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From: Maxim Levitsky <mlevitsk@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Kevin Wolf" <kwolf@redhat.com>, "Fam Zheng" <fam@euphon.net>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	qemu-block@nongnu.org, "Markus Armbruster" <armbru@redhat.com>,
	"Max Reitz" <mreitz@redhat.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Maxim Levitsky" <mlevitsk@redhat.com>
Subject: [Qemu-devel] [PATCH 05/13] qcrypto-luks: clear the masterkey and password before freeing them always
Date: Wed, 14 Aug 2019 23:22:11 +0300
Message-ID: <20190814202219.1870-6-mlevitsk@redhat.com> (raw)
In-Reply-To: <20190814202219.1870-1-mlevitsk@redhat.com>

While there are other places where these are still stored in memory,
this is still one less key material area that can be sniffed with
various side channel attacks



Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 crypto/block-luks.c | 52 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 44 insertions(+), 8 deletions(-)

diff --git a/crypto/block-luks.c b/crypto/block-luks.c
index e1a4df94b7..336e633df4 100644
--- a/crypto/block-luks.c
+++ b/crypto/block-luks.c
@@ -1023,8 +1023,18 @@ qcrypto_block_luks_load_key(QCryptoBlock *block,
  cleanup:
     qcrypto_ivgen_free(ivgen);
     qcrypto_cipher_free(cipher);
-    g_free(splitkey);
-    g_free(possiblekey);
+
+    if (splitkey) {
+        memset(splitkey, 0, splitkeylen);
+        g_free(splitkey);
+    }
+
+    if (possiblekey) {
+        memset(possiblekey, 0, masterkeylen(luks));
+        g_free(possiblekey);
+
+    }
+
     return ret;
 }
 
@@ -1161,16 +1171,34 @@ qcrypto_block_luks_open(QCryptoBlock *block,
     block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
     block->payload_offset = luks->header.payload_offset * block->sector_size;
 
-    g_free(masterkey);
-    g_free(password);
+    if (masterkey) {
+        memset(masterkey, 0, masterkeylen(luks));
+        g_free(masterkey);
+    }
+
+    if (password) {
+        memset(password, 0, strlen(password));
+        g_free(password);
+    }
+
     return 0;
 
  fail:
-    g_free(masterkey);
+
+    if (masterkey) {
+        memset(masterkey, 0, masterkeylen(luks));
+        g_free(masterkey);
+    }
+
+    if (password) {
+        memset(password, 0, strlen(password));
+        g_free(password);
+    }
+
     qcrypto_block_free_cipher(block);
     qcrypto_ivgen_free(block->ivgen);
+
     g_free(luks);
-    g_free(password);
     return ret;
 }
 
@@ -1459,7 +1487,10 @@ qcrypto_block_luks_create(QCryptoBlock *block,
 
     memset(masterkey, 0, luks->header.key_bytes);
     g_free(masterkey);
+
+    memset(password, 0, strlen(password));
     g_free(password);
+
     g_free(cipher_mode_spec);
 
     return 0;
@@ -1467,9 +1498,14 @@ qcrypto_block_luks_create(QCryptoBlock *block,
  error:
     if (masterkey) {
         memset(masterkey, 0, luks->header.key_bytes);
+        g_free(masterkey);
     }
-    g_free(masterkey);
-    g_free(password);
+
+    if (password) {
+        memset(password, 0, strlen(password));
+        g_free(password);
+    }
+
     g_free(cipher_mode_spec);
 
