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From: Jeff Layton <jlayton@kernel.org>
To: ceph-devel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
	dhowells@redhat.com, xiubli@redhat.com, lhenriques@suse.de,
	khiremat@redhat.com, ebiggers@kernel.org
Subject: [RFC PATCH v8 03/24] fscrypt: export fscrypt_fname_encrypt and fscrypt_fname_encrypted_size
Date: Thu, 26 Aug 2021 12:19:53 -0400	[thread overview]
Message-ID: <20210826162014.73464-4-jlayton@kernel.org> (raw)
In-Reply-To: <20210826162014.73464-1-jlayton@kernel.org>

For ceph, we want to use our own scheme for handling filenames that are
are longer than NAME_MAX after encryption and base64 encoding. This
allows us to have a consistent view of the encrypted filenames for
clients that don't support fscrypt and clients that do but that don't
have the key.

Currently, fs/crypto only supports encrypting filenames using
fscrypt_setup_filename, but that also handles encoding nokey names. Ceph
can't use that because it handles nokey names in a different way.

Export fscrypt_fname_encrypt. Rename fscrypt_fname_encrypted_size to
__fscrypt_fname_encrypted_size and add a new wrapper called
fscrypt_fname_encrypted_size that takes an inode argument rather than a
pointer to a fscrypt_policy union.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/crypto/fname.c           | 32 +++++++++++++++++++++++++++-----
 fs/crypto/fscrypt_private.h |  9 +++------
 fs/crypto/hooks.c           |  6 +++---
 include/linux/fscrypt.h     |  4 ++++
 4 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 02555a31875a..7195b64aea77 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -130,6 +130,7 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 
 	return 0;
 }
+EXPORT_SYMBOL(fscrypt_fname_encrypt);
 
 /**
  * fname_decrypt() - decrypt a filename
@@ -257,9 +258,9 @@ int fscrypt_base64url_decode(const char *src, int srclen, u8 *dst)
 }
 EXPORT_SYMBOL(fscrypt_base64url_decode);
 
-bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
-				  u32 orig_len, u32 max_len,
-				  u32 *encrypted_len_ret)
+bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
+				    u32 orig_len, u32 max_len,
+				    u32 *encrypted_len_ret)
 {
 	int padding = 4 << (fscrypt_policy_flags(policy) &
 			    FSCRYPT_POLICY_FLAGS_PAD_MASK);
@@ -273,6 +274,28 @@ bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
 	return true;
 }
 
+/**
+ * fscrypt_fname_encrypted_size() - calculate length of encrypted filename
+ * @inode: 		parent inode of dentry name being encrypted
+ * @orig_len:		length of the original filename
+ * @max_len:		maximum length to return
+ * @encrypted_len_ret:	where calculated length should be returned (on success)
+ *
+ * Filenames must be padded out to at least the end of an fscrypt block before
+ * encrypting them. This calculates the length of an encrypted filename.
+ *
+ * Return: false if the orig_len is shorter than max_len. Otherwise, true and
+ * 	   fill out encrypted_len_ret with the length (up to max_len).
+ */
+bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
+				  u32 max_len, u32 *encrypted_len_ret)
+{
+	return __fscrypt_fname_encrypted_size(&inode->i_crypt_info->ci_policy,
+					      orig_len, max_len,
+					      encrypted_len_ret);
+}
+EXPORT_SYMBOL(fscrypt_fname_encrypted_size);
+
 /**
  * fscrypt_fname_alloc_buffer() - allocate a buffer for presented filenames
  * @max_encrypted_len: maximum length of encrypted filenames the buffer will be
@@ -428,8 +451,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 		return ret;
 
 	if (fscrypt_has_encryption_key(dir)) {
-		if (!fscrypt_fname_encrypted_size(&dir->i_crypt_info->ci_policy,
-						  iname->len,
+		if (!fscrypt_fname_encrypted_size(dir, iname->len,
 						  dir->i_sb->s_cop->max_namelen,
 						  &fname->crypto_buf.len))
 			return -ENAMETOOLONG;
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 3fa965eb3336..195de6d0db40 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -292,14 +292,11 @@ void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
 			 const struct fscrypt_info *ci);
 
