diff mbox series

[v2,3/5] selinux: convert cond_av_list to array

Message ID 20200117085836.445797-4-omosnace@redhat.com (mailing list archive)
State Superseded
Headers show
Series selinux: Assorted simplifications and cleanups | expand

Commit Message

Ondrej Mosnacek Jan. 17, 2020, 8:58 a.m. UTC 
Since it is fixed-size after allocation and we know the size beforehand,
using a plain old array is simpler and more efficient.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
---
 security/selinux/ss/conditional.c | 125 ++++++++++++------------------
 security/selinux/ss/conditional.h |   8 +-
 2 files changed, 53 insertions(+), 80 deletions(-)

Comments

Paul Moore Jan. 31, 2020, 4:17 a.m. UTC | #1 
On Fri, Jan 17, 2020 at 3:58 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
> Since it is fixed-size after allocation and we know the size beforehand,
> using a plain old array is simpler and more efficient.
>
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
> ---
>  security/selinux/ss/conditional.c | 125 ++++++++++++------------------
>  security/selinux/ss/conditional.h |   8 +-
>  2 files changed, 53 insertions(+), 80 deletions(-)

...

> diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
> index c8a02c9b23ee..b847fd2a6a51 100644
> --- a/security/selinux/ss/conditional.c
> +++ b/security/selinux/ss/conditional.c
> @@ -255,19 +249,17 @@ err:
>
>  struct cond_insertf_data {
>         struct policydb *p;
> +       struct avtab_node **dst;
>         struct cond_av_list *other;
> -       struct cond_av_list *head;
> -       struct cond_av_list *tail;
>  };
>
>  static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum *d, void *ptr)
>  {
>         struct cond_insertf_data *data = ptr;
>         struct policydb *p = data->p;
> -       struct cond_av_list *other = data->other, *list, *cur;
>         struct avtab_node *node_ptr;
> -       u8 found;
> -       int rc = -EINVAL;
> +       u32 i;
> +       bool found;
>
>         /*
>          * For type rules we have to make certain there aren't any
> @@ -277,7 +269,7 @@ static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum
>         if (k->specified & AVTAB_TYPE) {
>                 if (avtab_search(&p->te_avtab, k)) {
>                         pr_err("SELinux: type rule already exists outside of a conditional.\n");
> -                       goto err;
> +                       return -EINVAL;
>                 }
>                 /*
>                  * If we are reading the false list other will be a pointer to
> @@ -287,29 +279,29 @@ static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum
>                  * If we are reading the true list (other == NULL) there shouldn't
>                  * be any other entries.
>                  */
> -               if (other) {
> +               if (data->other) {
>                         node_ptr = avtab_search_node(&p->te_cond_avtab, k);
>                         if (node_ptr) {
>                                 if (avtab_search_node_next(node_ptr, k->specified)) {
>                                         pr_err("SELinux: too many conflicting type rules.\n");
> -                                       goto err;
> +                                       return -EINVAL;
>                                 }
> -                               found = 0;
> -                               for (cur = other; cur; cur = cur->next) {
> -                                       if (cur->node == node_ptr) {
> -                                               found = 1;
> +                               found = false;
> +                               for (i = 0; i < data->other->len; i++) {
> +                                       if (data->other->nodes[i] == node_ptr) {
> +                                               found = true;
>                                                 break;
>                                         }
>                                 }

