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From: Jeff Layton <jlayton@kernel.org>
To: ceph-devel@vger.kernel.org
Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [RFC PATCH v5 15/19] ceph: add helpers for converting names for userland presentation
Date: Fri, 26 Mar 2021 13:32:23 -0400
Message-ID: <20210326173227.96363-16-jlayton@kernel.org> (raw)
In-Reply-To: <20210326173227.96363-1-jlayton@kernel.org>

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/crypto.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ceph/crypto.h | 41 ++++++++++++++++++++++++++
 2 files changed, 117 insertions(+)

diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
index f037a4939026..9fed68f37629 100644
--- a/fs/ceph/crypto.c
+++ b/fs/ceph/crypto.c
@@ -107,3 +107,79 @@ int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
 		ceph_pagelist_release(pagelist);
 	return ret;
 }
+
+/**
+ * ceph_fname_to_usr - convert a filename for userland presentation
+ * @fname: ceph_fname to be converted
+ * @tname: temporary name buffer to use for conversion (may be NULL)
+ * @oname: where converted name should be placed
+ * @is_nokey: set to true if key wasn't available during conversion (may be NULL)
+ *
+ * Given a filename (usually from the MDS), format it for presentation to
+ * userland. If @parent is not encrypted, just pass it back as-is.
+ *
+ * Otherwise, base64 decode the string, and then ask fscrypt to format it
+ * for userland presentation.
+ *
+ * Returns 0 on success or negative error code on error.
+ */
+int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
+		      struct fscrypt_str *oname, bool *is_nokey)
+{
+	int ret;
+	struct fscrypt_str _tname = FSTR_INIT(NULL, 0);
+	struct fscrypt_str iname;
+
+	if (!IS_ENCRYPTED(fname->dir)) {
+		oname->name = fname->name;
+		oname->len = fname->name_len;
+		return 0;
+	}
+
+	/* Sanity check that the resulting name will fit in the buffer */
+	if (fname->name_len > FSCRYPT_BASE64_CHARS(NAME_MAX))
+		return -EIO;
+
+	ret = __fscrypt_prepare_readdir(fname->dir);
+	if (ret)
+		return ret;
+
+	/*
+	 * Use the raw dentry name as sent by the MDS instead of
+	 * generating a nokey name via fscrypt.
+	 */
+	if (!fscrypt_has_encryption_key(fname->dir)) {
+		memcpy(oname->name, fname->name, fname->name_len);
+		oname->len = fname->name_len;
+		if (is_nokey)
+			*is_nokey = true;
+		return 0;
+	}
+
+	if (fname->ctext_len == 0) {
+		int declen;
+
+		if (!tname) {
+			ret = fscrypt_fname_alloc_buffer(NAME_MAX, &_tname);
+			if (ret)
+				return ret;
+			tname = &_tname;
+		}
+
+		declen = fscrypt_base64_decode(fname->name, fname->name_len, tname->name);
+		if (declen <= 0) {
+			ret = -EIO;
+			goto out;
+		}
+		iname.name = tname->name;
+		iname.len = declen;
+	} else {
+		iname.name = fname->ctext;
+		iname.len = fname->ctext_len;
+	}
+
+	ret = fscrypt_fname_disk_to_usr(fname->dir, 0, 0, &iname, oname);
+out:
+	fscrypt_fname_free_buffer(&_tname);
+	return ret;
+}
diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
index 331b9c8da7fb..5a3fb68eb814 100644
--- a/fs/ceph/crypto.h
+++ b/fs/ceph/crypto.h
@@ -11,6 +11,14 @@
 
 #define	CEPH_XATTR_NAME_ENCRYPTION_CONTEXT	"encryption.ctx"
 
+struct ceph_fname {
+	struct inode	*dir;
+	char 		*name;		// b64 encoded, possibly hashed
+	unsigned char	*ctext;		// binary crypttext (if any)
+	u32		name_len;	// length of name buffer
+	u32		ctext_len;	// length of crypttext
+};
+
 #ifdef CONFIG_FS_ENCRYPTION
 
 /*
@@ -37,6 +45,22 @@ static inline void ceph_fscrypt_free_dummy_policy(struct ceph_fs_client *fsc)
 int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
 				 struct ceph_acl_sec_ctx *as);
 
+static inline int ceph_fname_alloc_buffer(struct inode *parent, struct fscrypt_str *fname)
+{
+	if (!IS_ENCRYPTED(parent))
+		return 0;
+	return fscrypt_fname_alloc_buffer(NAME_MAX, fname);
+}
+
+static inline void ceph_fname_free_buffer(struct inode *parent, struct fscrypt_str *fname)
+{
+	if (IS_ENCRYPTED(parent))
+		fscrypt_fname_free_buffer(fname);
+}
+
+int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
+			struct fscrypt_str *oname, bool *is_nokey);
+
 #else /* CONFIG_FS_ENCRYPTION */
 
 static inline void ceph_fscrypt_set_ops(struct super_block *sb)
@@ -55,6 +79,23 @@ static inline int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *
 	return 0;
 }
 
+static inline int ceph_fname_alloc_buffer(struct inode *parent, struct fscrypt_str *fname)
+{
+	return 0;
+}
+
+static inline void ceph_fname_free_buffer(struct inode *parent, struct fscrypt_str *fname)
+{
+}
+
+static inline int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
+				    struct fscrypt_str *oname, bool *is_nokey)
+{
+	oname->name = fname->name;
+	oname->len = fname->name_len;
+	return 0;
+}
+
 #endif /* CONFIG_FS_ENCRYPTION */
 
 #endif
-- 
2.30.2


  parent reply index

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26 17:32 [RFC PATCH v5 00/19] ceph+fscrypt: context, filename and symlink support Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 01/19] vfs: export new_inode_pseudo Jeff Layton
2021-04-08  1:08   ` Eric Biggers
2021-04-08 16:18     ` Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 02/19] fscrypt: export fscrypt_base64_encode and fscrypt_base64_decode Jeff Layton
2021-04-08  1:06   ` Eric Biggers
2021-04-08 16:22     ` Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 03/19] fscrypt: export fscrypt_fname_encrypt and fscrypt_fname_encrypted_size Jeff Layton
2021-04-08  1:19   ` Eric Biggers
2021-03-26 17:32 ` [RFC PATCH v5 04/19] fscrypt: add fscrypt_context_for_new_inode Jeff Layton
2021-04-08  1:21   ` Eric Biggers
2021-04-08 16:27     ` Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 05/19] ceph: crypto context handling for ceph Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 06/19] ceph: implement -o test_dummy_encryption mount option Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 07/19] ceph: preallocate inode for ops that may create one Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 08/19] ceph: add routine to create fscrypt context prior to RPC Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 09/19] ceph: make ceph_msdc_build_path use ref-walk Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 10/19] ceph: add encrypted fname handling to ceph_mdsc_build_path Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 11/19] ceph: decode alternate_name in lease info Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 12/19] ceph: send altname in MClientRequest Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 13/19] ceph: properly set DCACHE_NOKEY_NAME flag in lookup Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 14/19] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2021-03-26 17:32 ` Jeff Layton [this message]
2021-03-26 17:32 ` [RFC PATCH v5 16/19] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 17/19] ceph: add support to readdir for encrypted filenames Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 18/19] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2021-03-26 17:32 ` [RFC PATCH v5 19/19] ceph: add fscrypt ioctls Jeff Layton
2021-04-06 15:38   ` Luis Henriques
2021-04-06 16:03     ` Jeff Layton
2021-04-06 16:24       ` Luis Henriques
2021-04-06 17:27         ` Jeff Layton
2021-04-06 18:04           ` Luis Henriques
2021-04-07 12:47             ` Jeff Layton
2021-03-26 18:38 ` [RFC PATCH v5 00/19] ceph+fscrypt: context, filename and symlink support Jeff Layton
2021-03-31 20:35 ` [RFC PATCH v5 20/19] ceph: make ceph_get_name decrypt filenames Jeff Layton
2021-04-01 11:14   ` Luis Henriques
2021-04-01 12:15     ` Jeff Layton
2021-04-01 13:05       ` Luis Henriques
2021-04-01 13:12         ` Jeff Layton

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