From 2b3a003e1543ab47b2f150abe31df4e7a3f8dde8 Mon Sep 17 00:00:00 2001 From: Ondrej Mosnacek Date: Mon, 3 Feb 2020 12:27:21 +0100 Subject: [PATCH] selinux: convert cond_av_list to array 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 Reviewed-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/ss/conditional.c | 124 ++++++++++++------------------ security/selinux/ss/conditional.h | 8 +- 2 files changed, 53 insertions(+), 79 deletions(-) diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c index e6d203b76545..82002b90809c 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 +249,18 @@ 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 cond_av_list *other = data->other; 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 +270,7 @@ 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 @@ -292,24 +285,24 @@ static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum 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 < other->len; i++) { + if (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 +310,22 @@ 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; + return -ENOMEM; } - list = kzalloc(sizeof(*list), GFP_KERNEL); - if (!list) { - rc = -ENOMEM; - goto err; - } - - 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 +334,24 @@ 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 +414,7 @@ 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 +493,16 @@ 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 +539,10 @@ 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);