ext4 crypto: fix to check feature status before get policy (0642ea24) · Commits · 戴 / test

When getting fscrypt policy via EXT4_IOC_GET_ENCRYPTION_POLICY, if encryption feature is off, it's better to return EOPNOTSUPP instead of ENODATA, so let's add ext4_has_feature_encrypt() to do the check for that. This makes it so that all fscrypt ioctls consistently check for the encryption feature, and makes ext4 consistent with f2fs in this regard. Signed-off-by:

Chao Yu <yuchao0@huawei.com> [EB - removed unneeded braces, updated the documentation, and added more explanation to commit message] Signed-off-by:

Eric Biggers <ebiggers@google.com>

Documentation/filesystems/fscrypt.rst

+2 −1

Original line number	Diff line number	Diff line
		@@ -562,7 +562,8 @@ FS_IOC_GET_ENCRYPTION_POLICY_EX can fail with the following errors:
		or this kernel is too old to support FS_IOC_GET_ENCRYPTION_POLICY_EX
		(try FS_IOC_GET_ENCRYPTION_POLICY instead)
		- ``EOPNOTSUPP``: the kernel was not configured with encryption
		support for this filesystem
		support for this filesystem, or the filesystem superblock has not
		had encryption enabled on it
		- ``EOVERFLOW``: the file is encrypted and uses a recognized
		encryption policy version, but the policy struct does not fit into
		the provided buffer

fs/ext4/ioctl.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1113,6 +1113,8 @@ resizefs_out:
		#endif
		}
		case EXT4_IOC_GET_ENCRYPTION_POLICY:
		if (!ext4_has_feature_encrypt(sb))
		return -EOPNOTSUPP;
		return fscrypt_ioctl_get_policy(filp, (void __user *)arg);

		case FS_IOC_GET_ENCRYPTION_POLICY_EX:

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