[PATCH 4.9 055/101] libceph: implement CEPHX_V2 calculation mode

From: Greg Kroah-Hartman
Date: Thu Dec 06 2018 - 09:52:26 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ilya Dryomov <idryomov@xxxxxxxxx>

commit cc255c76c70f7a87d97939621eae04b600d9f4a1 upstream.

Derive the signature from the entire buffer (both AES cipher blocks)
instead of using just the first half of the first block, leaving out
data_crc entirely.

This addresses CVE-2018-1129.

Link: http://tracker.ceph.com/issues/24837
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Reviewed-by: Sage Weil <sage@xxxxxxxxxx>
[bwh: Backported to 4.9:
- Define and test the feature bit in the old way
- Don't change any other feature bits in ceph_features.h]
Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/ceph/ceph_features.h | 4 +
net/ceph/auth_x.c | 77 +++++++++++++++++++++++++++----------
2 files changed, 61 insertions(+), 20 deletions(-)

--- a/include/linux/ceph/ceph_features.h
+++ b/include/linux/ceph/ceph_features.h
@@ -76,6 +76,7 @@
// duplicated since it was introduced at the same time as CEPH_FEATURE_CRUSH_TUNABLES5
#define CEPH_FEATURE_NEW_OSDOPREPLY_ENCODING (1ULL<<58) /* New, v7 encoding */
#define CEPH_FEATURE_FS_FILE_LAYOUT_V2 (1ULL<<58) /* file_layout_t */
+#define CEPH_FEATURE_CEPHX_V2 (1ULL<<61) // *do not share this bit*

/*
* The introduction of CEPH_FEATURE_OSD_SNAPMAPPER caused the feature
@@ -124,7 +125,8 @@ static inline u64 ceph_sanitize_features
CEPH_FEATURE_MSGR_KEEPALIVE2 | \
CEPH_FEATURE_CRUSH_V4 | \
CEPH_FEATURE_CRUSH_TUNABLES5 | \
- CEPH_FEATURE_NEW_OSDOPREPLY_ENCODING)
+ CEPH_FEATURE_NEW_OSDOPREPLY_ENCODING | \
+ CEPH_FEATURE_CEPHX_V2)

#define CEPH_FEATURES_REQUIRED_DEFAULT \
(CEPH_FEATURE_NOSRCADDR | \
--- a/net/ceph/auth_x.c
+++ b/net/ceph/auth_x.c
@@ -8,6 +8,7 @@

#include <linux/ceph/decode.h>
#include <linux/ceph/auth.h>
+#include <linux/ceph/ceph_features.h>
#include <linux/ceph/libceph.h>
#include <linux/ceph/messenger.h>

@@ -799,26 +800,64 @@ static int calc_signature(struct ceph_x_
__le64 *psig)
{
void *enc_buf = au->enc_buf;
- struct {
- __le32 len;
- __le32 header_crc;
- __le32 front_crc;
- __le32 middle_crc;
- __le32 data_crc;
- } __packed *sigblock = enc_buf + ceph_x_encrypt_offset();
- int ret;
-
- sigblock->len = cpu_to_le32(4*sizeof(u32));
- sigblock->header_crc = msg->hdr.crc;
- sigblock->front_crc = msg->footer.front_crc;
- sigblock->middle_crc = msg->footer.middle_crc;
- sigblock->data_crc = msg->footer.data_crc;
- ret = ceph_x_encrypt(&au->session_key, enc_buf, CEPHX_AU_ENC_BUF_LEN,
- sizeof(*sigblock));
- if (ret < 0)
- return ret;
+ int ret;
+
+ if (msg->con->peer_features & CEPH_FEATURE_CEPHX_V2) {
+ struct {
+ __le32 len;
+ __le32 header_crc;
+ __le32 front_crc;
+ __le32 middle_crc;
+ __le32 data_crc;
+ } __packed *sigblock = enc_buf + ceph_x_encrypt_offset();
+
+ sigblock->len = cpu_to_le32(4*sizeof(u32));
+ sigblock->header_crc = msg->hdr.crc;
+ sigblock->front_crc = msg->footer.front_crc;
+ sigblock->middle_crc = msg->footer.middle_crc;
+ sigblock->data_crc = msg->footer.data_crc;
+
+ ret = ceph_x_encrypt(&au->session_key, enc_buf,
+ CEPHX_AU_ENC_BUF_LEN, sizeof(*sigblock));
+ if (ret < 0)
+ return ret;
+
+ *psig = *(__le64 *)(enc_buf + sizeof(u32));
+ } else {
+ struct {
+ __le32 header_crc;
+ __le32 front_crc;
+ __le32 front_len;
+ __le32 middle_crc;
+ __le32 middle_len;
+ __le32 data_crc;
+ __le32 data_len;
+ __le32 seq_lower_word;
+ } __packed *sigblock = enc_buf;
+ struct {
+ __le64 a, b, c, d;
+ } __packed *penc = enc_buf;
+ int ciphertext_len;
+
+ sigblock->header_crc = msg->hdr.crc;
+ sigblock->front_crc = msg->footer.front_crc;
+ sigblock->front_len = msg->hdr.front_len;
+ sigblock->middle_crc = msg->footer.middle_crc;
+ sigblock->middle_len = msg->hdr.middle_len;
+ sigblock->data_crc = msg->footer.data_crc;
+ sigblock->data_len = msg->hdr.data_len;
+ sigblock->seq_lower_word = *(__le32 *)&msg->hdr.seq;
+
+ /* no leading len, no ceph_x_encrypt_header */
+ ret = ceph_crypt(&au->session_key, true, enc_buf,
+ CEPHX_AU_ENC_BUF_LEN, sizeof(*sigblock),
+ &ciphertext_len);
+ if (ret)
+ return ret;
+
+ *psig = penc->a ^ penc->b ^ penc->c ^ penc->d;
+ }

- *psig = *(__le64 *)(enc_buf + sizeof(u32));
return 0;
}