Can you explain why you got rid of the "other" variable in this
function?  It seems like it would be nice in the loop above.
Ondrej Mosnacek Feb. 3, 2020, 9:13 a.m. UTC | #2 
On Fri, Jan 31, 2020 at 5:17 AM Paul Moore <paul@paul-moore.com> wrote:
>
> On Fri, Jan 17, 2020 at 3:58 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
> > Since it is fixed-size after allocation and we know the size beforehand,
> > using a plain old array is simpler and more efficient.
> >
> > Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> > Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
> > ---
> >  security/selinux/ss/conditional.c | 125 ++++++++++++------------------
> >  security/selinux/ss/conditional.h |   8 +-
> >  2 files changed, 53 insertions(+), 80 deletions(-)
>
> ...
>
> > diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
> > index c8a02c9b23ee..b847fd2a6a51 100644
> > --- a/security/selinux/ss/conditional.c
> > +++ b/security/selinux/ss/conditional.c
> > @@ -255,19 +249,17 @@ err:
> >
> >  struct cond_insertf_data {
> >         struct policydb *p;
> > +       struct avtab_node **dst;
> >         struct cond_av_list *other;
> > -       struct cond_av_list *head;
> > -       struct cond_av_list *tail;
> >  };
> >
> >  static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum *d, void *ptr)
> >  {
> >         struct cond_insertf_data *data = ptr;
> >         struct policydb *p = data->p;
> > -       struct cond_av_list *other = data->other, *list, *cur;
> >         struct avtab_node *node_ptr;
> > -       u8 found;
> > -       int rc = -EINVAL;
> > +       u32 i;
> > +       bool found;
> >
> >         /*
> >          * For type rules we have to make certain there aren't any
> > @@ -277,7 +269,7 @@ static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum
> >         if (k->specified & AVTAB_TYPE) {
> >                 if (avtab_search(&p->te_avtab, k)) {
> >                         pr_err("SELinux: type rule already exists outside of a conditional.\n");
> > -                       goto err;
> > +                       return -EINVAL;
> >                 }
> >                 /*
> >                  * If we are reading the false list other will be a pointer to
> > @@ -287,29 +279,29 @@ static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum
> >                  * If we are reading the true list (other == NULL) there shouldn't
> >                  * be any other entries.
> >                  */
> > -               if (other) {
> > +               if (data->other) {
> >                         node_ptr = avtab_search_node(&p->te_cond_avtab, k);
> >                         if (node_ptr) {
> >                                 if (avtab_search_node_next(node_ptr, k->specified)) {
> >                                         pr_err("SELinux: too many conflicting type rules.\n");
> > -                                       goto err;
> > +                                       return -EINVAL;
> >                                 }
> > -                               found = 0;
> > -                               for (cur = other; cur; cur = cur->next) {
> > -                                       if (cur->node == node_ptr) {
> > -                                               found = 1;
> > +                               found = false;
> > +                               for (i = 0; i < data->other->len; i++) {
> > +                                       if (data->other->nodes[i] == node_ptr) {
> > +                                               found = true;
> >                                                 break;
> >                                         }
> >                                 }
>
> Can you explain why you got rid of the "other" variable in this
> function?  It seems like it would be nice in the loop above.

It's probably a result of incremental edits... I agree it looks a bit
nicer with it and it also makes the diff simpler. I'll put it back in
v3.
diff mbox series

Patch

diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
index c8a02c9b23ee..b847fd2a6a51 100644
--- a/security/selinux/ss/conditional.c
+++ b/security/selinux/ss/conditional.c
@@ -87,8 +87,9 @@  static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr)
  */
 void evaluate_cond_node(struct policydb *p, struct cond_node *node)
 {
+	struct avtab_node *avnode;
 	int new_state;
-	struct cond_av_list *cur;
+	u32 i;
 
 	new_state = cond_evaluate_expr(p, node->expr);
 	if (new_state != node->cur_state) {
@@ -96,19 +97,21 @@  void evaluate_cond_node(struct policydb *p, struct cond_node *node)
 		if (new_state == -1)
 			pr_err("SELinux: expression result was undefined - disabling all rules.\n");
 		/* turn the rules on or off */
-		for (cur = node->true_list; cur; cur = cur->next) {
+		for (i = 0; i < node->true_list.len; i++) {
+			avnode = node->true_list.nodes[i];
 			if (new_state <= 0)
-				cur->node->key.specified &= ~AVTAB_ENABLED;
+				avnode->key.specified &= ~AVTAB_ENABLED;
 			else
-				cur->node->key.specified |= AVTAB_ENABLED;
+				avnode->key.specified |= AVTAB_ENABLED;
 		}
 
