[RFC PATCH v3 10/16] ceph: add routine to create context prior to RPC

Jeff Layton
2020-09-14T19:18:57Z

After pre-creating a new inode, do an fscrypt prepare on it, fetch a
new encryption context and then marshal that into the security context
to be sent along with the RPC.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/crypto.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/ceph/crypto.h | 8 +++++++
fs/ceph/inode.c | 10 ++++++--
fs/ceph/super.h | 3 +++
4 files changed, 80 insertions(+), 2 deletions(-)

diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
index 879d9a0d3751..f037a4939026 100644
--- a/fs/ceph/crypto.c
+++ b/fs/ceph/crypto.c
@@ -46,3 +46,64 @@ void ceph_fscrypt_set_ops(struct super_block *sb)
{
fscrypt_set_ops(sb, &ceph_fscrypt_ops);
}
+
+int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
+ struct ceph_acl_sec_ctx *as)
+{
+ int ret, ctxsize;
+ size_t name_len;
+ char *name;
+ struct ceph_pagelist *pagelist = as->pagelist;
+ bool encrypted = false;
+
+ ret = fscrypt_prepare_new_inode(dir, inode, &encrypted);
+ if (ret)
+ return ret;
+ if (!encrypted)
+ return 0;
+
+ inode->i_flags |= S_ENCRYPTED;
+
+ ctxsize = fscrypt_context_for_new_inode(&as->fscrypt, inode);
+ if (ctxsize < 0)
+ return ctxsize;
+
+ /* marshal it in page array */
+ if (!pagelist) {
+ pagelist = ceph_pagelist_alloc(GFP_KERNEL);
+ if (!pagelist)
+ return -ENOMEM;
+ ret = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
+ if (ret)
+ goto out;
+ ceph_pagelist_encode_32(pagelist, 1);
+ }
+
+ name = CEPH_XATTR_NAME_ENCRYPTION_CONTEXT;
+ name_len = strlen(name);
+ ret = ceph_pagelist_reserve(pagelist, 4 * 2 + name_len + ctxsize);
+ if (ret)
+ goto out;
+
+ if (as->pagelist) {
+ BUG_ON(pagelist->length <= sizeof(__le32));
+ if (list_is_singular(&pagelist->head)) {
+ le32_add_cpu((__le32*)pagelist->mapped_tail, 1);
+ } else {
+ struct page *page = list_first_entry(&pagelist->head,
+ struct page, lru);
+ void *addr = kmap_atomic(page);
+ le32_add_cpu((__le32*)addr, 1);
+ kunmap_atomic(addr);
+ }
+ }
+
+ ceph_pagelist_encode_32(pagelist, name_len);
+ ceph_pagelist_append(pagelist, name, name_len);
+ ceph_pagelist_encode_32(pagelist, ctxsize);
+ ceph_pagelist_append(pagelist, as->fscrypt, ctxsize);
+out:
+ if (pagelist && !as->pagelist)
+ ceph_pagelist_release(pagelist);
+ return ret;
+}
diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
index b5f38ee80553..c1b6ec4b2961 100644
--- a/fs/ceph/crypto.h
+++ b/fs/ceph/crypto.h
@@ -11,6 +11,8 @@
#define CEPH_XATTR_NAME_ENCRYPTION_CONTEXT "encryption.ctx"

void ceph_fscrypt_set_ops(struct super_block *sb);
+int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
+ struct ceph_acl_sec_ctx *as);

#else /* CONFIG_FS_ENCRYPTION */

@@ -19,6 +21,12 @@ static inline int ceph_fscrypt_set_ops(struct super_block *sb)
return 0;
}

+static inline int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
+ struct ceph_acl_sec_ctx *as)
+{
+ return 0;
+}
+
#endif /* CONFIG_FS_ENCRYPTION */

#endif
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index f50e7873bf6e..2fda08518312 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -18,6 +18,7 @@
#include "super.h"
#include "mds_client.h"
#include "cache.h"
+#include "crypto.h"
#include <linux/ceph/decode.h>

/*
@@ -73,12 +74,17 @@ struct inode *ceph_new_inode(struct inode *dir, struct dentry *dentry,
goto out_err;
}

+ inode->i_state = 0;
+ inode->i_mode = *mode;
+
err = ceph_security_init_secctx(dentry, *mode, as_ctx);
if (err < 0)
goto out_err;

- inode->i_state = 0;
- inode->i_mode = *mode;
+ err = ceph_fscrypt_prepare_context(dir, inode, as_ctx);
+ if (err)
+ goto out_err;
+
return inode;
out_err:
iput(inode);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index c05ed00035ec..5d5283552c03 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1003,6 +1003,9 @@ struct ceph_acl_sec_ctx {
#ifdef CONFIG_CEPH_FS_SECURITY_LABEL
void *sec_ctx;
u32 sec_ctxlen;
+#endif
+#ifdef CONFIG_FS_ENCRYPTION
+ u8 fscrypt[FSCRYPT_SET_CONTEXT_MAX_SIZE];
#endif
struct ceph_pagelist *pagelist;
};
--
2.26.2