selinux: Fix an uninitialized variable BUG/panic in selinux_secattr_to_sid()

At some point during the 2.6.27 development cycle two new fields were added
to the SELinux context structure, a string pointer and a length field.  The
code in selinux_secattr_to_sid() was not modified and as a result these two
fields were left uninitialized which could result in erratic behavior,
including kernel panics, when NetLabel is used.  This patch fixes the
problem by fully initializing the context in selinux_secattr_to_sid() before
use and reducing the level of direct context manipulation done to help
prevent future problems.

Please apply this to the 2.6.27-rcX release stream.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 876b815c1ba4e785094f449320a62a7709abc482..ab0cc0c7b9444e60a8cf625c0edb1aaa479456ba 100644 (file)
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2907,6 +2907,7 @@ int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
                if (ctx == NULL)
                        goto netlbl_secattr_to_sid_return;
 
+               context_init(&ctx_new);
                ctx_new.user = ctx->user;
                ctx_new.role = ctx->role;
                ctx_new.type = ctx->type;
@@ -2915,13 +2916,9 @@ int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
                        if (ebitmap_netlbl_import(&ctx_new.range.level[0].cat,
                                                  secattr->attr.mls.cat) != 0)
                                goto netlbl_secattr_to_sid_return;
-                       ctx_new.range.level[1].cat.highbit =
-                               ctx_new.range.level[0].cat.highbit;
-                       ctx_new.range.level[1].cat.node =
-                               ctx_new.range.level[0].cat.node;
-               } else {
-                       ebitmap_init(&ctx_new.range.level[0].cat);
-                       ebitmap_init(&ctx_new.range.level[1].cat);
+                       memcpy(&ctx_new.range.level[1].cat,
+                              &ctx_new.range.level[0].cat,
+                              sizeof(ctx_new.range.level[0].cat));
                }
                if (mls_context_isvalid(&policydb, &ctx_new) != 1)
                        goto netlbl_secattr_to_sid_return_cleanup;