-		for (cur = node->false_list; cur; cur = cur->next) {
+		for (i = 0; i < node->false_list.len; i++) {
+			avnode = node->false_list.nodes[i];
 			/* -1 or 1 */
 			if (new_state)
-				cur->node->key.specified &= ~AVTAB_ENABLED;
+				avnode->key.specified &= ~AVTAB_ENABLED;
 			else
-				cur->node->key.specified |= AVTAB_ENABLED;
+				avnode->key.specified |= AVTAB_ENABLED;
 		}
 	}
 }
@@ -128,16 +131,6 @@  int cond_policydb_init(struct policydb *p)
 	return 0;
 }
 
-static void cond_av_list_destroy(struct cond_av_list *list)
-{
-	struct cond_av_list *cur, *next;
-	for (cur = list; cur; cur = next) {
-		next = cur->next;
-		/* the avtab_ptr_t node is destroy by the avtab */
-		kfree(cur);
-	}
-}
-
 static void cond_node_destroy(struct cond_node *node)
 {
 	struct cond_expr *cur_expr, *next_expr;
@@ -146,8 +139,9 @@  static void cond_node_destroy(struct cond_node *node)
 		next_expr = cur_expr->next;
 		kfree(cur_expr);
 	}
-	cond_av_list_destroy(node->true_list);
-	cond_av_list_destroy(node->false_list);
+	/* the avtab_ptr_t nodes are destroyed by the avtab */
+	kfree(node->true_list.nodes);
+	kfree(node->false_list.nodes);
 }
 
 static void cond_list_destroy(struct policydb *p)
@@ -255,19 +249,17 @@  err:
 
 struct cond_insertf_data {
 	struct policydb *p;
+	struct avtab_node **dst;
 	struct cond_av_list *other;
-	struct cond_av_list *head;
-	struct cond_av_list *tail;
 };
 
 static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum *d, void *ptr)
 {
 	struct cond_insertf_data *data = ptr;
 	struct policydb *p = data->p;
-	struct cond_av_list *other = data->other, *list, *cur;
 	struct avtab_node *node_ptr;
-	u8 found;
-	int rc = -EINVAL;
+	u32 i;
+	bool found;
 
 	/*
 	 * For type rules we have to make certain there aren't any
@@ -277,7 +269,7 @@  static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum
 	if (k->specified & AVTAB_TYPE) {
 		if (avtab_search(&p->te_avtab, k)) {
 			pr_err("SELinux: type rule already exists outside of a conditional.\n");
-			goto err;
+			return -EINVAL;
 		}
 		/*
 		 * If we are reading the false list other will be a pointer to
@@ -287,29 +279,29 @@  static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum
 		 * If we are reading the true list (other == NULL) there shouldn't
 		 * be any other entries.
 		 */
-		if (other) {
+		if (data->other) {
 			node_ptr = avtab_search_node(&p->te_cond_avtab, k);
 			if (node_ptr) {
 				if (avtab_search_node_next(node_ptr, k->specified)) {
 					pr_err("SELinux: too many conflicting type rules.\n");
-					goto err;
+					return -EINVAL;
 				}
-				found = 0;
-				for (cur = other; cur; cur = cur->next) {
-					if (cur->node == node_ptr) {
-						found = 1;
+				found = false;
+				for (i = 0; i < data->other->len; i++) {
+					if (data->other->nodes[i] == node_ptr) {
+						found = true;
 						break;
 					}
 				}
 				if (!found) {
 					pr_err("SELinux: conflicting type rules.\n");
-					goto err;
+					return -EINVAL;
 				}
 			}
 		} else {
 			if (avtab_search(&p->te_cond_avtab, k)) {
 				pr_err("SELinux: conflicting type rules when adding type rule for true.\n");
-				goto err;
+				return -EINVAL;
 			}
 		}
 	}
@@ -317,39 +309,22 @@  static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum
 	node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
 	if (!node_ptr) {
 		pr_err("SELinux: could not insert rule.\n");
-		rc = -ENOMEM;
-		goto err;
-	}
-
-	list = kzalloc(sizeof(*list), GFP_KERNEL);
-	if (!list) {
-		rc = -ENOMEM;
-		goto err;
+		return -ENOMEM;
 	}
 
-	list->node = node_ptr;
-	if (!data->head)
-		data->head = list;
-	else
-		data->tail->next = list;
-	data->tail = list;
+	*data->dst = node_ptr;
 	return 0;
-
-err:
-	cond_av_list_destroy(data->head);
-	data->head = NULL;
-	return rc;
 }
 
