When creating symlinks in encrypted directories, encrypt and
base64-encode the target with the new inode's key before sending to the
MDS.
When filling a symlinked inode, base64-decode it into a buffer that
we'll keep in ci->i_symlink. When get_link is called, decrypt the buffer
into a new one that will hang off i_link.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/ceph/dir.c | 32 ++++++++++++++++---
fs/ceph/inode.c | 82 +++++++++++++++++++++++++++++++++++++++----------
fs/ceph/super.h | 3 ++
3 files changed, 96 insertions(+), 21 deletions(-)
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 0ba17c592fe1..7ff8921dd3a7 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -948,6 +948,7 @@ static int ceph_symlink(struct inode *dir, struct dentry *dentry,
struct ceph_mds_client *mdsc = fsc->mdsc;
struct ceph_mds_request *req;
struct ceph_acl_sec_ctx as_ctx = {};
+ struct fscrypt_str osd_link = FSTR_INIT(NULL, 0);
umode_t mode = S_IFLNK | 0777;
int err;
@@ -973,11 +974,33 @@ static int ceph_symlink(struct inode *dir, struct dentry *dentry,
goto out_req;
}
- req->r_path2 = kstrdup(dest, GFP_KERNEL);
- if (!req->r_path2) {
- err = -ENOMEM;
- goto out_req;
+ if (IS_ENCRYPTED(req->r_new_inode)) {
+ int len = strlen(dest);
+
+ err = fscrypt_prepare_symlink(dir, dest, len, PATH_MAX, &osd_link);
+ if (err)
+ goto out_req;
+
+ err = fscrypt_encrypt_symlink(req->r_new_inode, dest, len, &osd_link);
+ if (err)
+ goto out_req;
+
+ req->r_path2 = kmalloc(BASE64_CHARS(osd_link.len) + 1, GFP_KERNEL);
+ if (!req->r_path2) {
+ err = -ENOMEM;
+ goto out_req;
+ }
+
+ len = base64_encode_fname(osd_link.name, osd_link.len, req->r_path2);
+ req->r_path2[len] = '\0';
+ } else {
+ req->r_path2 = kstrdup(dest, GFP_KERNEL);
+ if (!req->r_path2) {
+ err = -ENOMEM;
+ goto out_req;
+ }
}
+
req->r_parent = dir;
set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
req->r_dentry = dget(dentry);
@@ -997,6 +1020,7 @@ static int ceph_symlink(struct inode *dir, struct dentry *dentry,
if (err)
d_drop(dentry);
ceph_release_acl_sec_ctx(&as_ctx);
+ fscrypt_fname_free_buffer(&osd_link);
return err;
}
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index e578e4cdcf30..dd39f886b03c 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -14,6 +14,7 @@
#include <linux/random.h>
#include <linux/sort.h>
#include <linux/iversion.h>
+#include <linux/base64_fname.h>
#include "super.h"
#include "mds_client.h"
@@ -33,8 +34,6 @@
* (typically because they are in the message handler path).
*/
-static const struct inode_operations ceph_symlink_iops;
-
static void ceph_inode_work(struct work_struct *work);
/*
@@ -503,6 +502,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
atomic64_set(&ci->i_complete_seq[0], 0);
atomic64_set(&ci->i_complete_seq[1], 0);
ci->i_symlink = NULL;
+ ci->i_symlink_len = 0;
ci->i_max_bytes = 0;
ci->i_max_files = 0;
@@ -590,6 +590,7 @@ void ceph_free_inode(struct inode *inode)
struct ceph_inode_info *ci = ceph_inode(inode);
kfree(ci->i_symlink);
+ fscrypt_free_inode(inode);
kmem_cache_free(ceph_inode_cachep, ci);
}
@@ -991,34 +992,60 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
inode->i_fop = &ceph_file_fops;
break;
case S_IFLNK:
- inode->i_op = &ceph_symlink_iops;
if (!ci->i_symlink) {
u32 symlen = iinfo->symlink_len;
char *sym;
spin_unlock(&ci->i_ceph_lock);
- if (symlen != i_size_read(inode)) {
- pr_err("%s %llx.%llx BAD symlink "
- "size %lld\n", __func__,
- ceph_vinop(inode),
- i_size_read(inode));
+ if (IS_ENCRYPTED(inode)) {
+ /* Do base64 decode so that we get the right size (maybe?) */
+ err = -ENOMEM;
+ sym = kmalloc(symlen + 1, GFP_NOFS);
+ if (!sym)
+ goto out;
+
+ symlen = base64_decode_fname(iinfo->symlink, symlen, sym);
+ /*
+ * i_size as reported by the MDS may be wrong, due to base64
+ * inflation and padding. Fix it up here.
