ext4 crypto: separate kernel and userspace structure for the key

Use struct ext4_encryption_key only for the master key passed via the
kernel keyring.

For internal kernel space users, we now use struct ext4_crypt_info.
This will allow us to put information from the policy structure so we
can cache it and avoid needing to constantly looking up the extended
attribute.  We will do this in a spearate patch.  This patch is mostly
mechnical to make it easier for patch review.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 10 insertions, 23 deletions

diff --git a/fs/ext4/crypto_fname.c b/fs/ext4/crypto_fname.c
index 23d7f1d..d9f08dd 100644
--- a/fs/ext4/crypto_fname.c
+++ b/fs/ext4/crypto_fname.c
@@ -278,33 +278,24 @@ void ext4_put_fname_crypto_ctx(struct ext4_fname_crypto_ctx **ctx)
 }
 
 /**
- * ext4_search_fname_crypto_ctx() -
- */
-static struct ext4_fname_crypto_ctx *ext4_search_fname_crypto_ctx(
-		const struct ext4_encryption_key *key)
-{
-	return NULL;
-}
-
-/**
  * ext4_alloc_fname_crypto_ctx() -
  */
 struct ext4_fname_crypto_ctx *ext4_alloc_fname_crypto_ctx(
-	const struct ext4_encryption_key *key)
+	const struct ext4_crypt_info *ci)
 {
 	struct ext4_fname_crypto_ctx *ctx;
 
 	ctx = kmalloc(sizeof(struct ext4_fname_crypto_ctx), GFP_NOFS);
 	if (ctx == NULL)
 		return ERR_PTR(-ENOMEM);
-	if (key->mode == EXT4_ENCRYPTION_MODE_INVALID) {
+	if (ci->ci_mode == EXT4_ENCRYPTION_MODE_INVALID) {
 		/* This will automatically set key mode to invalid
 		 * As enum for ENCRYPTION_MODE_INVALID is zero */
-		memset(&ctx->key, 0, sizeof(ctx->key));
+		memset(&ctx->ci, 0, sizeof(ctx->ci));
 	} else {
-		memcpy(&ctx->key, key, sizeof(struct ext4_encryption_key));
+		memcpy(&ctx->ci, ci, sizeof(struct ext4_crypt_info));
 	}
-	ctx->has_valid_key = (EXT4_ENCRYPTION_MODE_INVALID == key->mode)
+	ctx->has_valid_key = (EXT4_ENCRYPTION_MODE_INVALID == ci->ci_mode)
 		? 0 : 1;
 	ctx->ctfm_key_is_ready = 0;
 	ctx->ctfm = NULL;
@@ -335,21 +326,17 @@ struct ext4_fname_crypto_ctx *ext4_get_fname_crypto_ctx(
 	if (!ext4_has_encryption_key(inode))
 		ext4_generate_encryption_key(inode);
 
-	/* Get a crypto context based on the key.
-	 * A new context is allocated if no context matches the requested key.
-	 */
-	ctx = ext4_search_fname_crypto_ctx(&(ei->i_encryption_key));
-	if (ctx == NULL)
-		ctx = ext4_alloc_fname_crypto_ctx(&(ei->i_encryption_key));
+	/* Get a crypto context based on the key. */
+	ctx = ext4_alloc_fname_crypto_ctx(&(ei->i_crypt_info));
 	if (IS_ERR(ctx))
 		return ctx;
 
 	ctx->flags = ei->i_crypt_policy_flags;
 	if (ctx->has_valid_key) {
-		if (ctx->key.mode != EXT4_ENCRYPTION_MODE_AES_256_CTS) {
+		if (ctx->ci.ci_mode != EXT4_ENCRYPTION_MODE_AES_256_CTS) {
 			printk_once(KERN_WARNING
 				    "ext4: unsupported key mode %d\n",
-				    ctx->key.mode);
+				    ctx->ci.ci_mode);
 			return ERR_PTR(-ENOKEY);
 		}
 
@@ -389,7 +376,7 @@ struct ext4_fname_crypto_ctx *ext4_get_fname_crypto_ctx(
 			 * are pretty weak,
 			 * we directly use the inode master key */
 			res = crypto_ablkcipher_setkey(ctx->ctfm,
-					ctx->key.raw, ctx->key.size);
+					ctx->ci.ci_raw, ctx->ci.ci_size);
 			if (res) {
 				ext4_put_fname_crypto_ctx(&ctx);
 				return ERR_PTR(-EIO);