keys: allow the callout data to be passed as a blob rather than a string

Allow the callout data to be passed as a blob rather than a string for
internal kernel services that call any request_key_*() interface other than
request_key().  request_key() itself still takes a NUL-terminated string.

The functions that change are:

	request_key_with_auxdata()
	request_key_async()
	request_key_async_with_auxdata()

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 19 deletions

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 5ecc5057fb54..a3f94c60692d 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -161,21 +161,22 @@ error_alloc:
  * call out to userspace for key construction
  * - we ignore program failure and go on key status instead
  */
-static int construct_key(struct key *key, const char *callout_info, void *aux)
+static int construct_key(struct key *key, const void *callout_info,
+                         size_t callout_len, void *aux)
 {
         struct key_construction *cons;
         request_key_actor_t actor;
         struct key *authkey;
         int ret;
 
-        kenter("%d,%s,%p", key->serial, callout_info, aux);
+        kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux);
 
         cons = kmalloc(sizeof(*cons), GFP_KERNEL);
         if (!cons)
                 return -ENOMEM;
 
         /* allocate an authorisation key */
-        authkey = request_key_auth_new(key, callout_info);
+        authkey = request_key_auth_new(key, callout_info, callout_len);
         if (IS_ERR(authkey)) {
                 kfree(cons);
                 ret = PTR_ERR(authkey);
@@ -331,6 +332,7 @@ alloc_failed:
 static struct key *construct_key_and_link(struct key_type *type,
                                           const char *description,
                                           const char *callout_info,
+                                          size_t callout_len,
                                           void *aux,
                                           struct key *dest_keyring,
                                           unsigned long flags)
@@ -348,7 +350,7 @@ static struct key *construct_key_and_link(struct key_type *type,
         key_user_put(user);
 
         if (ret == 0) {
-                ret = construct_key(key, callout_info, aux);
+                ret = construct_key(key, callout_info, callout_len, aux);
                 if (ret < 0)
                         goto construction_failed;
         }
@@ -370,7 +372,8 @@ construction_failed:
  */
 struct key *request_key_and_link(struct key_type *type,
                                  const char *description,
-                                 const char *callout_info,
+                                 const void *callout_info,
+                                 size_t callout_len,
                                  void *aux,
                                  struct key *dest_keyring,
                                  unsigned long flags)
@@ -378,8 +381,8 @@ struct key *request_key_and_link(struct key_type *type,
         struct key *key;
         key_ref_t key_ref;
 
-        kenter("%s,%s,%s,%p,%p,%lx",
-               type->name, description, callout_info, aux,
+        kenter("%s,%s,%p,%zu,%p,%p,%lx",
+               type->name, description, callout_info, callout_len, aux,
                dest_keyring, flags);
 
         /* search all the process keyrings for a key */
@@ -398,7 +401,8 @@ struct key *request_key_and_link(struct key_type *type,
                         goto error;
 
                 key = construct_key_and_link(type, description, callout_info,
-                                             aux, dest_keyring, flags);
+                                             callout_len, aux, dest_keyring,
+                                             flags);
         }
 
 error:
@@ -434,10 +438,13 @@ struct key *request_key(struct key_type *type,
                         const char *callout_info)
 {
         struct key *key;
+        size_t callout_len = 0;
         int ret;
 
-        key = request_key_and_link(type, description, callout_info, NULL,
-                                   NULL, KEY_ALLOC_IN_QUOTA);
+        if (callout_info)
+                callout_len = strlen(callout_info);
+        key = request_key_and_link(type, description, callout_info, callout_len,
+                                   NULL, NULL, KEY_ALLOC_IN_QUOTA);
         if (!IS_ERR(key)) {
                 ret = wait_for_key_construction(key, false);
                 if (ret < 0) {
@@ -458,14 +465,15 @@ EXPORT_SYMBOL(request_key);
  */
 struct key *request_key_with_auxdata(struct key_type *type,
                                      const char *description,
-                                     const char *callout_info,
+                                     const void *callout_info,
+                                     size_t callout_len,
                                      void *aux)
 {
         struct key *key;
         int ret;
 
-        key = request_key_and_link(type, description, callout_info, aux,
-                                   NULL, KEY_ALLOC_IN_QUOTA);
+        key = request_key_and_link(type, description, callout_info, callout_len,
+                                   aux, NULL, KEY_ALLOC_IN_QUOTA);
         if (!IS_ERR(key)) {
                 ret = wait_for_key_construction(key, false);
                 if (ret < 0) {
@@ -485,10 +493,12 @@ EXPORT_SYMBOL(request_key_with_auxdata);
  */
 struct key *request_key_async(struct key_type *type,
                               const char *description,
-                              const char *callout_info)
+                              const void *callout_info,
+                              size_t callout_len)
 {
-        return request_key_and_link(type, description, callout_info, NULL,
-                                    NULL, KEY_ALLOC_IN_QUOTA);
+        return request_key_and_link(type, description, callout_info,
+                                    callout_len, NULL, NULL,
+                                    KEY_ALLOC_IN_QUOTA);
 }
 EXPORT_SYMBOL(request_key_async);
 
@@ -500,10 +510,11 @@ EXPORT_SYMBOL(request_key_async);
  */
 struct key *request_key_async_with_auxdata(struct key_type *type,
                                            const char *description,
-                                           const char *callout_info,
+                                           const void *callout_info,
+                                           size_t callout_len,
                                            void *aux)
 {
-        return request_key_and_link(type, description, callout_info, aux,
-                                    NULL, KEY_ALLOC_IN_QUOTA);
+        return request_key_and_link(type, description, callout_info,
+                                    callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);
 }
 EXPORT_SYMBOL(request_key_async_with_auxdata);