-static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list, struct cond_av_list *other)
+static int cond_read_av_list(struct policydb *p, void *fp,
+			     struct cond_av_list *list,
+			     struct cond_av_list *other)
 {
-	int i, rc;
+	int rc;
 	__le32 buf[1];
-	u32 len;
+	u32 i, len;
 	struct cond_insertf_data data;
 
-	*ret_list = NULL;
-
 	rc = next_entry(buf, fp, sizeof(u32));
 	if (rc)
 		return rc;
@@ -358,18 +333,24 @@  static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list *
 	if (len == 0)
 		return 0;
 
+	list->nodes = kcalloc(len, sizeof(*list->nodes), GFP_KERNEL);
+	if (!list->nodes)
+		return -ENOMEM;
+
 	data.p = p;
 	data.other = other;
-	data.head = NULL;
-	data.tail = NULL;
 	for (i = 0; i < len; i++) {
+		data.dst = &list->nodes[i];
 		rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
 				     &data);
-		if (rc)
+		if (rc) {
+			kfree(list->nodes);
+			list->nodes = NULL;
 			return rc;
+		}
 	}
 
-	*ret_list = data.head;
+	list->len = len;
 	return 0;
 }
 
@@ -432,7 +413,7 @@  static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
 	rc = cond_read_av_list(p, fp, &node->true_list, NULL);
 	if (rc)
 		goto err;
-	rc = cond_read_av_list(p, fp, &node->false_list, node->true_list);
+	rc = cond_read_av_list(p, fp, &node->false_list, &node->true_list);
 	if (rc)
 		goto err;
 	return 0;
@@ -511,24 +492,16 @@  static int cond_write_av_list(struct policydb *p,
 			      struct cond_av_list *list, struct policy_file *fp)
 {
 	__le32 buf[1];
-	struct cond_av_list *cur_list;
-	u32 len;
+	u32 i;
 	int rc;
 
-	len = 0;
-	for (cur_list = list; cur_list != NULL; cur_list = cur_list->next)
-		len++;
-
-	buf[0] = cpu_to_le32(len);
+	buf[0] = cpu_to_le32(list->len);
 	rc = put_entry(buf, sizeof(u32), 1, fp);
 	if (rc)
 		return rc;
 
-	if (len == 0)
-		return 0;
-
-	for (cur_list = list; cur_list != NULL; cur_list = cur_list->next) {
-		rc = avtab_write_item(p, cur_list->node, fp);
+	for (i = 0; i < list->len; i++) {
+		rc = avtab_write_item(p, list->nodes[i], fp);
 		if (rc)
 			return rc;
 	}
@@ -565,10 +538,10 @@  static int cond_write_node(struct policydb *p, struct cond_node *node,
 			return rc;
 	}
 
-	rc = cond_write_av_list(p, node->true_list, fp);
+	rc = cond_write_av_list(p, &node->true_list, fp);
 	if (rc)
 		return rc;
-	rc = cond_write_av_list(p, node->false_list, fp);
+	rc = cond_write_av_list(p, &node->false_list, fp);
 	if (rc)
 		return rc;
 
diff --git a/security/selinux/ss/conditional.h b/security/selinux/ss/conditional.h
index e474bdd3a0ed..5f97f678440e 100644
--- a/security/selinux/ss/conditional.h
+++ b/security/selinux/ss/conditional.h
@@ -39,8 +39,8 @@  struct cond_expr {
  * struct is for that list.
  */
 struct cond_av_list {
-	struct avtab_node *node;
-	struct cond_av_list *next;
+	struct avtab_node **nodes;
+	u32 len;
 };
 
 /*
@@ -53,8 +53,8 @@  struct cond_av_list {
 struct cond_node {
 	int cur_state;
 	struct cond_expr *expr;
-	struct cond_av_list *true_list;
-	struct cond_av_list *false_list;
+	struct cond_av_list true_list;
+	struct cond_av_list false_list;
 };
 
 int cond_policydb_init(struct policydb *p);