@@ -1531,25 +1531,29 @@ static void ll_qos_mkdir_prep(struct md_op_data *op_data, struct inode *dir)
up_read(&rlli->lli_lsm_sem);
}
-static int ll_new_node(struct inode *dir, struct dentry *dentry,
- const char *tgt, umode_t mode, int rdev,
+static int ll_new_node(struct inode *dir, struct dentry *dchild,
+ const char *tgt, umode_t mode, u64 rdev,
u32 opc)
{
+ struct qstr *name = &dchild->d_name;
struct ptlrpc_request *request = NULL;
struct md_op_data *op_data = NULL;
struct inode *inode = NULL;
struct ll_sb_info *sbi = ll_i2sbi(dir);
- int tgt_len = 0;
+ struct fscrypt_str *disk_link = NULL;
bool encrypt = false;
int err;
- if (unlikely(tgt))
- tgt_len = strlen(tgt) + 1;
+ if (unlikely(tgt)) {
+ disk_link = (struct fscrypt_str *)rdev;
+ rdev = 0;
+ if (!disk_link)
+ return -EINVAL;
+ }
+
again:
- op_data = ll_prep_md_op_data(NULL, dir, NULL,
- dentry->d_name.name,
- dentry->d_name.len,
- 0, opc, NULL);
+ op_data = ll_prep_md_op_data(NULL, dir, NULL, name->name,
+ name->len, 0, opc, NULL);
if (IS_ERR(op_data)) {
err = PTR_ERR(op_data);
goto err_exit;
@@ -1559,7 +1563,7 @@ static int ll_new_node(struct inode *dir, struct dentry *dentry,
ll_qos_mkdir_prep(op_data, dir);
if (sbi->ll_flags & LL_SBI_FILE_SECCTX) {
- err = ll_dentry_init_security(dentry, mode, &dentry->d_name,
+ err = ll_dentry_init_security(dchild, mode, &dchild->d_name,
&op_data->op_file_secctx_name,
&op_data->op_file_secctx,
&op_data->op_file_secctx_size);
@@ -1585,9 +1589,40 @@ static int ll_new_node(struct inode *dir, struct dentry *dentry,
err = fscrypt_inherit_context(dir, NULL, op_data, false);
if (err)
goto err_exit;
+
+ if (S_ISLNK(mode)) {
+ /* fscrypt needs inode to encrypt target name, so create
+ * a fake inode and associate encryption context got
+ * from fscrypt_inherit_context.
+ */
+ struct inode *fakeinode =
+ dchild->d_sb->s_op->alloc_inode(dchild->d_sb);
+
+ if (!fakeinode) {
+ err = -ENOMEM;
+ goto err_exit;
+ }
+ fakeinode->i_sb = dchild->d_sb;
+ fakeinode->i_mode |= S_IFLNK;
+ err = ll_set_encflags(fakeinode,
+ op_data->op_file_encctx,
+ op_data->op_file_encctx_size,
+ true);
+ if (!err)
+ err = __fscrypt_encrypt_symlink(fakeinode, tgt,
+ strlen(tgt),
+ disk_link);
+
+ ll_xattr_cache_destroy(fakeinode);
+ fscrypt_put_encryption_info(fakeinode);
+ dchild->d_sb->s_op->destroy_inode(fakeinode);
+ if (err)
+ goto err_exit;
+ }
}
- err = md_create(sbi->ll_md_exp, op_data, tgt, tgt_len, mode,
+ err = md_create(sbi->ll_md_exp, op_data, tgt ? disk_link->name : NULL,
+ tgt ? disk_link->len : 0, mode,
from_kuid(&init_user_ns, current_fsuid()),
from_kgid(&init_user_ns, current_fsgid()),
current_cap(), rdev, &request);
@@ -1687,16 +1722,32 @@ static int ll_new_node(struct inode *dir, struct dentry *dentry,
goto err_exit;
}
- d_instantiate(dentry, inode);
+ d_instantiate(dchild, inode);
if (encrypt) {
err = fscrypt_inherit_context(dir, inode, NULL, true);
if (err)
goto err_exit;
+
+ if (S_ISLNK(mode)) {
+ struct ll_inode_info *lli = ll_i2info(inode);
+
+ /* Cache the plaintext symlink target
+ * for later use by get_link()
+ */
+ lli->lli_symlink_name = kzalloc(strlen(tgt) + 1,
+ GFP_NOFS);
+ /* do not return an error if we cannot
+ * cache the symlink locally
+ */
+ if (lli->lli_symlink_name)
+ memcpy(lli->lli_symlink_name,
+ tgt, strlen(tgt) + 1);
+ }
}
if (!(sbi->ll_flags & LL_SBI_FILE_SECCTX))
- err = ll_inode_init_security(dentry, inode, dir);
+ err = ll_inode_init_security(dchild, inode, dir);
err_exit:
if (request)
ptlrpc_req_finished(request);
@@ -1894,17 +1945,27 @@ static int ll_rmdir(struct inode *dir, struct dentry *dchild)
return rc;
}
-static int ll_symlink(struct inode *dir, struct dentry *dentry,
- const char *oldname)
+static int ll_symlink(struct inode *dir, struct dentry *dchild,
+ const char *oldpath)
{
ktime_t kstart = ktime_get();
+ int len = strlen(oldpath);
+ struct fscrypt_str disk_link;
int err;
CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir=" DFID "(%p),target=%.*s\n",
- dentry, PFID(ll_inode2fid(dir)), dir, 3000, oldname);
+ dchild, PFID(ll_inode2fid(dir)), dir, 3000, oldpath);
+
+ err = fscrypt_prepare_symlink(dir, oldpath, len, dir->i_sb->s_blocksize,
+ &disk_link);
+ if (err)
+ return err;
+
+ err = ll_new_node(dir, dchild, oldpath, S_IFLNK | 0777,
+ (u64)&disk_link, LUSTRE_OPC_SYMLINK);
- err = ll_new_node(dir, dentry, oldname, S_IFLNK | 0777,
- 0, LUSTRE_OPC_SYMLINK);
+ if (disk_link.name != (unsigned char *)oldpath)
+ kfree(disk_link.name);
if (!err)
ll_stats_ops_tally(ll_i2sbi(dir), LPROC_LL_SYMLINK,
@@ -38,8 +38,13 @@
#include "llite_internal.h"
/* Must be called with lli_size_mutex locked */
+/* HAVE_IOP_GET_LINK is defined from kernel 4.5, whereas
+ * IS_ENCRYPTED is brought by kernel 4.14.