 /* fname.c */
-int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
-			  u8 *out, unsigned int olen);
-bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
-				  u32 orig_len, u32 max_len,
-				  u32 *encrypted_len_ret);
+bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
+				    u32 orig_len, u32 max_len,
+                                    u32 *encrypted_len_ret);
 
 /* hkdf.c */
-
 struct fscrypt_hkdf {
 	struct crypto_shash *hmac_tfm;
 };
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index a73b0376e6f3..e65c19aae041 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -228,9 +228,9 @@ int fscrypt_prepare_symlink(struct inode *dir, const char *target,
 	 * counting it (even though it is meaningless for ciphertext) is simpler
 	 * for now since filesystems will assume it is there and subtract it.
 	 */
-	if (!fscrypt_fname_encrypted_size(policy, len,
-					  max_len - sizeof(struct fscrypt_symlink_data),
-					  &disk_link->len))
+	if (!__fscrypt_fname_encrypted_size(policy, len,
+					    max_len - sizeof(struct fscrypt_symlink_data),
+					    &disk_link->len))
 		return -ENAMETOOLONG;
 	disk_link->len += sizeof(struct fscrypt_symlink_data);
 
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 07144330f975..64281ba4be2b 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -210,8 +210,12 @@ void fscrypt_free_inode(struct inode *inode);
 int fscrypt_drop_inode(struct inode *inode);
 
 /* fname.c */
+int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
+			  u8 *out, unsigned int olen);
 int fscrypt_base64url_encode(const u8 *src, int len, char *dst);
 int fscrypt_base64url_decode(const char *src, int len, u8 *dst);
+bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
+				  u32 max_len, u32 *encrypted_len_ret);
 int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname,
 			   int lookup, struct fscrypt_name *fname);
 
-- 
2.31.1


  parent reply	other threads:[~2021-08-26 16:20 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-26 16:19 [RFC PATCH v8 00/24] ceph+fscrypt: context, filename and symlink support Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 01/24] vfs: export new_inode_pseudo Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 02/24] fscrypt: export fscrypt_base64url_encode and fscrypt_base64url_decode Jeff Layton
2021-08-26 16:19 ` Jeff Layton [this message]
2021-08-26 16:19 ` [RFC PATCH v8 04/24] fscrypt: add fscrypt_context_for_new_inode Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 05/24] ceph: preallocate inode for ops that may create one Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 06/24] ceph: parse new fscrypt_auth and fscrypt_file fields in inode traces Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 07/24] ceph: add fscrypt_* handling to caps.c Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 08/24] ceph: crypto context handling for ceph Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 09/24] ceph: add ability to set fscrypt_auth via setattr Jeff Layton
2021-08-31  5:06   ` Xiubo Li
2021-08-31 12:43     ` Jeff Layton
2021-08-31 13:22       ` Xiubo Li
2021-08-31 13:50         ` Jeff Layton
2021-08-31 17:54           ` Eric Biggers
2021-09-01  0:53             ` Xiubo Li
2021-09-01  1:13           ` Xiubo Li
2021-09-01 12:02             ` Jeff Layton
2021-09-02  1:54               ` Xiubo Li
2021-08-26 16:20 ` [RFC PATCH v8 10/24] ceph: implement -o test_dummy_encryption mount option Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 11/24] ceph: add fscrypt ioctls Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 12/24] ceph: decode alternate_name in lease info Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 13/24] ceph: make ceph_msdc_build_path use ref-walk Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 14/24] ceph: add encrypted fname handling to ceph_mdsc_build_path Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 15/24] ceph: send altname in MClientRequest Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 16/24] ceph: encode encrypted name in dentry release Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 17/24] ceph: properly set DCACHE_NOKEY_NAME flag in lookup Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 18/24] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 19/24] ceph: add helpers for converting names for userland presentation Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 20/24] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 21/24] ceph: add support to readdir for encrypted filenames Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 22/24] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 23/24] ceph: make ceph_get_name decrypt filenames Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 24/24] ceph: add a new ceph.fscrypt.auth vxattr Jeff Layton

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