Revert "ecryptfs: replace BUG_ON with error handling code"

stable inclusion
from stable-5.10.40
commit 61b9bc3091a5532ac526e89140a2cf418885fb87
bugzilla: 51882
CVE: NA

--------------------------------

commit e1436df2 upstream.

This reverts commit 2c2a7552.

Because of recent interactions with developers from @umn.edu, all
commits from them have been recently re-reviewed to ensure if they were
correct or not.

Upon review, this commit was found to be incorrect for the reasons
below, so it must be reverted.  It will be fixed up "correctly" in a
later kernel change.

The original commit log for this change was incorrect, no "error
handling code" was added, things will blow up just as badly as before if
any of these cases ever were true.  As this BUG_ON() never fired, and
most of these checks are "obviously" never going to be true, let's just
revert to the original code for now until this gets unwound to be done
correctly in the future.

Cc: Aditya Pakki <pakki001@umn.edu>
Fixes: 2c2a7552 ("ecryptfs: replace BUG_ON with error handling code")
Cc: stable <stable@vger.kernel.org>
Acked-by: Tyler Hicks <code@tyhicks.com>
Link: https://lore.kernel.org/r/20210503115736.2104747-49-gregkh@linuxfoundation.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>