+ * So there is no need to handle encryption case otherwise.
+ */
static int ll_readlink_internal(struct inode *inode,
- struct ptlrpc_request **request, char **symname)
+ struct ptlrpc_request **request,
+ char **symname, struct delayed_call *done)
{
struct ll_inode_info *lli = ll_i2info(inode);
struct ll_sb_info *sbi = ll_i2sbi(inode);
@@ -97,7 +102,9 @@ static int ll_readlink_internal(struct inode *inode,
}
*symname = req_capsule_server_get(&(*request)->rq_pill, &RMF_MDT_MD);
- if (!*symname || strnlen(*symname, symlen) != symlen - 1) {
+ if (!*symname ||
+ (!IS_ENCRYPTED(inode) &&
+ strnlen(*symname, symlen) != symlen - 1)) {
/* not full/NULL terminated */
CERROR("%s: inode " DFID ": symlink not NULL terminated string of length %d\n",
ll_i2sbi(inode)->ll_fsname,
@@ -106,6 +113,21 @@ static int ll_readlink_internal(struct inode *inode,
goto failed;
}
+ if (IS_ENCRYPTED(inode)) {
+ const char *target = fscrypt_get_symlink(inode, *symname,
+ symlen, done);
+ if (IS_ERR(target))
+ return PTR_ERR(target);
+ symlen = strlen(target) + 1;
+ *symname = (char *)target;
+
+ /* Do not cache symlink targets encoded without the key,
+ * since those become outdated once the key is added.
+ */
+ if (!fscrypt_has_encryption_key(inode))
+ return 0;
+ }
+
lli->lli_symlink_name = kzalloc(symlen, GFP_NOFS);
/* do not return an error if we cannot cache the symlink locally */
if (lli->lli_symlink_name) {
@@ -131,12 +153,12 @@ static const char *ll_get_link(struct dentry *dentry,
int rc;
char *symname = NULL;
+ CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, inode="DFID"(%p)\n",
+ dentry, PFID(ll_inode2fid(inode)), inode);
if (!dentry)
return ERR_PTR(-ECHILD);
-
- CDEBUG(D_VFSTRACE, "VFS Op\n");
ll_inode_size_lock(inode);
- rc = ll_readlink_internal(inode, &request, &symname);
+ rc = ll_readlink_internal(inode, &request, &symname, done);
ll_inode_size_unlock(inode);
if (rc) {
ptlrpc_req_finished(request);
@@ -151,10 +173,61 @@ static const char *ll_get_link(struct dentry *dentry,
return symname;
}
+/**
+ * ll_getattr_link() - link-specific getattr to set the correct st_size
+ * for encrypted symlinks
+ *
+ * Override st_size of encrypted symlinks to be the length of the decrypted
+ * symlink target (or the no-key encoded symlink target, if the key is
+ * unavailable) rather than the length of the encrypted symlink target. This is
+ * necessary for st_size to match the symlink target that userspace actually
+ * sees. POSIX requires this, and some userspace programs depend on it.
+ *
+ * For non encrypted symlinks, this is a just calling ll_getattr().
+ * For encrypted symlinks, this additionally requires reading the symlink target
+ * from disk if needed, setting up the inode's encryption key if possible, and
+ * then decrypting or encoding the symlink target. This makes lstat() more
+ * heavyweight than is normally the case. However, decrypted symlink targets
+ * will be cached in ->i_link, so usually the symlink won't have to be read and
+ * decrypted again later if/when it is actually followed, readlink() is called,
+ * or lstat() is called again.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int ll_getattr_link(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int flags)
+{
+ struct dentry *dentry = path->dentry;
+ struct inode *inode = d_inode(dentry);
+ DEFINE_DELAYED_CALL(done);
+ const char *link;
+ int rc;
+
+ rc = ll_getattr(path, stat, request_mask, flags);
+ if (rc || !IS_ENCRYPTED(inode))
+ return rc;
+
+ /*
+ * To get the symlink target that userspace will see (whether it's the
+ * decrypted target or the no-key encoded target), we can just get it
+ * in the same way the VFS does during path resolution and readlink().
+ */
+ link = READ_ONCE(inode->i_link);
+ if (!link) {
+ link = inode->i_op->get_link(dentry, inode, &done);
+ if (IS_ERR(link))
+ return PTR_ERR(link);
+ }
+ stat->size = strlen(link);
+ do_delayed_call(&done);
+ return 0;
+}
+
+
const struct inode_operations ll_fast_symlink_inode_operations = {
.setattr = ll_setattr,
.get_link = ll_get_link,
- .getattr = ll_getattr,
+ .getattr = ll_getattr_link,
.permission = ll_inode_permission,
.listxattr = ll_listxattr,
};