[RFC PATCH v11 06/51] ceph: crypto context handling for ceph

Jeff Layton
2022-03-22T14:18:33Z

Have set_context do a setattr that sets the fscrypt_auth value, and
get_context just return the contents of that field.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/Makefile | 1 +
fs/ceph/crypto.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/ceph/crypto.h | 29 ++++++++++++++++++
fs/ceph/inode.c | 3 ++
fs/ceph/super.c | 3 ++
5 files changed, 112 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..a513ff373b13
--- /dev/null
+++ b/fs/ceph/crypto.c
@@ -0,0 +1,76 @@
+// 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)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_fscrypt_auth *cfa = (struct ceph_fscrypt_auth *)ci->fscrypt_auth;
+ u32 ctxlen;
+
+ /* Non existent or too short? */
+ if (!cfa || (ci->fscrypt_auth_len < (offsetof(struct ceph_fscrypt_auth, cfa_blob) + 1)))
+ return -ENOBUFS;
+
+ /* Some format we don't recognize? */
+ if (le32_to_cpu(cfa->cfa_version) != CEPH_FSCRYPT_AUTH_VERSION)
+ return -ENOBUFS;
+
+ ctxlen = le32_to_cpu(cfa->cfa_blob_len);
+ if (len < ctxlen)
+ return -ERANGE;
+
+ memcpy(ctx, cfa->cfa_blob, ctxlen);
+ return ctxlen;
+}
+
+static int ceph_crypt_set_context(struct inode *inode, const void *ctx, size_t len, void *fs_data)
+{
+ int ret;
+ struct iattr attr = { };
+ struct ceph_iattr cia = { };
+ struct ceph_fscrypt_auth *cfa;
+
+ WARN_ON_ONCE(fs_data);
+
+ if (len > FSCRYPT_SET_CONTEXT_MAX_SIZE)
+ return -EINVAL;
+
+ cfa = kzalloc(sizeof(*cfa), GFP_KERNEL);
+ if (!cfa)
+ return -ENOMEM;
+
+ cfa->cfa_version = cpu_to_le32(CEPH_FSCRYPT_AUTH_VERSION);
+ cfa->cfa_blob_len = cpu_to_le32(len);
+ memcpy(cfa->cfa_blob, ctx, len);
+
+ cia.fscrypt_auth = cfa;
+
+ ret = __ceph_setattr(inode, &attr, &cia);
+ if (ret == 0)
+ inode_set_flags(inode, S_ENCRYPTED, S_ENCRYPTED);
+ kfree(cia.fscrypt_auth);
+ 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,
+};
+
+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..6c3831c57c8d
--- /dev/null
+++ b/fs/ceph/crypto.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Ceph fscrypt functionality
+ */
+
+#ifndef _CEPH_CRYPTO_H
+#define _CEPH_CRYPTO_H
+
+#include <linux/fscrypt.h>
+
+struct ceph_fscrypt_auth {
+ __le32 cfa_version;
+ __le32 cfa_blob_len;
+ u8 cfa_blob[FSCRYPT_SET_CONTEXT_MAX_SIZE];
+} __packed;
+
+#ifdef CONFIG_FS_ENCRYPTION
+#define CEPH_FSCRYPT_AUTH_VERSION 1
+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 7547b7de170f..2e0e321a58cb 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>

/*
@@ -644,6 +646,7 @@ 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);

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index a859921bbe96..52ff78f0462a 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>
@@ -1128,6 +1129,8 @@ 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;
--
2.35.1