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-rw-r--r--fs/crypto/keyinfo.c102
1 files changed, 68 insertions, 34 deletions
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 41f6025d5d7a..e997ca51192f 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -148,44 +148,64 @@ static int find_and_derive_key(const struct inode *inode,
return err;
}
-static const struct {
+static struct fscrypt_mode {
+ const char *friendly_name;
const char *cipher_str;
int keysize;
+ bool logged_impl_name;
} available_modes[] = {
- [FS_ENCRYPTION_MODE_AES_256_XTS] = { "xts(aes)", 64 },
- [FS_ENCRYPTION_MODE_AES_256_CTS] = { "cts(cbc(aes))", 32 },
- [FS_ENCRYPTION_MODE_AES_128_CBC] = { "cbc(aes)", 16 },
- [FS_ENCRYPTION_MODE_AES_128_CTS] = { "cts(cbc(aes))", 16 },
- [FS_ENCRYPTION_MODE_SPECK128_256_XTS] = { "xts(speck128)", 64 },
- [FS_ENCRYPTION_MODE_SPECK128_256_CTS] = { "cts(cbc(speck128))", 32 },
+ [FS_ENCRYPTION_MODE_AES_256_XTS] = {
+ .friendly_name = "AES-256-XTS",
+ .cipher_str = "xts(aes)",
+ .keysize = 64,
+ },
+ [FS_ENCRYPTION_MODE_AES_256_CTS] = {
+ .friendly_name = "AES-256-CTS-CBC",
+ .cipher_str = "cts(cbc(aes))",
+ .keysize = 32,
+ },
+ [FS_ENCRYPTION_MODE_AES_128_CBC] = {
+ .friendly_name = "AES-128-CBC",
+ .cipher_str = "cbc(aes)",
+ .keysize = 16,
+ },
+ [FS_ENCRYPTION_MODE_AES_128_CTS] = {
+ .friendly_name = "AES-128-CTS-CBC",
+ .cipher_str = "cts(cbc(aes))",
+ .keysize = 16,
+ },
+ [FS_ENCRYPTION_MODE_SPECK128_256_XTS] = {
+ .friendly_name = "Speck128/256-XTS",
+ .cipher_str = "xts(speck128)",
+ .keysize = 64,
+ },
+ [FS_ENCRYPTION_MODE_SPECK128_256_CTS] = {
+ .friendly_name = "Speck128/256-CTS-CBC",
+ .cipher_str = "cts(cbc(speck128))",
+ .keysize = 32,
+ },
};
-static int determine_cipher_type(struct fscrypt_info *ci, struct inode *inode,
- const char **cipher_str_ret, int *keysize_ret)
+static struct fscrypt_mode *
+select_encryption_mode(const struct fscrypt_info *ci, const struct inode *inode)
{
- u32 mode;
-
if (!fscrypt_valid_enc_modes(ci->ci_data_mode, ci->ci_filename_mode)) {
fscrypt_warn(inode->i_sb,
"inode %lu uses unsupported encryption modes (contents mode %d, filenames mode %d)",
inode->i_ino, ci->ci_data_mode,
ci->ci_filename_mode);
- return -EINVAL;
+ return ERR_PTR(-EINVAL);
}
- if (S_ISREG(inode->i_mode)) {
- mode = ci->ci_data_mode;
- } else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) {
- mode = ci->ci_filename_mode;
- } else {
- WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
- inode->i_ino, (inode->i_mode & S_IFMT));
- return -EINVAL;
- }
+ if (S_ISREG(inode->i_mode))
+ return &available_modes[ci->ci_data_mode];
+
+ if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+ return &available_modes[ci->ci_filename_mode];
- *cipher_str_ret = available_modes[mode].cipher_str;
- *keysize_ret = available_modes[mode].keysize;
- return 0;
+ WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
+ inode->i_ino, (inode->i_mode & S_IFMT));
+ return ERR_PTR(-EINVAL);
}
static void put_crypt_info(struct fscrypt_info *ci)
@@ -270,8 +290,7 @@ int fscrypt_get_encryption_info(struct inode *inode)
struct fscrypt_info *crypt_info;
struct fscrypt_context ctx;
struct crypto_skcipher *ctfm;
- const char *cipher_str;
- int keysize;
+ struct fscrypt_mode *mode;
u8 *raw_key = NULL;
int res;
@@ -315,40 +334,55 @@ int fscrypt_get_encryption_info(struct inode *inode)
memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
sizeof(crypt_info->ci_master_key));
- res = determine_cipher_type(crypt_info, inode, &cipher_str, &keysize);
- if (res)
+ mode = select_encryption_mode(crypt_info, inode);
+ if (IS_ERR(mode)) {
+ res = PTR_ERR(mode);
goto out;
+ }
/*
* This cannot be a stack buffer because it is passed to the scatterlist
* crypto API as part of key derivation.
*/
res = -ENOMEM;
- raw_key = kmalloc(keysize, GFP_NOFS);
+ raw_key = kmalloc(mode->keysize, GFP_NOFS);
if (!raw_key)
goto out;
- res = find_and_derive_key(inode, &ctx, raw_key, keysize);
+ res = find_and_derive_key(inode, &ctx, raw_key, mode->keysize);
if (res)
goto out;
- ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
+ ctfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0);
if (IS_ERR(ctfm)) {
res = PTR_ERR(ctfm);
fscrypt_warn(inode->i_sb,
"error allocating '%s' transform for inode %lu: %d",
- cipher_str, inode->i_ino, res);
+ mode->cipher_str, inode->i_ino, res);
goto out;
}
+ if (unlikely(!mode->logged_impl_name)) {
+ /*
+ * fscrypt performance can vary greatly depending on which
+ * crypto algorithm implementation is used. Help people debug
+ * performance problems by logging the ->cra_driver_name the
+ * first time a mode is used. Note that multiple threads can
+ * race here, but it doesn't really matter.
+ */
+ mode->logged_impl_name = true;
+ pr_info("fscrypt: %s using implementation \"%s\"\n",
+ mode->friendly_name,
+ crypto_skcipher_alg(ctfm)->base.cra_driver_name);
+ }
crypt_info->ci_ctfm = ctfm;
crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY);
- res = crypto_skcipher_setkey(ctfm, raw_key, keysize);
+ res = crypto_skcipher_setkey(ctfm, raw_key, mode->keysize);
if (res)
goto out;
if (S_ISREG(inode->i_mode) &&
crypt_info->ci_data_mode == FS_ENCRYPTION_MODE_AES_128_CBC) {
- res = init_essiv_generator(crypt_info, raw_key, keysize);
+ res = init_essiv_generator(crypt_info, raw_key, mode->keysize);
if (res) {
fscrypt_warn(inode->i_sb,
"error initializing ESSIV generator for inode %lu: %d",