Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index 926e5df..bb3b7fc 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -1,10 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/crypto/hooks.c
*
* Encryption hooks for higher-level filesystem operations.
*/
-#include <linux/ratelimit.h>
#include "fscrypt_private.h"
/**
@@ -39,9 +39,9 @@
dir = dget_parent(file_dentry(filp));
if (IS_ENCRYPTED(d_inode(dir)) &&
!fscrypt_has_permitted_context(d_inode(dir), inode)) {
- fscrypt_warn(inode->i_sb,
- "inconsistent encryption contexts: %lu/%lu",
- d_inode(dir)->i_ino, inode->i_ino);
+ fscrypt_warn(inode,
+ "Inconsistent encryption context (parent directory: %lu)",
+ d_inode(dir)->i_ino);
err = -EPERM;
}
dput(dir);
@@ -49,7 +49,8 @@
}
EXPORT_SYMBOL_GPL(fscrypt_file_open);
-int __fscrypt_prepare_link(struct inode *inode, struct inode *dir)
+int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
+ struct dentry *dentry)
{
int err;
@@ -57,8 +58,12 @@
if (err)
return err;
+ /* ... in case we looked up ciphertext name before key was added */
+ if (dentry->d_flags & DCACHE_ENCRYPTED_NAME)
+ return -ENOKEY;
+
if (!fscrypt_has_permitted_context(dir, inode))
- return -EPERM;
+ return -EXDEV;
return 0;
}
@@ -78,37 +83,42 @@
if (err)
return err;
+ /* ... in case we looked up ciphertext name(s) before key was added */
+ if ((old_dentry->d_flags | new_dentry->d_flags) &
+ DCACHE_ENCRYPTED_NAME)
+ return -ENOKEY;
+
if (old_dir != new_dir) {
if (IS_ENCRYPTED(new_dir) &&
!fscrypt_has_permitted_context(new_dir,
d_inode(old_dentry)))
- return -EPERM;
+ return -EXDEV;
if ((flags & RENAME_EXCHANGE) &&
IS_ENCRYPTED(old_dir) &&
!fscrypt_has_permitted_context(old_dir,
d_inode(new_dentry)))
- return -EPERM;
+ return -EXDEV;
}
return 0;
}
EXPORT_SYMBOL_GPL(__fscrypt_prepare_rename);
-int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry)
+int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
+ struct fscrypt_name *fname)
{
- int err = fscrypt_get_encryption_info(dir);
+ int err = fscrypt_setup_filename(dir, &dentry->d_name, 1, fname);
- if (err)
+ if (err && err != -ENOENT)
return err;
- if (fscrypt_has_encryption_key(dir)) {
+ if (fname->is_ciphertext_name) {
spin_lock(&dentry->d_lock);
- dentry->d_flags |= DCACHE_ENCRYPTED_WITH_KEY;
+ dentry->d_flags |= DCACHE_ENCRYPTED_NAME;
spin_unlock(&dentry->d_lock);
+ d_set_d_op(dentry, &fscrypt_d_ops);
}
-
- d_set_d_op(dentry, &fscrypt_d_ops);
- return 0;
+ return err;
}
EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup);
@@ -179,11 +189,9 @@
sd->len = cpu_to_le16(ciphertext_len);
err = fname_encrypt(inode, &iname, sd->encrypted_path, ciphertext_len);
- if (err) {
- if (!disk_link->name)
- kfree(sd);
- return err;
- }
+ if (err)
+ goto err_free_sd;
+
/*
* Null-terminating the ciphertext doesn't make sense, but we still
* count the null terminator in the length, so we might as well
@@ -191,9 +199,20 @@
*/
sd->encrypted_path[ciphertext_len] = '\0';
+ /* Cache the plaintext symlink target for later use by get_link() */
+ err = -ENOMEM;
+ inode->i_link = kmemdup(target, len + 1, GFP_NOFS);
+ if (!inode->i_link)
+ goto err_free_sd;
+
if (!disk_link->name)
disk_link->name = (unsigned char *)sd;
return 0;
+
+err_free_sd:
+ if (!disk_link->name)
+ kfree(sd);
+ return err;
}
EXPORT_SYMBOL_GPL(__fscrypt_encrypt_symlink);
@@ -202,7 +221,7 @@
* @inode: the symlink inode
* @caddr: the on-disk contents of the symlink
* @max_size: size of @caddr buffer
- * @done: if successful, will be set up to free the returned target
+ * @done: if successful, will be set up to free the returned target if needed
*
* If the symlink's encryption key is available, we decrypt its target.
* Otherwise, we encode its target for presentation.
@@ -217,12 +236,18 @@
{
const struct fscrypt_symlink_data *sd;
struct fscrypt_str cstr, pstr;
+ bool has_key;
int err;
/* This is for encrypted symlinks only */
if (WARN_ON(!IS_ENCRYPTED(inode)))
return ERR_PTR(-EINVAL);
+ /* If the decrypted target is already cached, just return it. */
+ pstr.name = READ_ONCE(inode->i_link);
+ if (pstr.name)
+ return pstr.name;
+
/*
* Try to set up the symlink's encryption key, but we can continue
* regardless of whether the key is available or not.
@@ -230,6 +255,7 @@
err = fscrypt_get_encryption_info(inode);
if (err)
return ERR_PTR(err);
+ has_key = fscrypt_has_encryption_key(inode);
/*
* For historical reasons, encrypted symlink targets are prefixed with
@@ -261,7 +287,17 @@
goto err_kfree;
pstr.name[pstr.len] = '\0';
- set_delayed_call(done, kfree_link, pstr.name);
+
+ /*
+ * Cache decrypted symlink targets in i_link for later use. Don't cache
+ * symlink targets encoded without the key, since those become outdated
+ * once the key is added. This pairs with the READ_ONCE() above and in
+ * the VFS path lookup code.
+ */
+ if (!has_key ||
+ cmpxchg_release(&inode->i_link, NULL, pstr.name) != NULL)
+ set_delayed_call(done, kfree_link, pstr.name);
+
return pstr.name;
err_kfree: