libceph: add nocephx_sign_messages option

Support for message signing was merged into 3.19, along with
nocephx_require_signatures option.  But, all that option does is allow
the kernel client to talk to clusters that don't support MSG_AUTH
feature bit.  That's pretty useless, given that it's been supported
since bobtail.

Meanwhile, if one disables message signing on the server side with
"cephx sign messages = false", it becomes impossible to use the kernel
client since it expects messages to be signed if MSG_AUTH was
negotiated.  Add nocephx_sign_messages option to support this use case.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

3 files changed, 20 insertions, 1 deletions

diff --git a/net/ceph/auth_x.c b/net/ceph/auth_x.c
index 3a544ca6b5ce..10d87753ed87 100644
--- 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/libceph.h>
 #include <linux/ceph/messenger.h>
 
 #include "crypto.h"
@@ -698,6 +699,9 @@ static int ceph_x_sign_message(struct ceph_auth_handshake *auth,
 {
         int ret;
 
+        if (ceph_test_opt(from_msgr(msg->con->msgr), NOMSGSIGN))
+                return 0;
+
         ret = calcu_signature((struct ceph_x_authorizer *)auth->authorizer,
                               msg, &msg->footer.sig);
         if (ret < 0)
@@ -712,6 +716,9 @@ static int ceph_x_check_message_signature(struct ceph_auth_handshake *auth,
         __le64 sig_check;
         int ret;
 
+        if (ceph_test_opt(from_msgr(msg->con->msgr), NOMSGSIGN))
+                return 0;
+
         ret = calcu_signature((struct ceph_x_authorizer *)auth->authorizer,
                               msg, &sig_check);
         if (ret < 0)
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index d1494d1a8592..6b4d3a1684de 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -245,6 +245,8 @@ enum {
         Opt_nocrc,
         Opt_cephx_require_signatures,
         Opt_nocephx_require_signatures,
+        Opt_cephx_sign_messages,
+        Opt_nocephx_sign_messages,
         Opt_tcp_nodelay,
         Opt_notcp_nodelay,
 };
@@ -267,6 +269,8 @@ static match_table_t opt_tokens = {
         {Opt_nocrc, "nocrc"},
         {Opt_cephx_require_signatures, "cephx_require_signatures"},
         {Opt_nocephx_require_signatures, "nocephx_require_signatures"},
+        {Opt_cephx_sign_messages, "cephx_sign_messages"},
+        {Opt_nocephx_sign_messages, "nocephx_sign_messages"},
         {Opt_tcp_nodelay, "tcp_nodelay"},
         {Opt_notcp_nodelay, "notcp_nodelay"},
         {-1, NULL}
@@ -491,6 +495,12 @@ ceph_parse_options(char *options, const char *dev_name,
                 case Opt_nocephx_require_signatures:
                         opt->flags |= CEPH_OPT_NOMSGAUTH;
                         break;
+                case Opt_cephx_sign_messages:
+                        opt->flags &= ~CEPH_OPT_NOMSGSIGN;
+                        break;
+                case Opt_nocephx_sign_messages:
+                        opt->flags |= CEPH_OPT_NOMSGSIGN;
+                        break;
 
                 case Opt_tcp_nodelay:
                         opt->flags |= CEPH_OPT_TCP_NODELAY;
@@ -534,6 +544,8 @@ int ceph_print_client_options(struct seq_file *m, struct ceph_client *client)
                 seq_puts(m, "nocrc,");
         if (opt->flags & CEPH_OPT_NOMSGAUTH)
                 seq_puts(m, "nocephx_require_signatures,");
+        if (opt->flags & CEPH_OPT_NOMSGSIGN)
+                seq_puts(m, "nocephx_sign_messages,");
         if ((opt->flags & CEPH_OPT_TCP_NODELAY) == 0)
                 seq_puts(m, "notcp_nodelay,");
 
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 11108076bac3..0cc5608b2c8f 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2677,7 +2677,7 @@ more:
                 if (ret <= 0) {
                         switch (ret) {
                         case -EBADMSG:
-                                con->error_msg = "bad crc";
+                                con->error_msg = "bad crc/signature";
                                 /* fall through */
                         case -EBADE:
                                 ret = -EIO;