On 08/17/2017 02:04 PM, Daniel Cashman wrote:
From: Dan Cashman <[email protected]>

Signed-off-by: Dan Cashman <[email protected]>
Change-Id: I5a72f2e6c339baee8ebc07e3e9176296320e2c80
---
  libsepol/cil/include/cil/cil.h   |  1 +
  libsepol/cil/src/cil.c           |  5 +++++
  libsepol/cil/src/cil_build_ast.c | 46 ++++++++++++++++++++++++++++++++++------
  libsepol/cil/src/cil_internal.h  |  1 +
  secilc/secilc.c                  |  9 +++++++-
  5 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/libsepol/cil/include/cil/cil.h b/libsepol/cil/include/cil/cil.h
index 4507892c..4df646a0 100644
--- a/libsepol/cil/include/cil/cil.h
+++ b/libsepol/cil/include/cil/cil.h
@@ -46,6 +46,7 @@ extern int cil_userprefixes_to_string(cil_db_t *db, char 
**out, size_t *size);
  extern int cil_selinuxusers_to_string(cil_db_t *db, char **out, size_t *size);
  extern int cil_filecons_to_string(cil_db_t *db, char **out, size_t *size);
  extern void cil_set_disable_dontaudit(cil_db_t *db, int disable_dontaudit);
+extern void cil_set_multiple_decls(cil_db_t *db, int multiple_decls);
  extern void cil_set_disable_neverallow(cil_db_t *db, int disable_neverallow);
  extern void cil_set_preserve_tunables(cil_db_t *db, int preserve_tunables);
  extern int cil_set_handle_unknown(cil_db_t *db, int handle_unknown);
diff --git a/libsepol/cil/src/cil.c b/libsepol/cil/src/cil.c
index 9b9ccc36..e8bbbfdf 100644
--- a/libsepol/cil/src/cil.c
+++ b/libsepol/cil/src/cil.c
@@ -1675,6 +1675,11 @@ void cil_set_mls(struct cil_db *db, int mls)
        db->mls = mls;
  }
+void cil_set_multiple_decls(struct cil_db *db, int multiple_decls)
+{
+       db->multiple_decls = multiple_decls;
+}
+
  void cil_set_target_platform(struct cil_db *db, int target_platform)
  {
        db->target_platform = target_platform;
diff --git a/libsepol/cil/src/cil_build_ast.c b/libsepol/cil/src/cil_build_ast.c
index 36cc6735..9a2fd0d5 100644
--- a/libsepol/cil/src/cil_build_ast.c
+++ b/libsepol/cil/src/cil_build_ast.c
@@ -82,10 +82,33 @@ exit:
        return rc;
  }
+/*
+ * Determine whether or not multiple declarations of the same key can share a
+ * datum, given the new datum and the one already present in a given symtab.
+ */
+int cil_is_datum_multiple_decl(__attribute__((unused)) struct cil_symtab_datum 
*cur,
+                               __attribute__((unused)) struct cil_symtab_datum 
*old,
+                               enum cil_flavor f)
+{
+       int rc = CIL_FALSE;
+
+       switch (f) {
+       case CIL_TYPE:
+       case CIL_TYPEATTRIBUTE:
+               /* type and typeattribute statements insert empty datums, ret 
true */
+               rc = CIL_TRUE;
+               break;
+       default:
+               break;
+       }
+       return rc;
+}
+
  int cil_gen_node(__attribute__((unused)) struct cil_db *db, struct 
cil_tree_node *ast_node, struct cil_symtab_datum *datum, hashtab_key_t key, 
enum cil_sym_index sflavor, enum cil_flavor nflavor)
  {
        int rc = SEPOL_ERR;
        symtab_t *symtab = NULL;
+       struct cil_symtab_datum *prev;
rc = __cil_verify_name((const char*)key);
        if (rc != SEPOL_OK) {
@@ -103,15 +126,24 @@ int cil_gen_node(__attribute__((unused)) struct cil_db 
*db, struct cil_tree_node
        if (symtab != NULL) {
                rc = cil_symtab_insert(symtab, (hashtab_key_t)key, datum, 
ast_node);
                if (rc == SEPOL_EEXIST) {
-                       cil_log(CIL_ERR, "Re-declaration of %s %s\n",
-                               cil_node_to_string(ast_node), key);
-                       if (cil_symtab_get_datum(symtab, key, &datum) == 
SEPOL_OK) {
-                               if (sflavor == CIL_SYM_BLOCKS) {
-                                       struct cil_tree_node *node = 
datum->nodes->head->data;
-                                       cil_tree_log(node, CIL_ERR, "Previous 
declaration");
+                       if (!db->multiple_decls ||
+                           cil_symtab_get_datum(symtab, (hashtab_key_t)key, 
&prev) != SEPOL_OK ||
+                           !cil_is_datum_multiple_decl(datum, prev, nflavor)) {
+
+                               /* multiple_decls not ok, ret error */
+                               cil_log(CIL_ERR, "Re-declaration of %s %s\n",
+                                       cil_node_to_string(ast_node), key);
+                               if (cil_symtab_get_datum(symtab, key, &datum) 
== SEPOL_OK) {
+                                       if (sflavor == CIL_SYM_BLOCKS) {
+                                               struct cil_tree_node *node = 
datum->nodes->head->data;
+                                               cil_tree_log(node, CIL_ERR, 
"Previous declaration");
+                                       }
                                }
+                               goto exit;
                        }
-                       goto exit;
+                       /* multiple_decls is enabled and works for this datum 
type, add node */
+                       cil_list_append(prev->nodes, CIL_NODE, ast_node);
+                       ast_node->data = prev;

