[PATCH 5.10 05/29] ubifs: report correct st_size for encrypted symlinks

Greg Kroah-Hartman
2021-09-06T12:57:03Z

From: Eric Biggers <ebiggers@google.com>

commit 064c734986011390b4d111f1a99372b7f26c3850 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ubifs/file.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1629,6 +1629,16 @@ static const char *ubifs_get_link(struct
return fscrypt_get_symlink(inode, ui->data, ui->data_len, done);
}

+static int ubifs_symlink_getattr(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int query_flags)
+{
+ ubifs_getattr(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,
@@ -1654,7 +1664,7 @@ const struct inode_operations ubifs_file
const struct inode_operations ubifs_symlink_inode_operations = {
.get_link = ubifs_get_link,
.setattr = ubifs_setattr,
- .getattr = ubifs_getattr,
+ .getattr = ubifs_symlink_getattr,
#ifdef CONFIG_UBIFS_FS_XATTR
.listxattr = ubifs_listxattr,
#endif