[v3,2/2] libsepol/cil: Return error when identifier declared as both type and attribute
diff mbox series

Message ID 20200526185058.42827-2-jwcart2@gmail.com
State Accepted
Headers show
Series
  • [v3,1/2] libsepol/cil: Initialize the multiple_decls field of the cil db
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Commit Message

James Carter May 26, 2020, 6:50 p.m. UTC
CIL allows a type to be redeclared when using the multiple declarations
option ("-m" or "--muliple-decls"), but make it an error for an identifier
to be declared as both a type and an attribute.

Change the error message so that it always gives the location and flavor
of both declarations. The flavors will be the same in all other cases,
but in this case they explain why there is an error even if multiple
declartions are allowed.

Fixes: Commit fafe4c212bf6c32c ("libsepol: cil: Add ability to redeclare types[attributes]")
Reported-by: Topi Miettinen <toiwoton@gmail.com>
Signed-off-by: James Carter <jwcart2@gmail.com>
---
v2: Added these changes
v3: Removed the error message about not creating a node

 libsepol/cil/src/cil_build_ast.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

Comments

Topi Miettinen May 27, 2020, 7:02 a.m. UTC | #1
On 26.5.2020 21.50, James Carter wrote:
> CIL allows a type to be redeclared when using the multiple declarations
> option ("-m" or "--muliple-decls"), but make it an error for an identifier
> to be declared as both a type and an attribute.
> 
> Change the error message so that it always gives the location and flavor
> of both declarations. The flavors will be the same in all other cases,
> but in this case they explain why there is an error even if multiple
> declartions are allowed.
> 
> Fixes: Commit fafe4c212bf6c32c ("libsepol: cil: Add ability to redeclare types[attributes]")
> Reported-by: Topi Miettinen <toiwoton@gmail.com>
> Signed-off-by: James Carter <jwcart2@gmail.com>

Thanks, this prevents mismatching declarations. Does this also fix the 
memory issue and prevent that buggy policy could get loaded sometimes?

-Topi
James Carter May 27, 2020, 12:06 p.m. UTC | #2
On Wed, May 27, 2020 at 3:02 AM Topi Miettinen <toiwoton@gmail.com> wrote:
>
> On 26.5.2020 21.50, James Carter wrote:
> > CIL allows a type to be redeclared when using the multiple declarations
> > option ("-m" or "--muliple-decls"), but make it an error for an identifier
> > to be declared as both a type and an attribute.
> >
> > Change the error message so that it always gives the location and flavor
> > of both declarations. The flavors will be the same in all other cases,
> > but in this case they explain why there is an error even if multiple
> > declartions are allowed.
> >
> > Fixes: Commit fafe4c212bf6c32c ("libsepol: cil: Add ability to redeclare types[attributes]")
> > Reported-by: Topi Miettinen <toiwoton@gmail.com>
> > Signed-off-by: James Carter <jwcart2@gmail.com>
>
> Thanks, this prevents mismatching declarations. Does this also fix the
> memory issue and prevent that buggy policy could get loaded sometimes?
>

Yes, the two patches together will prevent the buggy policy from being
loaded. It will always give an error now.

Jim

> -Topi
Stephen Smalley May 27, 2020, 1:16 p.m. UTC | #3
On Tue, May 26, 2020 at 2:51 PM James Carter <jwcart2@gmail.com> wrote:
>
> CIL allows a type to be redeclared when using the multiple declarations
> option ("-m" or "--muliple-decls"), but make it an error for an identifier
> to be declared as both a type and an attribute.
>
> Change the error message so that it always gives the location and flavor
> of both declarations. The flavors will be the same in all other cases,
> but in this case they explain why there is an error even if multiple
> declartions are allowed.
>
> Fixes: Commit fafe4c212bf6c32c ("libsepol: cil: Add ability to redeclare types[attributes]")
> Reported-by: Topi Miettinen <toiwoton@gmail.com>
> Signed-off-by: James Carter <jwcart2@gmail.com>

Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Stephen Smalley May 29, 2020, 12:52 p.m. UTC | #4
On Wed, May 27, 2020 at 9:16 AM Stephen Smalley
<stephen.smalley.work@gmail.com> wrote:
>
> On Tue, May 26, 2020 at 2:51 PM James Carter <jwcart2@gmail.com> wrote:
> >
> > CIL allows a type to be redeclared when using the multiple declarations
> > option ("-m" or "--muliple-decls"), but make it an error for an identifier
> > to be declared as both a type and an attribute.
> >
> > Change the error message so that it always gives the location and flavor
> > of both declarations. The flavors will be the same in all other cases,
> > but in this case they explain why there is an error even if multiple
> > declartions are allowed.
> >
> > Fixes: Commit fafe4c212bf6c32c ("libsepol: cil: Add ability to redeclare types[attributes]")
> > Reported-by: Topi Miettinen <toiwoton@gmail.com>
> > Signed-off-by: James Carter <jwcart2@gmail.com>
>
> Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>

Applied.

Patch
diff mbox series

diff --git a/libsepol/cil/src/cil_build_ast.c b/libsepol/cil/src/cil_build_ast.c
index fcecdc4f..60ecaaff 100644
--- a/libsepol/cil/src/cil_build_ast.c
+++ b/libsepol/cil/src/cil_build_ast.c
@@ -87,7 +87,7 @@  exit:
  * 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,
+                               struct cil_symtab_datum *old,
                                enum cil_flavor f)
 {
 	int rc = CIL_FALSE;
@@ -95,8 +95,12 @@  int cil_is_datum_multiple_decl(__attribute__((unused)) struct cil_symtab_datum *
 	switch (f) {
 	case CIL_TYPE:
 	case CIL_TYPEATTRIBUTE:
-		/* type and typeattribute statements insert empty datums, ret true */
-		rc = CIL_TRUE;
+		if (!old || f != FLAVOR(old)) {
+			rc = CIL_FALSE;
+		} else {
+			/* type and typeattribute statements insert empty datums */
+			rc = CIL_TRUE;
+		}
 		break;
 	default:
 		break;
@@ -126,19 +130,20 @@  int cil_gen_node(struct cil_db *db, struct cil_tree_node *ast_node, struct cil_s
 	if (symtab != NULL) {
 		rc = cil_symtab_insert(symtab, (hashtab_key_t)key, datum, ast_node);
 		if (rc == SEPOL_EEXIST) {
+			rc = cil_symtab_get_datum(symtab, (hashtab_key_t)key, &prev);
+			if (rc != SEPOL_OK) {
+				cil_log(CIL_ERR, "Re-declaration of %s %s, but previous declaration could not be found\n",cil_node_to_string(ast_node), key);
+				goto exit;
+			}
 			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 */
+				struct cil_tree_node *node = NODE(prev);
 				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");
-					}
-				}
+				cil_tree_log(node, CIL_ERR, "Previous declaration of %s",
+					cil_node_to_string(node));
+				rc = SEPOL_ERR;
 				goto exit;
 			}
 			/* multiple_decls is enabled and works for this datum type, add node */
@@ -169,7 +174,6 @@  int cil_gen_node(struct cil_db *db, struct cil_tree_node *ast_node, struct cil_s
 	return SEPOL_OK;
 
 exit:
-	cil_log(CIL_ERR, "Failed to create node\n");
 	return rc;
 }