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authorTheodore Ts'o <tytso@mit.edu>2017-01-02 23:12:17 +0300
committerTheodore Ts'o <tytso@mit.edu>2017-01-02 23:39:46 +0300
commit5bbdcbbb396196f1c94110ad7a041e90de95c4c2 (patch)
treeecc38d3c7cfd63dec89605e2db99825ce6f91e94 /fs/crypto
parent58ae74683ae2c07cd717a91799edb50231061938 (diff)
downloadlinux-5bbdcbbb396196f1c94110ad7a041e90de95c4c2.tar.xz
fscrypt: make test_dummy_encryption require a keyring key
Currently, the test_dummy_encryption ext4 mount option, which exists only to test encrypted I/O paths with xfstests, overrides all per-inode encryption keys with a fixed key. This change minimizes test_dummy_encryption-specific code path changes by supplying a fake context for directories which are not encrypted for use when creating new directories, files, or symlinks. This allows us to properly exercise the keyring lookup, derivation, and context inheritance code paths. Before mounting a file system using test_dummy_encryption, userspace must execute the following shell commands: mode='\x00\x00\x00\x00' raw="$(printf ""\\\\x%02x"" $(seq 0 63))" if lscpu | grep "Byte Order" | grep -q Little ; then size='\x40\x00\x00\x00' else size='\x00\x00\x00\x40' fi key="${mode}${raw}${size}" keyctl new_session echo -n -e "${key}" | keyctl padd logon fscrypt:4242424242424242 @s Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/crypto')
-rw-r--r--fs/crypto/keyinfo.c15
-rw-r--r--fs/crypto/policy.c22
2 files changed, 13 insertions, 24 deletions
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 95cd4c3b06c3..80f145c8d550 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -206,12 +206,16 @@ retry:
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res < 0) {
- if (!fscrypt_dummy_context_enabled(inode))
+ if (!fscrypt_dummy_context_enabled(inode) ||
+ inode->i_sb->s_cop->is_encrypted(inode))
return res;
+ /* Fake up a context for an unencrypted directory */
+ memset(&ctx, 0, sizeof(ctx));
ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
- ctx.flags = 0;
+ memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
+ res = sizeof(ctx);
} else if (res != sizeof(ctx)) {
return -EINVAL;
}
@@ -247,12 +251,6 @@ retry:
if (!raw_key)
goto out;
- if (fscrypt_dummy_context_enabled(inode)) {
- memset(raw_key, 0x42, keysize/2);
- memset(raw_key+keysize/2, 0x24, keysize - (keysize/2));
- goto got_key;
- }
-
res = validate_user_key(crypt_info, &ctx, raw_key,
FS_KEY_DESC_PREFIX, FS_KEY_DESC_PREFIX_SIZE);
if (res && inode->i_sb->s_cop->key_prefix) {
@@ -270,7 +268,6 @@ retry:
} else if (res) {
goto out;
}
-got_key:
ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
if (!ctfm || IS_ERR(ctfm)) {
res = ctfm ? PTR_ERR(ctfm) : -ENOMEM;
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 4c99972899c7..14b76da71269 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -198,9 +198,9 @@ EXPORT_SYMBOL(fscrypt_has_permitted_context);
* @parent: Parent inode from which the context is inherited.
* @child: Child inode that inherits the context from @parent.
* @fs_data: private data given by FS.
- * @preload: preload child i_crypt_info
+ * @preload: preload child i_crypt_info if true
*
- * Return: Zero on success, non-zero otherwise
+ * Return: 0 on success, -errno on failure
*/
int fscrypt_inherit_context(struct inode *parent, struct inode *child,
void *fs_data, bool preload)
@@ -221,19 +221,11 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child,
return -ENOKEY;
ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
- if (fscrypt_dummy_context_enabled(parent)) {
- ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
- ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
- ctx.flags = 0;
- memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
- res = 0;
- } else {
- ctx.contents_encryption_mode = ci->ci_data_mode;
- ctx.filenames_encryption_mode = ci->ci_filename_mode;
- ctx.flags = ci->ci_flags;
- memcpy(ctx.master_key_descriptor, ci->ci_master_key,
- FS_KEY_DESCRIPTOR_SIZE);
- }
+ ctx.contents_encryption_mode = ci->ci_data_mode;
+ ctx.filenames_encryption_mode = ci->ci_filename_mode;
+ ctx.flags = ci->ci_flags;
+ memcpy(ctx.master_key_descriptor, ci->ci_master_key,
+ FS_KEY_DESCRIPTOR_SIZE);
get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
res = parent->i_sb->s_cop->set_context(child, &ctx,
sizeof(ctx), fs_data);