@@ -572,6 +572,9 @@ int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key);
int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
const struct fscrypt_master_key *mk);
+void fscrypt_hash_inode_number(struct fscrypt_info *ci,
+ const struct fscrypt_master_key *mk);
+
/* keysetup_v1.c */
void fscrypt_put_direct_key(struct fscrypt_direct_key *dk);
@@ -10,6 +10,7 @@
#include <crypto/skcipher.h>
#include <linux/key.h>
+#include <linux/random.h>
#include "fscrypt_private.h"
@@ -222,6 +223,16 @@ int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
return 0;
}
+void fscrypt_hash_inode_number(struct fscrypt_info *ci,
+ const struct fscrypt_master_key *mk)
+{
+ WARN_ON(ci->ci_inode->i_ino == 0);
+ WARN_ON(!mk->mk_ino_hash_key_initialized);
+
+ ci->ci_hashed_ino = (u32)siphash_1u64(ci->ci_inode->i_ino,
+ &mk->mk_ino_hash_key);
+}
+
static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci,
struct fscrypt_master_key *mk)
{
@@ -254,8 +265,14 @@ static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci,
return err;
}
- ci->ci_hashed_ino = (u32)siphash_1u64(ci->ci_inode->i_ino,
- &mk->mk_ino_hash_key);
+ /*
+ * New inodes may not have an inode number assigned yet.
+ * Hashing their inode number is delayed until later.
+ */
+ if (ci->ci_inode->i_ino == 0)
+ WARN_ON(!(ci->ci_inode->i_state & I_CREATING));
+ else
+ fscrypt_hash_inode_number(ci, mk);
return 0;
}
@@ -454,57 +471,27 @@ static void put_crypt_info(struct fscrypt_info *ci)
kmem_cache_free(fscrypt_info_cachep, ci);
}
-int fscrypt_get_encryption_info(struct inode *inode)
+static int
+fscrypt_setup_encryption_info(struct inode *inode,
+ const union fscrypt_policy *policy,
+ const u8 nonce[FSCRYPT_FILE_NONCE_SIZE])
{
struct fscrypt_info *crypt_info;
- union fscrypt_context ctx;
struct fscrypt_mode *mode;
struct key *master_key = NULL;
int res;
- if (fscrypt_has_encryption_key(inode))
- return 0;
-
res = fscrypt_initialize(inode->i_sb->s_cop->flags);
if (res)
return res;
- res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
- if (res < 0) {
- const union fscrypt_context *dummy_ctx =
- fscrypt_get_dummy_context(inode->i_sb);
-
- if (IS_ENCRYPTED(inode) || !dummy_ctx) {
- fscrypt_warn(inode,
- "Error %d getting encryption context",
- res);
- return res;
- }
- /* Fake up a context for an unencrypted directory */
- res = fscrypt_context_size(dummy_ctx);
- memcpy(&ctx, dummy_ctx, res);
- }
-
crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS);
if (!crypt_info)
return -ENOMEM;
crypt_info->ci_inode = inode;
-
- res = fscrypt_policy_from_context(&crypt_info->ci_policy, &ctx, res);
- if (res) {
- fscrypt_warn(inode,
- "Unrecognized or corrupt encryption context");
- goto out;
- }
-
- memcpy(crypt_info->ci_nonce, fscrypt_context_nonce(&ctx),
- FSCRYPT_FILE_NONCE_SIZE);
-
- if (!fscrypt_supported_policy(&crypt_info->ci_policy, inode)) {
- res = -EINVAL;
- goto out;
- }
+ crypt_info->ci_policy = *policy;
+ memcpy(crypt_info->ci_nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);
mode = select_encryption_mode(&crypt_info->ci_policy, inode);
if (IS_ERR(mode)) {
@@ -519,8 +506,8 @@ int fscrypt_get_encryption_info(struct inode *inode)
goto out;
/*
- * Multiple tasks may race to set ->i_crypt_info, so use
- * cmpxchg_release(). This pairs with the smp_load_acquire() in
+ * For existing inodes, multiple tasks may race to set ->i_crypt_info.
+ * So use cmpxchg_release(). This pairs with the smp_load_acquire() in
* fscrypt_get_info(). I.e., here we publish ->i_crypt_info with a
* RELEASE barrier so that other tasks can ACQUIRE it.
*/
@@ -555,8 +542,117 @@ int fscrypt_get_encryption_info(struct inode *inode)
put_crypt_info(crypt_info);
return res;
}
+
+/**
+ * fscrypt_get_encryption_info() - set up an inode's encryption key
+ * @inode: the inode to set up the key for
+ *
+ * Set up ->i_crypt_info, if it hasn't already been done.
+ *
+ * Note: unless ->i_crypt_info is already set, this isn't %GFP_NOFS-safe. So
+ * generally this shouldn't be called from within a filesystem transaction.
