[PATCH 4.9 20/36] Revert "ecryptfs: replace BUG_ON with error handling code"

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit e1436df2f2550bc89d832ffd456373fdf5d5b5d7 upstream.

This reverts commit 2c2a7552dd6465e8fde6bc9cccf8d66ed1c1eb72.

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: 2c2a7552dd64 ("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>
---
 fs/ecryptfs/crypto.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -339,10 +339,8 @@ static int crypt_scatterlist(struct ecry
 	struct extent_crypt_result ecr;
 	int rc = 0;
 
-	if (!crypt_stat || !crypt_stat->tfm
-	       || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
-		return -EINVAL;
-
+	BUG_ON(!crypt_stat || !crypt_stat->tfm
+	       || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
 	if (unlikely(ecryptfs_verbosity > 0)) {
 		ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
 				crypt_stat->key_size);