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This patch looks good to me. acked.
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>From e336ed0c05fbf4585efd09842e2e0896e945c9e8 Mon Sep 17 00:00:00 2001
From: Harry Ciao <qingtao.cao@xxxxxxxxxxxxx>
Date: Thu, 1 Sep 2011 11:29:44 +0800
Subject: [PATCH 48/67] libsepol: Permanently discard disabled branches of
tunables in expansion.
For a cond_node_t in one decl->cond_list queue, append its
avtrue_list or avfalse_list to the avrules list of its home decl
depending on its state value, so that these effective rules would
be permanently added to te_avtab hashtab.
On the other hand, the rules on the disabled unused list won't be
expanded and written to the raw policy at all.
Signed-off-by: Harry Ciao <qingtao.cao@xxxxxxxxxxxxx>
Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
---
libsepol/src/expand.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 98 insertions(+), 0 deletions(-)
diff --git a/libsepol/src/expand.c b/libsepol/src/expand.c
index 06f11f4..be41243 100644
--- a/libsepol/src/expand.c
+++ b/libsepol/src/expand.c
@@ -2665,6 +2665,94 @@ int expand_module_avrules(sepol_handle_t * handle, policydb_t * base,
return copy_and_expand_avrule_block(&state);
}
+static void discard_tunables(policydb_t *pol)
+{
+ avrule_block_t *block;
+ avrule_decl_t *decl;
+ cond_node_t *cur_node;
+ cond_expr_t *cur_expr;
+ int cur_state;
+ avrule_t *tail, *to_be_appended;
+
+ /* Iterate through all cond_node of all enabled decls, if a cond_node
+ * is about tunable, caculate its state value and concatenate one of
+ * its avrule list to the current decl->avrules list.
+ *
+ * Note, such tunable cond_node would be skipped over in expansion,
+ * so we won't have to worry about removing it from decl->cond_list
+ * here :-)
+ *
+ * If tunables and booleans co-exist in the expression of a cond_node,
+ * then tunables would be "transformed" as booleans.
+ */
+ for (block = pol->global; block != NULL; block = block->next) {
+ decl = block->enabled;
+ if (decl == NULL || decl->enabled == 0)
+ continue;
+
+ tail = decl->avrules;
+ while (tail && tail->next)
+ tail = tail->next;
+
+ for (cur_node = decl->cond_list; cur_node != NULL;
+ cur_node = cur_node->next) {
+ int booleans, tunables;
+ cond_bool_datum_t *booldatum;
+
+ booleans = tunables = 0;
+
+ for (cur_expr = cur_node->expr; cur_expr != NULL;
+ cur_expr = cur_expr->next) {
+ if (cur_expr->expr_type != COND_BOOL)
+ continue;
+ booldatum = pol->bool_val_to_struct[cur_expr->bool - 1];
+ if (booldatum->flags & COND_BOOL_FLAGS_TUNABLE)
+ tunables++;
+ else
+ booleans++;
+ }
+
+ /* bool_copy_callback() at link phase has ensured
+ * that no mixture of tunables and booleans in one
+ * expression. */
+ assert(!(booleans && tunables));
+
+ if (booleans) {
+ cur_node->flags &= ~COND_NODE_FLAGS_TUNABLE;
+ } else {
+ cur_node->flags |= COND_NODE_FLAGS_TUNABLE;
+ cur_state = cond_evaluate_expr(pol, cur_node->expr);
+ if (cur_state == -1) {
+ printf("Expression result was "
+ "undefined, skipping all"
+ "rules\n");
+ continue;
+ }
+
+ to_be_appended = (cur_state == 1) ?
+ cur_node->avtrue_list : cur_node->avfalse_list;
+
+ if (tail)
+ tail->next = to_be_appended;
+ else
+ tail = decl->avrules = to_be_appended;
+
+ /* Now that the effective branch has been
+ * appended, neutralize its original pointer */
+ if (cur_state == 1)
+ cur_node->avtrue_list = NULL;
+ else
+ cur_node->avfalse_list = NULL;
+
+ /* Update the tail of decl->avrules for
+ * further concatenation */
+ while (tail && tail->next)
+ tail = tail->next;
+ }
+ }
+ }
+}
+
/* Linking should always be done before calling expand, even if
* there is only a base since all optionals are dealt with at link time
* the base passed in should be indexed and avrule blocks should be
@@ -2678,6 +2766,16 @@ int expand_module(sepol_handle_t * handle,
expand_state_t state;
avrule_block_t *curblock;
+ /* Append tunable's avtrue_list or avfalse_list to the avrules list
+ * of its home decl depending on its state value, so that the effect
+ * rules of a tunable would be added to te_avtab permanently. Whereas
+ * the disabled unused branch would be discarded.
+ *
+ * Originally this function is called at the very end of link phase,
+ * however, we need to keep the linked policy intact for analysis
+ * purpose. */
+ discard_tunables(base);
+
expand_state_init(&state);
state.verbose = verbose;
--
1.7.6.2
