libceph: Get secret from the kernel keys api when mounting with key=NAME.

Signed-off-by: Tommi Virtanen <tommi.virtanen@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>

2 files changed, 59 insertions, 0 deletions

diff --git a/net/ceph/Kconfig b/net/ceph/Kconfig
index ad424049b0cf..be683f2d401f 100644
--- a/net/ceph/Kconfig
+++ b/net/ceph/Kconfig
@@ -4,6 +4,7 @@ config CEPH_LIB
         select LIBCRC32C
         select CRYPTO_AES
         select CRYPTO
+        select KEYS
         default n
         help
           Choose Y or M here to include cephlib, which provides the
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 02e084f29d24..c92bc8d50597 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -5,6 +5,8 @@
 #include <linux/fs.h>
 #include <linux/inet.h>
 #include <linux/in6.h>
+#include <linux/key.h>
+#include <keys/user-type.h>
 #include <linux/module.h>
 #include <linux/mount.h>
 #include <linux/parser.h>
@@ -197,6 +199,7 @@ enum {
         Opt_fsid,
         Opt_name,
         Opt_secret,
+        Opt_key,
         Opt_ip,
         Opt_last_string,
         /* string args above */
@@ -213,6 +216,7 @@ static match_table_t opt_tokens = {
         {Opt_fsid, "fsid=%s"},
         {Opt_name, "name=%s"},
         {Opt_secret, "secret=%s"},
+        {Opt_key, "key=%s"},
         {Opt_ip, "ip=%s"},
         /* string args above */
         {Opt_noshare, "noshare"},
@@ -232,6 +236,50 @@ void ceph_destroy_options(struct ceph_options *opt)
 }
 EXPORT_SYMBOL(ceph_destroy_options);
 
+/* get secret from key store */
+static int get_secret(struct ceph_crypto_key *dst, const char *name) {
+        struct key *ukey;
+        int key_err;
+        int err = 0;
+        struct user_key_payload *payload;
+        void *p;
+
+        ukey = request_key(&key_type_user, name, NULL);
+        if (!ukey || IS_ERR(ukey)) {
+                /* request_key errors don't map nicely to mount(2)
+                   errors; don't even try, but still printk */
+                key_err = PTR_ERR(ukey);
+                switch (key_err) {
+                case -ENOKEY:
+                        pr_warning("ceph: Mount failed due to key not found: %s\n", name);
+                        break;
+                case -EKEYEXPIRED:
+                        pr_warning("ceph: Mount failed due to expired key: %s\n", name);
+                        break;
+                case -EKEYREVOKED:
+                        pr_warning("ceph: Mount failed due to revoked key: %s\n", name);
+                        break;
+                default:
+                        pr_warning("ceph: Mount failed due to unknown key error"
+                               " %d: %s\n", key_err, name);
+                }
+                err = -EPERM;
+                goto out;
+        }
+
+        payload = ukey->payload.data;
+        p = payload->data;
+        err = ceph_crypto_key_decode(dst, &p, p + payload->datalen);
+        if (err)
+                goto out_key;
+        /* pass through, err is 0 */
+
+out_key:
+        key_put(ukey);
+out:
+        return err;
+}
+
 int ceph_parse_options(struct ceph_options **popt, char *options,
                        const char *dev_name, const char *dev_name_end,
                        int (*parse_extra_token)(char *c, void *private),
@@ -328,6 +376,16 @@ int ceph_parse_options(struct ceph_options **popt, char *options,
                         if (err < 0)
                                 goto out;
                         break;
+                case Opt_key:
+                        opt->key = kzalloc(sizeof(*opt->key), GFP_KERNEL);
+                        if (!opt->key) {
+                                err = -ENOMEM;
+                                goto out;
+                        }
+                        err = get_secret(opt->key, argstr[0].from);
+                        if (err < 0)
+                                goto out;
+                        break;
 
                         /* misc */
                 case Opt_osdtimeout: