[RFC PATCH v4 05/17] ceph: crypto context handling for ceph

Jeff Layton
2021-01-20T18:33:58Z

Store the fscrypt context for an inode as an encryption.ctx xattr.
When we get a new inode in a trace, set the S_ENCRYPTED bit if
the xattr blob has an encryption.ctx xattr.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/Makefile | 1 +
fs/ceph/crypto.c | 42 ++++++++++++++++++++++++++++++++++++++++++
fs/ceph/crypto.h | 24 ++++++++++++++++++++++++
fs/ceph/inode.c | 6 ++++++
fs/ceph/super.c | 3 +++
fs/ceph/super.h | 1 +
fs/ceph/xattr.c | 32 ++++++++++++++++++++++++++++++++
7 files changed, 109 insertions(+)
create mode 100644 fs/ceph/crypto.c
create mode 100644 fs/ceph/crypto.h

diff --git a/fs/ceph/Makefile b/fs/ceph/Makefile
index 50c635dc7f71..1f77ca04c426 100644
--- a/fs/ceph/Makefile
+++ b/fs/ceph/Makefile
@@ -12,3 +12,4 @@ ceph-y := super.o inode.o dir.o file.o locks.o addr.o ioctl.o \

ceph-$(CONFIG_CEPH_FSCACHE) += cache.o
ceph-$(CONFIG_CEPH_FS_POSIX_ACL) += acl.o
+ceph-$(CONFIG_FS_ENCRYPTION) += crypto.o
diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
new file mode 100644
index 000000000000..dbe8b60fd1b0
--- /dev/null
+++ b/fs/ceph/crypto.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ceph/ceph_debug.h>
+#include <linux/xattr.h>
+#include <linux/fscrypt.h>
+
+#include "super.h"
+#include "crypto.h"
+
+static int ceph_crypt_get_context(struct inode *inode, void *ctx, size_t len)
+{
+ return __ceph_getxattr(inode, CEPH_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
+}
+
+static int ceph_crypt_set_context(struct inode *inode, const void *ctx, size_t len, void *fs_data)
+{
+ int ret;
+
+ WARN_ON_ONCE(fs_data);
+ ret = __ceph_setxattr(inode, CEPH_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len, XATTR_CREATE);
+ if (ret == 0)
+ inode_set_flags(inode, S_ENCRYPTED, S_ENCRYPTED);
+ return ret;
+}
+
+static bool ceph_crypt_empty_dir(struct inode *inode)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+
+ return ci->i_rsubdirs + ci->i_rfiles == 1;
+}
+
+static struct fscrypt_operations ceph_fscrypt_ops = {
+ .get_context = ceph_crypt_get_context,
+ .set_context = ceph_crypt_set_context,
+ .empty_dir = ceph_crypt_empty_dir,
+ .max_namelen = NAME_MAX,
+};
+
+void ceph_fscrypt_set_ops(struct super_block *sb)
+{
+ fscrypt_set_ops(sb, &ceph_fscrypt_ops);
+}
diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
new file mode 100644
index 000000000000..189bd8424284
--- /dev/null
+++ b/fs/ceph/crypto.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Ceph fscrypt functionality
+ */
+
+#ifndef _CEPH_CRYPTO_H
+#define _CEPH_CRYPTO_H
+
+#include <linux/fscrypt.h>
+
+#define CEPH_XATTR_NAME_ENCRYPTION_CONTEXT "encryption.ctx"
+
+#ifdef CONFIG_FS_ENCRYPTION
+void ceph_fscrypt_set_ops(struct super_block *sb);
+
+#else /* CONFIG_FS_ENCRYPTION */
+
+static inline void ceph_fscrypt_set_ops(struct super_block *sb)
+{
+}
+
+#endif /* CONFIG_FS_ENCRYPTION */
+
+#endif
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 5d20a620e96c..d465ad48ade5 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -14,10 +14,12 @@
#include <linux/random.h>
#include <linux/sort.h>
#include <linux/iversion.h>
+#include <linux/fscrypt.h>

#include "super.h"
#include "mds_client.h"
#include "cache.h"
+#include "crypto.h"
#include <linux/ceph/decode.h>

/*
@@ -553,6 +555,7 @@ void ceph_evict_inode(struct inode *inode)
clear_inode(inode);

ceph_fscache_unregister_inode_cookie(ci);
+ fscrypt_put_encryption_info(inode);

__ceph_remove_caps(ci);

@@ -912,6 +915,9 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
ceph_forget_all_cached_acls(inode);
ceph_security_invalidate_secctx(inode);
xattr_blob = NULL;
+ if ((inode->i_state & I_NEW) &&
+ ceph_inode_has_xattr(ci, CEPH_XATTR_NAME_ENCRYPTION_CONTEXT))
+ inode_set_flags(inode, S_ENCRYPTED, S_ENCRYPTED);
}

/* finally update i_version */
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 9b1b7f4cfdd4..cdac6ff675e2 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -20,6 +20,7 @@
#include "super.h"
#include "mds_client.h"
#include "cache.h"
+#include "crypto.h"

#include <linux/ceph/ceph_features.h>
#include <linux/ceph/decode.h>
@@ -988,6 +989,8 @@ static int ceph_set_super(struct super_block *s, struct fs_context *fc)
s->s_time_min = 0;
s->s_time_max = U32_MAX;

+ ceph_fscrypt_set_ops(s);
+
ret = set_anon_super_fc(s, fc);
if (ret != 0)
fsc->sb = NULL;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 13b02887b085..efe2e963c631 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1013,6 +1013,7 @@ extern ssize_t ceph_listxattr(struct dentry *, char *, size_t);
extern struct ceph_buffer *__ceph_build_xattrs_blob(struct ceph_inode_info *ci);
extern void __ceph_destroy_xattrs(struct ceph_inode_info *ci);
extern const struct xattr_handler *ceph_xattr_handlers[];
+bool ceph_inode_has_xattr(struct ceph_inode_info *ci, const char *name);

struct ceph_acl_sec_ctx {
#ifdef CONFIG_CEPH_FS_POSIX_ACL
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 24997982de01..d0d719b768e4 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -1359,6 +1359,38 @@ void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx)
ceph_pagelist_release(as_ctx->pagelist);
}

+/* Return true if inode's xattr blob has an xattr named "name" */
+bool ceph_inode_has_xattr(struct ceph_inode_info *ci, const char *name)
+{
+ void *p, *end;
+ u32 numattr;
+ size_t namelen;
+
+ lockdep_assert_held(&ci->i_ceph_lock);
+
+ if (!ci->i_xattrs.blob || ci->i_xattrs.blob->vec.iov_len <= 4)
+ return false;
+
+ namelen = strlen(name);
+ p = ci->i_xattrs.blob->vec.iov_base;
+ end = p + ci->i_xattrs.blob->vec.iov_len;
+ ceph_decode_32_safe(&p, end, numattr, bad);
+
+ while (numattr--) {
+ u32 len;
+
+ ceph_decode_32_safe(&p, end, len, bad);
+ ceph_decode_need(&p, end, len, bad);
+ if (len == namelen && !memcmp(p, name, len))
+ return true;
+ p += len;
+ ceph_decode_32_safe(&p, end, len, bad);
+ ceph_decode_skip_n(&p, end, len, bad);
+ }
+bad:
+ return false;
+}
+
/*
* List of handlers for synthetic system.* attributes. Other
* attributes are handled directly.
--
2.29.2