libceph: implement CEPHX_V2 calculation mode

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@gmail.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

2 files changed, 60 insertions, 20 deletions

diff --git a/include/linux/ceph/ceph_features.h b/include/linux/ceph/ceph_features.h
index 59042d5ac520..70f42eef813b 100644
--- a/include/linux/ceph/ceph_features.h
+++ b/include/linux/ceph/ceph_features.h
@@ -165,9 +165,9 @@ DEFINE_CEPH_FEATURE(58, 1, FS_FILE_LAYOUT_V2) // overlap
 DEFINE_CEPH_FEATURE(59, 1, FS_BTIME)
 DEFINE_CEPH_FEATURE(59, 1, FS_CHANGE_ATTR) // overlap
 DEFINE_CEPH_FEATURE(59, 1, MSG_ADDR2) // overlap
-DEFINE_CEPH_FEATURE(60, 1, BLKIN_TRACING)  // *do not share this bit*
+DEFINE_CEPH_FEATURE(60, 1, OSD_RECOVERY_DELETES) // *do not share this bit*
+DEFINE_CEPH_FEATURE(61, 1, CEPHX_V2)             // *do not share this bit*
 
-DEFINE_CEPH_FEATURE(61, 1, RESERVED2)          // unused, but slow down!
 DEFINE_CEPH_FEATURE(62, 1, RESERVED)           // do not use; used as a sentinal
 DEFINE_CEPH_FEATURE_DEPRECATED(63, 1, RESERVED_BROKEN, LUMINOUS) // client-facing
 
@@ -209,7 +209,8 @@ DEFINE_CEPH_FEATURE_DEPRECATED(63, 1, RESERVED_BROKEN, LUMINOUS) // client-facin
 	 CEPH_FEATURE_SERVER_JEWEL |		\
 	 CEPH_FEATURE_MON_STATEFUL_SUB |	\
 	 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 |	 \
diff --git a/net/ceph/auth_x.c b/net/ceph/auth_x.c
index ce28bb07d8fd..10eb759bbcb4 100644
--- a/net/ceph/auth_x.c
+++ b/net/ceph/auth_x.c
@@ -9,6 +9,7 @@
 
 #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>
 
@@ -803,26 +804,64 @@ static int calc_signature(struct ceph_x_authorizer *au, struct ceph_msg *msg,
 			  __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;
+	if (!CEPH_HAVE_FEATURE(msg->con->peer_features, 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;
 }