You also need:
cil_symtab_datum_destroy(datum);
free(datum);

                }
        }
diff --git a/libsepol/cil/src/cil_internal.h b/libsepol/cil/src/cil_internal.h
index aee3f00c..abfacd8d 100644
--- a/libsepol/cil/src/cil_internal.h
+++ b/libsepol/cil/src/cil_internal.h
@@ -312,6 +312,7 @@ struct cil_db {
        int preserve_tunables;
        int handle_unknown;
        int mls;
+       int multiple_decls;
        int target_platform;
        int policy_version;
  };

You also need to add cil_set_multiple_decls to libsepol/src/libsepol.map.in


diff --git a/secilc/secilc.c b/secilc/secilc.c
index f2232e72..0be6975b 100644
--- a/secilc/secilc.c
+++ b/secilc/secilc.c
@@ -63,6 +63,7 @@ static __attribute__((__noreturn__)) void usage(const char 
*prog)
        printf("                                 statement if present in the 
policy\n");
        printf("  -D, --disable-dontaudit        do not add dontaudit rules to the 
binary policy\n");
        printf("  -P, --preserve-tunables        treat tunables as booleans\n");
+       printf("  -m, --multiple-decls           allow some statements to be 
re-declared\n");
        printf("  -N, --disable-neverallow       do not check neverallow 
rules\n");
        printf("  -G, --expand-generated         Expand and remove auto-generated 
attributes\n");
        printf("  -X, --expand-size <SIZE>       Expand type attributes with fewer than 
<SIZE>\n");
@@ -89,6 +90,7 @@ int main(int argc, char *argv[])
        int target = SEPOL_TARGET_SELINUX;
        int mls = -1;
        int disable_dontaudit = 0;
+       int multiple_decls = 0;
        int disable_neverallow = 0;
        int preserve_tunables = 0;
        int handle_unknown = -1;
@@ -108,6 +110,7 @@ int main(int argc, char *argv[])
                {"policyversion", required_argument, 0, 'c'},
                {"handle-unknown", required_argument, 0, 'U'},
                {"disable-dontaudit", no_argument, 0, 'D'},
+               {"multiple-decls", no_argument, 0, 'm'},
                {"disable-neverallow", no_argument, 0, 'N'},
                {"preserve-tunables", no_argument, 0, 'P'},
                {"output", required_argument, 0, 'o'},
@@ -119,7 +122,7 @@ int main(int argc, char *argv[])
        int i;
while (1) {
-               opt_char = getopt_long(argc, argv, "o:f:U:hvt:M:PDNc:GX:", 
long_opts, &opt_index);
+               opt_char = getopt_long(argc, argv, "o:f:U:hvt:M:PDmNc:GX:", 
long_opts, &opt_index);
                if (opt_char == -1) {
                        break;
                }
@@ -175,6 +178,9 @@ int main(int argc, char *argv[])
                        case 'D':
                                disable_dontaudit = 1;
                                break;
+                       case 'm':
+                               multiple_decls = 1;
+                               break;
                        case 'N':
                                disable_neverallow = 1;
                                break;
@@ -223,6 +229,7 @@ int main(int argc, char *argv[])
cil_db_init(&db);
        cil_set_disable_dontaudit(db, disable_dontaudit);
+       cil_set_multiple_decls(db, multiple_decls);
        cil_set_disable_neverallow(db, disable_neverallow);
        cil_set_preserve_tunables(db, preserve_tunables);
        if (handle_unknown != -1) {


Overall, the patch seems to work. I am a little worried that I might be missing a particular corner case where it won't.

Jim


--
James Carter <[email protected]>
National Security Agency

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