
+static int ubifs_symlink_getattr(struct user_namespace *mnt_userns,
+                                const struct path *path, struct kstat *stat,
+                                u32 request_mask, unsigned int query_flags)
+{
+       ubifs_getattr(mnt_userns, path, stat, request_mask, query_flags);
+
+       if (IS_ENCRYPTED(d_inode(path->dentry)))
+               return fscrypt_symlink_getattr(path, stat);
+       return 0;
+}
+
 const struct address_space_operations ubifs_file_address_operations = {
        .readpage       = ubifs_readpage,
        .writepage      = ubifs_writepage,
@@ -1655,7 +1666,7 @@ const struct inode_operations ubifs_file_inode_operations = {
 const struct inode_operations ubifs_symlink_inode_operations = {
        .get_link    = ubifs_get_link,
        .setattr     = ubifs_setattr,
-       .getattr     = ubifs_getattr,
+       .getattr     = ubifs_symlink_getattr,
        .listxattr   = ubifs_listxattr,
        .update_time = ubifs_update_time,
 };