[PATCH v1] common/encrypt: Do not run _verify_ciphertext_for_encryption_policy on compressed FS

[PATCH v1] common/encrypt: Do not run _verify_ciphertext_for_encryption_policy on compressed FS

[Jan Prusakowski]

_verify_ciphertext_for_encryption_policy() checks if encryption works
correctly by reading encrypted file's contents directly from a block device and
comparing it to a known good ciphertext.

This, however, won't work if the file systems is also compressed. So this patch
disables tests using this function when a compressed FS is used.

Signed-off-by: Jan Prusakowski <jprusakowski@google.com>
---
 common/config  | 1 +
 common/encrypt | 4 ++++
 common/f2fs    | 7 +++++++
 common/rc      | 3 +++
 4 files changed, 15 insertions(+)

diff --git a/common/config b/common/config
index 22b52432..1420e35d 100644
--- a/common/config
+++ b/common/config
@@ -509,6 +509,7 @@ _source_specific_fs()
 		;;
 	f2fs)
 		[ "$MKFS_F2FS_PROG" = "" ] && _fatal "mkfs.f2fs not found"
+		. ./common/f2fs
 		;;
 	nfs)
 		. ./common/nfs
diff --git a/common/encrypt b/common/encrypt
index d4f6e3dc..43ec349b 100644
--- a/common/encrypt
+++ b/common/encrypt
@@ -989,6 +989,10 @@ _verify_ciphertext_for_encryption_policy()
 	fi
 	set_encpolicy_args=${set_encpolicy_args# }
 
+
+	# _verify_ciphertext_for_encryption_policy will fail if the FS is compressed.
+	_require_no_compress
+
 	_require_scratch_encryption $set_encpolicy_args -f $policy_flags
 	if $hw_wrapped_key; then
 		_require_hw_wrapped_key_support $SCRATCH_DEV
diff --git a/common/f2fs b/common/f2fs
index 1b39d8ce..c46e2aa2 100644
--- a/common/f2fs
+++ b/common/f2fs
@@ -25,3 +25,10 @@ _require_scratch_f2fs_compression()
 		_scratch_unmount
 	fi
 }
+
+_require_f2fs_no_compress()
+{
+	if _normalize_mount_options "$MOUNT_OPTIONS" | grep -q "compress"; then
+		_notrun "This test requires no compression enabled"
+	fi
+}
\ No newline at end of file
diff --git a/common/rc b/common/rc
index 81587dad..882e0588 100644
--- a/common/rc
+++ b/common/rc
@@ -2112,6 +2112,9 @@ _require_no_compress()
 	btrfs)
 		_require_btrfs_no_compress
 		;;
+	f2fs)
+		_require_f2fs_no_compress
+		;;
 	*)
 		;;
 	esac
-- 
2.51.0.355.g5224444f11-goog

Re: [PATCH v1] common/encrypt: Do not run _verify_ciphertext_for_encryption_policy on compressed FS

[Eric Biggers]

On Thu, Sep 04, 2025 at 10:54:49AM +0200, Jan Prusakowski wrote:
> _verify_ciphertext_for_encryption_policy() checks if encryption works
> correctly by reading encrypted file's contents directly from a block device and
> comparing it to a known good ciphertext.
> 
> This, however, won't work if the file systems is also compressed. So this patch
> disables tests using this function when a compressed FS is used.

Apparently this is for f2fs.  There isn't really any such thing as a
"compressed filesystem" for f2fs.  Rather, f2fs supports compression on
a per-file basis: the filesystem can contain a mix of compressed and
uncompressed files.  Probably you used 'compression_extension=*', which
caused f2fs to automatically enable compression on the files that
xfstests created, which caused the test failure.  But that behavior is
specific to 'compress_extension=*', not to compression support per se.

> diff --git a/common/f2fs b/common/f2fs
> index 1b39d8ce..c46e2aa2 100644
> --- a/common/f2fs
> +++ b/common/f2fs
> @@ -25,3 +25,10 @@ _require_scratch_f2fs_compression()
>  		_scratch_unmount
>  	fi
>  }
> +
> +_require_f2fs_no_compress()
> +{
> +	if _normalize_mount_options "$MOUNT_OPTIONS" | grep -q "compress"; then
> +		_notrun "This test requires no compression enabled"
> +	fi
> +}

That just checks for compression support, not whether the test file is
actually compressed.

But also, we don't really need to skip these tests.  Instead, how about
using 'chattr +m' to explicitly set the test file to uncompressed?

- Eric

Re: [PATCH v1] common/encrypt: Do not run _verify_ciphertext_for_encryption_policy on compressed FS

[Jan Prusakowski]

On Thu, Sep 4, 2025 at 7:39 PM Eric Biggers <ebiggers@kernel.org> wrote:
> Apparently this is for f2fs.  There isn't really any such thing as a
> "compressed filesystem" for f2fs.  Rather, f2fs supports compression on
> a per-file basis: the filesystem can contain a mix of compressed and
> uncompressed files.  Probably you used 'compression_extension=*', which
> caused f2fs to automatically enable compression on the files that
> xfstests created, which caused the test failure.  But that behavior is
> specific to 'compress_extension=*', not to compression support per se.
>

Yes, I used "compression_extension=*" in my tests.

> But also, we don't really need to skip these tests.  Instead, how about
> using 'chattr +m' to explicitly set the test file to uncompressed?

I tried that and "chattr +m" does not work as it tries to
simultaneously set 2 mutually exclusive compression flags (FS_COMPR_FL
and FS_NOCOMP_FL). However, "chattr -c" on an empty file works, so let
me post a v2 attempt shortly.

Thanks!
Jan