+ */
i_size_write(inode, symlen);
inode->i_blocks = calc_inode_blocks(symlen);
- }
+ } else {
+ if (symlen != i_size_read(inode)) {
+ pr_err("%s %llx.%llx BAD symlink size %lld\n",
+ __func__, ceph_vinop(inode), i_size_read(inode));
+ i_size_write(inode, symlen);
+ inode->i_blocks = calc_inode_blocks(symlen);
+ }
- err = -ENOMEM;
- sym = kstrndup(iinfo->symlink, symlen, GFP_NOFS);
- if (!sym)
- goto out;
+ err = -ENOMEM;
+ sym = kstrndup(iinfo->symlink, symlen, GFP_NOFS);
+ if (!sym)
+ goto out;
+ }
spin_lock(&ci->i_ceph_lock);
- if (!ci->i_symlink)
+ if (!ci->i_symlink) {
ci->i_symlink = sym;
- else
+ ci->i_symlink_len = symlen;
+ } else {
kfree(sym); /* lost a race */
+ }
+ }
+
+ if (IS_ENCRYPTED(inode)) {
+ /*
+ * Encrypted symlinks need to be decrypted before we can
+ * cache their targets in i_link. Leave it blank for now.
+ */
+ inode->i_link = NULL;
+ inode->i_op = &ceph_encrypted_symlink_iops;
+ } else {
+ inode->i_link = ci->i_symlink;
+ inode->i_op = &ceph_symlink_iops;
}
- inode->i_link = ci->i_symlink;
break;
case S_IFDIR:
inode->i_op = &ceph_dir_iops;
@@ -2123,16 +2150,37 @@ static void ceph_inode_work(struct work_struct *work)
iput(inode);
}
+static const char *ceph_encrypted_get_link(struct dentry *dentry, struct inode *inode,
+ struct delayed_call *done)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+
+ if (inode->i_link)
+ return inode->i_link;
+
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
+ return fscrypt_get_symlink(inode, ci->i_symlink, ci->i_symlink_len, done);
+}
+
/*
* symlinks
*/
-static const struct inode_operations ceph_symlink_iops = {
+const struct inode_operations ceph_symlink_iops = {
.get_link = simple_get_link,
.setattr = ceph_setattr,
.getattr = ceph_getattr,
.listxattr = ceph_listxattr,
};
+const struct inode_operations ceph_encrypted_symlink_iops = {
+ .get_link = ceph_encrypted_get_link,
+ .setattr = ceph_setattr,
+ .getattr = ceph_getattr,
+ .listxattr = ceph_listxattr,
+};
+
int __ceph_setattr(struct inode *inode, struct iattr *attr)
{
struct ceph_inode_info *ci = ceph_inode(inode);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 7c859824f64c..eea0ee17b747 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -344,6 +344,7 @@ struct ceph_inode_info {
u64 i_max_bytes, i_max_files;
s32 i_dir_pin;
+ u32 i_symlink_len;
struct rb_root i_fragtree;
int i_fragtree_nsplits;
@@ -932,6 +933,8 @@ struct ceph_mds_reply_dirfrag;
struct ceph_acl_sec_ctx;
extern const struct inode_operations ceph_file_iops;
+extern const struct inode_operations ceph_symlink_iops;
+extern const struct inode_operations ceph_encrypted_symlink_iops;
extern struct inode *ceph_alloc_inode(struct super_block *sb);
extern void ceph_evict_inode(struct inode *inode);
--
2.26.2
