From 753ffce1031a4e1818611f1983a1180084ded011 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Thu, 1 Jul 2021 23:53:48 -0700
Subject: [PATCH] f2fs: report correct st_size for encrypted symlinks

commit 461b43a8f92e68e96c4424b31e15f2b35f1bbfa9 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 f2fs_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: cbaf042a3cc6 ("f2fs crypto: add symlink encryption")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210702065350.209646-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/f2fs/namei.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index e149c8c66a71b..9c528e583c9d5 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -1323,9 +1323,19 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
 	return target;
 }
 
+static int f2fs_encrypted_symlink_getattr(struct user_namespace *mnt_userns,
+					  const struct path *path,
+					  struct kstat *stat, u32 request_mask,
+					  unsigned int query_flags)
+{
+	f2fs_getattr(mnt_userns, path, stat, request_mask, query_flags);
+
+	return fscrypt_symlink_getattr(path, stat);
+}
+
 const struct inode_operations f2fs_encrypted_symlink_inode_operations = {
 	.get_link	= f2fs_encrypted_get_link,
-	.getattr	= f2fs_getattr,
+	.getattr	= f2fs_encrypted_symlink_getattr,
 	.setattr	= f2fs_setattr,
 	.listxattr	= f2fs_listxattr,
 };