From: Mike Halcrow <mhalcrow@us.ibm.com>

Move logic to deal with AES special cases into the function that performs
string to cipher code mapping.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
DESC
ecryptfs-more-elegant-aes-key-size-manipulation-tidy
EDESC
From: Andrew Morton <akpm@osdl.org>

- braces are useful

- Dont' open-code ARRAY_SIZE()

Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 fs/ecryptfs/crypto.c          |   36 ++++++++++++++++++++++----------
 fs/ecryptfs/ecryptfs_kernel.h |    2 -
 fs/ecryptfs/keystore.c        |   21 ------------------
 3 files changed, 27 insertions(+), 32 deletions(-)

diff -puN fs/ecryptfs/crypto.c~ecryptfs-more-elegant-aes-key-size-manipulation fs/ecryptfs/crypto.c
--- a/fs/ecryptfs/crypto.c~ecryptfs-more-elegant-aes-key-size-manipulation
+++ a/fs/ecryptfs/crypto.c
@@ -1057,16 +1057,32 @@ ecryptfs_cipher_code_str_map[] = {
  *
  * Returns zero on no match, or the cipher code on match
  */
-u16 ecryptfs_code_for_cipher_string(char *str)
+u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
 {
 	int i;
-
-	for (i = 0; i < (sizeof(ecryptfs_cipher_code_str_map)
-			 / sizeof(struct ecryptfs_cipher_code_str_map_elem));
-	     i++)
-		if (strcmp(str, ecryptfs_cipher_code_str_map[i].cipher_str)==0)
-			return ecryptfs_cipher_code_str_map[i].cipher_code;
-	return 0;
+	u16 code = 0;
+	struct ecryptfs_cipher_code_str_map_elem *map =
+		ecryptfs_cipher_code_str_map;
+
+	if (strcmp(crypt_stat->cipher, "aes") == 0) {
+		switch (crypt_stat->key_size) {
+		case 16:
+			code = RFC2440_CIPHER_AES_128;
+			break;
+		case 24:
+			code = RFC2440_CIPHER_AES_192;
+			break;
+		case 32:
+			code = RFC2440_CIPHER_AES_256;
+		}
+	} else {
+		for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
+			if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){
+				code = map[i].cipher_code;
+				break;
+			}
+	}
+	return code;
 }
 
 /**
@@ -1082,9 +1098,7 @@ int ecryptfs_cipher_code_to_string(char 
 	int i;
 
 	str[0] = '\0';
-	for (i = 0; i < (sizeof(ecryptfs_cipher_code_str_map)
-			 / sizeof(struct ecryptfs_cipher_code_str_map_elem));
-	     i++)
+	for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
 		if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
 			strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
 	if (str[0] == '\0') {
diff -puN fs/ecryptfs/ecryptfs_kernel.h~ecryptfs-more-elegant-aes-key-size-manipulation fs/ecryptfs/ecryptfs_kernel.h
--- a/fs/ecryptfs/ecryptfs_kernel.h~ecryptfs-more-elegant-aes-key-size-manipulation
+++ a/fs/ecryptfs/ecryptfs_kernel.h
@@ -439,7 +439,7 @@ int ecryptfs_new_file_context(struct den
 int contains_ecryptfs_marker(char *data);
 int ecryptfs_read_header_region(char *data, struct dentry *dentry,
 				struct nameidata *nd);
-u16 ecryptfs_code_for_cipher_string(char *str);
+u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat);
 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code);
 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
 int ecryptfs_generate_key_packet_set(char *dest_base,
diff -puN fs/ecryptfs/keystore.c~ecryptfs-more-elegant-aes-key-size-manipulation fs/ecryptfs/keystore.c
--- a/fs/ecryptfs/keystore.c~ecryptfs-more-elegant-aes-key-size-manipulation
+++ a/fs/ecryptfs/keystore.c
@@ -923,32 +923,13 @@ encrypted_session_key_set:
 	}
 	(*packet_size) += packet_size_length;
 	dest[(*packet_size)++] = 0x04; /* version 4 */
-	cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher);
+	cipher_code = ecryptfs_code_for_cipher_string(crypt_stat);
 	if (cipher_code == 0) {
 		ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
 				"cipher [%s]\n", crypt_stat->cipher);
 		rc = -EINVAL;
 		goto out;
 	}
-	/* If it is AES, we need to get more specific. */
-	if (cipher_code == RFC2440_CIPHER_AES_128){
-		switch (crypt_stat->key_size) {
-		case 16:
-			break;
-		case 24:
-			cipher_code = RFC2440_CIPHER_AES_192;
-			break;
-		case 32:
-			cipher_code = RFC2440_CIPHER_AES_256;
-			break;
-		default:
-			rc = -EINVAL;
-			ecryptfs_printk(KERN_WARNING, "Unsupported AES key "
-					"size: [%d]\n",
-					crypt_stat->key_size);
-			goto out;
-		}
-	}
 	dest[(*packet_size)++] = cipher_code;
 	dest[(*packet_size)++] = 0x03;	/* S2K */
 	dest[(*packet_size)++] = 0x01;	/* MD5 (TODO: parameterize) */
_