+ *
+ * Return: 0 if ->i_crypt_info was set or was already set, *or* if the
+ * encryption key is unavailable. (Use fscrypt_has_encryption_key() to
+ * distinguish these cases.) Also can return another -errno code.
+ */
+int fscrypt_get_encryption_info(struct inode *inode)
+{
+ int res;
+ union fscrypt_context ctx;
+ union fscrypt_policy policy;
+
+ if (fscrypt_has_encryption_key(inode))
+ return 0;
+
+ res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+ if (res < 0) {
+ const union fscrypt_context *dummy_ctx =
+ fscrypt_get_dummy_context(inode->i_sb);
+
+ if (IS_ENCRYPTED(inode) || !dummy_ctx) {
+ fscrypt_warn(inode,
+ "Error %d getting encryption context",
+ res);
+ return res;
+ }
+ /* Fake up a context for an unencrypted directory */
+ res = fscrypt_context_size(dummy_ctx);
+ memcpy(&ctx, dummy_ctx, res);
+ }
+
+ res = fscrypt_policy_from_context(&policy, &ctx, res);
+ if (res) {
+ fscrypt_warn(inode,
+ "Unrecognized or corrupt encryption context");
+ return res;
+ }
+
+ if (!fscrypt_supported_policy(&policy, inode))
+ return -EINVAL;
+
+ return fscrypt_setup_encryption_info(inode, &policy,
+ fscrypt_context_nonce(&ctx));
+}
EXPORT_SYMBOL(fscrypt_get_encryption_info);
+/**
+ * fscrypt_prepare_new_inode() - prepare to create a new inode in a directory
+ * @dir: a possibly-encrypted directory
+ * @inode: the new inode. ->i_mode must be set already.
+ * ->i_ino doesn't need to be set yet.
+ * @encrypt_ret: (output) set to %true if the new inode will be encrypted
+ *
+ * If the directory is encrypted, set up its ->i_crypt_info in preparation for
+ * encrypting the name of the new file. Also, if the new inode will be
+ * encrypted, set up its ->i_crypt_info and set *encrypt_ret=true.
+ *
+ * This isn't %GFP_NOFS-safe, and therefore it should be called before starting
+ * any filesystem transaction to create the inode. For this reason, ->i_ino
+ * isn't required to be set yet, as the filesystem may not have set it yet.
+ *
+ * This doesn't persist the new inode's encryption context. That still needs to
+ * be done later by calling fscrypt_set_context().
+ *
+ * Return: 0 on success, -ENOKEY if the directory's encryption key is missing,
+ * or another -errno code
+ */
+int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
+ bool *encrypt_ret)
+{
+ int err;
+ u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
+
+ if (!IS_ENCRYPTED(dir) && fscrypt_get_dummy_context(dir->i_sb) == NULL)
+ return 0;
+
+ err = fscrypt_get_encryption_info(dir);
+ if (err)
+ return err;
+ if (!fscrypt_has_encryption_key(dir))
+ return -ENOKEY;
+
+ if (WARN_ON_ONCE(inode->i_mode == 0))
+ return -EINVAL;
+
+ /*
+ * Only regular files, directories, and symlinks are encrypted.
+ * Special files like device nodes and named pipes aren't.
+ */
+ if (!S_ISREG(inode->i_mode) &&
+ !S_ISDIR(inode->i_mode) &&
+ !S_ISLNK(inode->i_mode))
+ return 0;
+
+ *encrypt_ret = true;
+
+ get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE);
+ return fscrypt_setup_encryption_info(inode,
+ &dir->i_crypt_info->ci_policy,
+ nonce);
+}
+EXPORT_SYMBOL_GPL(fscrypt_prepare_new_inode);
+
/**
* fscrypt_put_encryption_info() - free most of an inode's fscrypt data
* @inode: an inode being evicted
@@ -236,18 +236,19 @@ bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
}
/**
- * fscrypt_new_context_from_policy() - create a new fscrypt_context from
- * an fscrypt_policy
+ * fscrypt_new_context() - create a new fscrypt_context
* @ctx_u: output context
* @policy_u: input policy
+ * @nonce: nonce to use
*
* Create an fscrypt_context for an inode that is being assigned the given
- * encryption policy. A new nonce is randomly generated.
+ * encryption policy. @nonce must be a new random nonce.
*
* Return: the size of the new context in bytes.
*/
-static int fscrypt_new_context_from_policy(union fscrypt_context *ctx_u,
- const union fscrypt_policy *policy_u)
+static int fscrypt_new_context(union fscrypt_context *ctx_u,
+ const union fscrypt_policy *policy_u,
+ const u8 nonce[FSCRYPT_FILE_NONCE_SIZE])
{
memset(ctx_u, 0, sizeof(*ctx_u));
@@ -265,7 +266,7 @@ static int fscrypt_new_context_from_policy(union fscrypt_context *ctx_u,
memcpy(ctx->master_key_descriptor,
policy->master_key_descriptor,
sizeof(ctx->master_key_descriptor));
- get_random_bytes(ctx->nonce, sizeof(ctx->nonce));
+ memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);
return sizeof(*ctx);
}
case FSCRYPT_POLICY_V2: {
@@ -281,7 +282,7 @@ static int fscrypt_new_context_from_policy(union fscrypt_context *ctx_u,
memcpy(ctx->master_key_identifier,
policy->master_key_identifier,
sizeof(ctx->master_key_identifier));
- get_random_bytes(ctx->nonce, sizeof(ctx->nonce));
+ memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);
return sizeof(*ctx);
}
}
@@ -377,6 +378,7 @@ static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy)
static int set_encryption_policy(struct inode *inode,
const union fscrypt_policy *policy)
{
+ u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
union fscrypt_context ctx;
int ctxsize;
int err;
@@ -414,7 +416,8 @@ static int set_encryption_policy(struct inode *inode,
return -EINVAL;
}
- ctxsize = fscrypt_new_context_from_policy(&ctx, policy);
+ get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE);
+ ctxsize = fscrypt_new_context(&ctx, policy, nonce);
return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, NULL);
}
@@ -637,6 +640,7 @@ EXPORT_SYMBOL(fscrypt_has_permitted_context);
int fscrypt_inherit_context(struct inode *parent, struct inode *child,
void *fs_data, bool preload)
{
+ u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
union fscrypt_context ctx;
int ctxsize;
struct fscrypt_info *ci;
@@ -650,7 +654,8 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child,
if (ci == NULL)
return -ENOKEY;
- ctxsize = fscrypt_new_context_from_policy(&ctx, &ci->ci_policy);
+ get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE);
+ ctxsize = fscrypt_new_context(&ctx, &ci->ci_policy, nonce);
BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE);
res = parent->i_sb->s_cop->set_context(child, &ctx, ctxsize, fs_data);
@@ -660,6 +665,45 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child,
}
EXPORT_SYMBOL(fscrypt_inherit_context);
+/**
+ * fscrypt_set_context() - Set the fscrypt context of a new inode
+ * @inode: a new inode
+ * @fs_data: private data given by FS and passed to ->set_context()
+ *
+ * This should be called after fscrypt_prepare_new_inode(), generally during a
+ * filesystem transaction. Everything here must be %GFP_NOFS-safe.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fscrypt_set_context(struct inode *inode, void *fs_data)
+{
+ struct fscrypt_info *ci = inode->i_crypt_info;
+ union fscrypt_context ctx;
+ int ctxsize;
+
+ /* fscrypt_prepare_new_inode() should have set up the key already. */
+ if (WARN_ON_ONCE(!ci))
+ return -ENOKEY;
+
+ BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE);
+ ctxsize = fscrypt_new_context(&ctx, &ci->ci_policy, ci->ci_nonce);
+
+ /*
+ * This may be the first time the inode number is available, so do any
+ * delayed key setup that requires the inode number.
+ */
+ if (ci->ci_policy.version == FSCRYPT_POLICY_V2 &&
+ (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
+ const struct fscrypt_master_key *mk =
+ ci->ci_master_key->payload.data[0];
+
+ fscrypt_hash_inode_number(ci, mk);
+ }
+
+ return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, fs_data);
+}
+EXPORT_SYMBOL_GPL(fscrypt_set_context);
+
/**
* fscrypt_set_test_dummy_encryption() - handle '-o test_dummy_encryption'
* @sb: the filesystem on which test_dummy_encryption is being specified
@@ -158,6 +158,7 @@ int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg);
int fscrypt_has_permitted_context(struct inode *parent, struct inode *child);
int fscrypt_inherit_context(struct inode *parent, struct inode *child,
void *fs_data, bool preload);
+int fscrypt_set_context(struct inode *inode, void *fs_data);
struct fscrypt_dummy_context {
const union fscrypt_context *ctx;
@@ -184,6 +185,8 @@ int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
/* keysetup.c */
int fscrypt_get_encryption_info(struct inode *inode);
+int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
+ bool *encrypt_ret);
void fscrypt_put_encryption_info(struct inode *inode);
void fscrypt_free_inode(struct inode *inode);
int fscrypt_drop_inode(struct inode *inode);
@@ -347,6 +350,11 @@ static inline int fscrypt_inherit_context(struct inode *parent,
return -EOPNOTSUPP;
}
+static inline int fscrypt_set_context(struct inode *inode, void *fs_data)
+{
+ return -EOPNOTSUPP;
+}
+
struct fscrypt_dummy_context {
};
@@ -394,6 +402,15 @@ static inline int fscrypt_get_encryption_info(struct inode *inode)
return -EOPNOTSUPP;
}
+static inline int fscrypt_prepare_new_inode(struct inode *dir,
+ struct inode *inode,
+ bool *encrypt_ret)
+{
+ if (IS_ENCRYPTED(dir))
+ return -EOPNOTSUPP;
+ return 0;
+}
+
static inline void fscrypt_put_encryption_info(struct inode *inode)
{
return;