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-rw-r--r--fs/crypto/policy.c35
1 files changed, 29 insertions, 6 deletions
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 8a054e6d1e68..80b8ca0f340b 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -694,6 +694,32 @@ const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir)
}
/**
+ * fscrypt_context_for_new_inode() - create an encryption context for a new inode
+ * @ctx: where context should be written
+ * @inode: inode from which to fetch policy and nonce
+ *
+ * Given an in-core "prepared" (via fscrypt_prepare_new_inode) inode,
+ * generate a new context and write it to ctx. ctx _must_ be at least
+ * FSCRYPT_SET_CONTEXT_MAX_SIZE bytes.
+ *
+ * Return: size of the resulting context or a negative error code.
+ */
+int fscrypt_context_for_new_inode(void *ctx, struct inode *inode)
+{
+ struct fscrypt_info *ci = inode->i_crypt_info;
+
+ BUILD_BUG_ON(sizeof(union fscrypt_context) !=
+ FSCRYPT_SET_CONTEXT_MAX_SIZE);
+
+ /* fscrypt_prepare_new_inode() should have set up the key already. */
+ if (WARN_ON_ONCE(!ci))
+ return -ENOKEY;
+
+ return fscrypt_new_context(ctx, &ci->ci_policy, ci->ci_nonce);
+}
+EXPORT_SYMBOL_GPL(fscrypt_context_for_new_inode);
+
+/**
* 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()
@@ -709,12 +735,9 @@ int fscrypt_set_context(struct inode *inode, void *fs_data)
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);
+ ctxsize = fscrypt_context_for_new_inode(&ctx, inode);
+ if (ctxsize < 0)
+ return ctxsize;
/*
* This may be the first time the inode number is available, so do any