[PATCH 5.10 04/29] f2fs: report correct st_size for encrypted symlinks

Greg Kroah-Hartman
2021-09-06T12:57:02Z

From: Eric Biggers <ebiggers@google.com>

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 | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -1307,9 +1307,18 @@ static const char *f2fs_encrypted_get_li
return target;
}

+static int f2fs_encrypted_symlink_getattr(const struct path *path,
+ struct kstat *stat, u32 request_mask,
+ unsigned int query_flags)
+{
+ f2fs_getattr(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,
};