     qcrypto_block_free_cipher(block);
-- 
2.17.2



  parent reply index

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-14 20:22 [Qemu-devel] [PATCH 00/13] RFC: luks/encrypted qcow2 key management Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 01/13] block-crypto: misc refactoring Maxim Levitsky
2019-08-20 16:38   ` Max Reitz
2019-08-22  0:05     ` Maxim Levitsky
2019-08-22 14:34       ` Max Reitz
2019-08-22 15:04         ` Maxim Levitsky
2019-08-21 15:39   ` Daniel P. Berrangé
2019-08-22  0:08     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 02/13] qcrypto-luks: " Maxim Levitsky
2019-08-15 21:40   ` [Qemu-devel] [Qemu-block] " John Snow
2019-08-19 14:21     ` Maxim Levitsky
2019-08-22 10:29     ` Daniel P. Berrangé
2019-08-22 11:04       ` Maxim Levitsky
2019-08-22 11:10         ` Daniel P. Berrangé
2019-08-22 11:13           ` Maxim Levitsky
2019-08-20 17:36   ` [Qemu-devel] " Max Reitz
2019-08-21 23:59     ` Maxim Levitsky
2019-08-22 14:32       ` Max Reitz
2019-08-25 10:46         ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 03/13] qcrypto-luks: refactoring: extract load/store/check/parse header functions Maxim Levitsky
2019-08-20 18:01   ` Max Reitz
2019-08-21 22:43     ` Maxim Levitsky
2019-08-22 10:32       ` Daniel P. Berrangé
2019-08-22 10:57         ` Maxim Levitsky
2019-08-22 10:34       ` Daniel P. Berrangé
2019-08-25 14:11         ` Maxim Levitsky
2019-08-22 10:38   ` Daniel P. Berrangé
2019-08-25 14:09     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 04/13] qcrypto-luks: refactoring: simplify the math used for keyslot locations Maxim Levitsky
2019-08-22 10:47   ` Daniel P. Berrangé
2019-08-25 14:30     ` Maxim Levitsky
2019-08-14 20:22 ` Maxim Levitsky [this message]
2019-08-20 18:12   ` [Qemu-devel] [PATCH 05/13] qcrypto-luks: clear the masterkey and password before freeing them always Max Reitz
2019-08-21 22:40     ` Maxim Levitsky
2019-08-22 10:49     ` Daniel P. Berrangé
2019-08-22 10:56       ` Maxim Levitsky
2019-08-25 15:31         ` Maxim Levitsky
2019-08-25 17:15           ` Maxim Levitsky
2019-08-27  8:55           ` Daniel P. Berrangé
2019-08-21 23:01   ` [Qemu-devel] [Qemu-block] " Nir Soffer
2019-08-21 23:11     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 06/13] qcrypto-luks: implement more rigorous header checking Maxim Levitsky
2019-08-22 11:04   ` Daniel P. Berrangé
2019-08-25 15:40     ` Maxim Levitsky
2019-08-25 16:08       ` Maxim Levitsky
2019-08-26 13:31         ` Eric Blake
2019-08-26 13:39           ` Maxim Levitsky
2019-08-27  8:56         ` Daniel P. Berrangé
2019-08-14 20:22 ` [Qemu-devel] [PATCH 07/13] block: add manage-encryption command (qmp and blockdev) Maxim Levitsky
2019-08-20 18:27   ` Max Reitz
2019-08-21 22:32     ` Maxim Levitsky
2019-08-22 11:14     ` Daniel P. Berrangé
2019-08-21 11:47   ` Markus Armbruster
2019-08-21 22:24     ` Maxim Levitsky
2019-08-22 14:07       ` Markus Armbruster
2019-08-25 16:42         ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 08/13] qcrypto: add the plumbing for encryption management Maxim Levitsky
2019-08-22 11:16   ` Daniel P. Berrangé
2019-08-22 11:47     ` Maxim Levitsky
2019-08-22 11:49       ` Daniel P. Berrangé
2019-08-14 20:22 ` [Qemu-devel] [PATCH 09/13] qcrypto-luks: implement the encryption key management Maxim Levitsky
2019-08-22 11:27   ` Daniel P. Berrangé
2019-08-25 17:01     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 10/13] block/crypto: " Maxim Levitsky
2019-08-22 11:29   ` Daniel P. Berrangé
2019-08-22 11:36     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 11/13] block/qcow2: implement the encryption key managment Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 12/13] qemu-img: implement key management Maxim Levitsky
2019-08-20 18:29   ` Max Reitz
2019-08-21 22:33     ` Maxim Levitsky
2019-08-22 11:32     ` Daniel P. Berrangé
2019-08-22 14:42       ` Max Reitz
2019-08-25 17:04         ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 13/13] iotests : add tests for encryption " Maxim Levitsky
2019-08-14 21:08 ` [Qemu-devel] [PATCH 00/13] RFC: luks/encrypted qcow2 " Eric Blake
2019-08-15  8:49   ` Maxim Levitsky
2019-08-15  9:10   ` Kevin Wolf
2019-08-15 14:18     ` Markus Armbruster
2019-08-15 14:44       ` Maxim Levitsky
2019-08-15 15:00         ` Eric Blake
2019-08-19 12:35           ` Maxim Levitsky
2019-08-21 11:31             ` Markus Armbruster
2019-08-21 13:22               ` Maxim Levitsky
2019-08-20 17:59 ` Max Reitz
2019-08-21 22:00   ` Maxim Levitsky
2019-08-22 11:35 ` Daniel P. Berrangé
2019-08-25 17:10   ` Maxim Levitsky

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