UBUNTU: SAUCE: LSM: Use lsmblob in security_kernel_act_as

Change the security_kernel_act_as interface to use a lsmblob
structure in place of the single u32 secid in support of
module stacking. Change its only caller, set_security_override,
to do the same. Change that one's only caller,
set_security_override_from_ctx, to call it with the new
parameter type.

The security module hook is unchanged, still taking a secid.
The infrastructure passes the correct entry from the lsmblob.
lsmblob_init() is used to fill the lsmblob structure, however
this will be removed later in the series when security_secctx_to_secid()
is undated to provide a lsmblob instead of a secid.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/include/linux/cred.h b/include/linux/cred.h
index fcbc6885cc0936ed9bbb25cf4bdcf4101b366f82..eb02e85142397f12d0e0ef21cfe6fc7ed9db9aba 100644 (file)
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -18,6 +18,7 @@
 
 struct cred;
 struct inode;
+struct lsmblob;
 
 /*
  * COW Supplementary groups list
@@ -165,7 +166,7 @@ extern const struct cred *override_creds(const struct cred *);
 extern void revert_creds(const struct cred *);
 extern struct cred *prepare_kernel_cred(struct task_struct *);
 extern int change_create_files_as(struct cred *, struct inode *);
-extern int set_security_override(struct cred *, u32);
+extern int set_security_override(struct cred *, struct lsmblob *);
 extern int set_security_override_from_ctx(struct cred *, const char *);
 extern int set_create_files_as(struct cred *, struct inode *);
 extern int cred_fscmp(const struct cred *, const struct cred *);

diff --git a/include/linux/security.h b/include/linux/security.h
index 00267626df9cc46da23553de9feb3814b3fc5c1f..e03708dc189be8e83166ba061c2a7b52dc3d280e 100644 (file)
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -458,7 +458,7 @@ void security_cred_free(struct cred *cred);
 int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
 void security_transfer_creds(struct cred *new, const struct cred *old);
 void security_cred_getsecid(const struct cred *c, u32 *secid);
-int security_kernel_act_as(struct cred *new, u32 secid);
+int security_kernel_act_as(struct cred *new, struct lsmblob *blob);
 int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_module_request(char *kmod_name);
 int security_kernel_load_data(enum kernel_load_data_id id, bool contents);
@@ -1100,7 +1100,8 @@ static inline void security_transfer_creds(struct cred *new,
 {
 }
 
-static inline int security_kernel_act_as(struct cred *cred, u32 secid)
+static inline int security_kernel_act_as(struct cred *cred,
+                                        struct lsmblob *blob)
 {
        return 0;
 }

diff --git a/kernel/cred.c b/kernel/cred.c
index 1ae0b4948a5a820d4ea3f758c733418dcb3f286f..486e8160c019a6f479a8a7d11ab572cf3bcd0d73 100644 (file)
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -773,14 +773,14 @@ EXPORT_SYMBOL(prepare_kernel_cred);
 /**
  * set_security_override - Set the security ID in a set of credentials
  * @new: The credentials to alter
- * @secid: The LSM security ID to set
+ * @blob: The LSM security information to set
  *
  * Set the LSM security ID in a set of credentials so that the subjective
  * security is overridden when an alternative set of credentials is used.
  */
-int set_security_override(struct cred *new, u32 secid)
+int set_security_override(struct cred *new, struct lsmblob *blob)
 {
-       return security_kernel_act_as(new, secid);
+       return security_kernel_act_as(new, blob);
 }
 EXPORT_SYMBOL(set_security_override);
 
@@ -796,6 +796,7 @@ EXPORT_SYMBOL(set_security_override);
  */
 int set_security_override_from_ctx(struct cred *new, const char *secctx)
 {
+       struct lsmblob blob;
        u32 secid;
        int ret;
 
@@ -803,7 +804,8 @@ int set_security_override_from_ctx(struct cred *new, const char *secctx)
        if (ret < 0)
                return ret;
 
-       return set_security_override(new, secid);
+       lsmblob_init(&blob, secid);
+       return set_security_override(new, &blob);
 }
 EXPORT_SYMBOL(set_security_override_from_ctx);
 

diff --git a/security/security.c b/security/security.c
index 673dd6536ce7bdb1cebaf24cf9ea792e079d49f8..0c17c739a213a24cd91ce338fa67da9c8fcb49c9 100644 (file)
--- a/security/security.c
+++ b/security/security.c
@@ -1756,9 +1756,19 @@ void security_cred_getsecid(const struct cred *c, u32 *secid)
 }
 EXPORT_SYMBOL(security_cred_getsecid);
 
-int security_kernel_act_as(struct cred *new, u32 secid)
+int security_kernel_act_as(struct cred *new, struct lsmblob *blob)
 {
-       return call_int_hook(kernel_act_as, 0, new, secid);
+       struct security_hook_list *hp;
+       int rc;
+
+       hlist_for_each_entry(hp, &security_hook_heads.kernel_act_as, list) {
+               if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+                       continue;
+               rc = hp->hook.kernel_act_as(new, blob->secid[hp->lsmid->slot]);
+               if (rc != 0)
+                       return rc;
+       }
+       return 0;
 }
 
 int security_kernel_create_files_as(struct cred *new, struct inode *inode)