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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 19/24] ceph: add helpers for converting names for userland presentation
Date: Thu, 26 Aug 2021 12:20:09 -0400	[thread overview]
Message-ID: <20210826162014.73464-20-jlayton@kernel.org> (raw)
In-Reply-To: <20210826162014.73464-1-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 b2f01c308885..5bbeb6245eff 100644
--- a/fs/ceph/crypto.c
+++ b/fs/ceph/crypto.c
@@ -176,3 +176,79 @@ int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentr
 	dout("base64-encoded ciphertext name = %.*s\n", elen, buf);
 	return elen;
 }
+
+/**
+ * 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_BASE64URL_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_base64url_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 d5e298383b3e..c2e0cbb5667b 100644
--- a/fs/ceph/crypto.h
+++ b/fs/ceph/crypto.h
@@ -13,6 +13,14 @@ struct ceph_fs_client;
 struct ceph_acl_sec_ctx;
 struct ceph_mds_request;
 
+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
+};
+
 struct ceph_fscrypt_auth {
 	__le32	cfa_version;
 	__le32	cfa_blob_len;
@@ -55,6 +63,22 @@ int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
 void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req, struct ceph_acl_sec_ctx *as);
 int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentry, char *buf);
 
+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)
@@ -83,6 +107,23 @@ static inline int ceph_encode_encrypted_fname(const struct inode *parent,
 {
 	return -EOPNOTSUPP;
 }
+
+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
-- 
2.31.1


  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 ` [RFC PATCH v8 03/24] fscrypt: export fscrypt_fname_encrypt and fscrypt_fname_encrypted_size Jeff Layton
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 ` Jeff Layton [this message]
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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