From: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
Utilize cache locality for the substitutions by storing them in
contiguous memory instead of a linked list.
Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
---
v3: fix memleak in err label in selabel_subs_init()
v2: drop unnecessary check for zero length
---
libselinux/src/label_file.c | 129 +++++++++++++++++++-----------------
libselinux/src/label_file.h | 20 ++++--
2 files changed, 83 insertions(+), 66 deletions(-)
diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c
index 4e212aa4..8050ef1a 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -1120,28 +1120,27 @@ static int process_file(const char *path, const char *suffix,
return -1;
}
-static void selabel_subs_fini(struct selabel_sub *ptr)
+static void selabel_subs_fini(struct selabel_sub *subs, uint32_t num)
{
- struct selabel_sub *next;
-
- while (ptr) {
- next = ptr->next;
- free(ptr->src);
- free(ptr->dst);
- free(ptr);
- ptr = next;
+ for (uint32_t i = 0; i < num; i++) {
+ free(subs[i].src);
+ free(subs[i].dst);
}
+
+ free(subs);
}
-static char *selabel_sub(const struct selabel_sub *ptr, const char *src)
+static char *selabel_apply_subs(const struct selabel_sub *subs, uint32_t num, const char *src)
{
- char *dst = NULL;
- unsigned int len;
+ char *dst;
+ uint32_t len;
+
+ for (uint32_t i = 0; i < num; i++) {
+ const struct selabel_sub *ptr = &subs[i];
- while (ptr) {
if (strncmp(src, ptr->src, ptr->slen) == 0 ) {
if (src[ptr->slen] == '/' ||
- src[ptr->slen] == 0) {
+ src[ptr->slen] == '\0') {
if ((src[ptr->slen] == '/') &&
(strcmp(ptr->dst, "/") == 0))
len = ptr->slen + 1;
@@ -1152,34 +1151,38 @@ static char *selabel_sub(const struct selabel_sub *ptr, const char *src)
return dst;
}
}
- ptr = ptr->next;
}
+
return NULL;
}
#if !defined(BUILD_HOST) && !defined(ANDROID)
static int selabel_subs_init(const char *path, struct selabel_digest *digest,
- struct selabel_sub **out_subs)
+ struct selabel_sub **out_subs,
+ uint32_t *out_num, uint32_t *out_alloc)
{
char buf[1024];
- FILE *cfg = fopen(path, "re");
- struct selabel_sub *list = NULL, *sub = NULL;
+ FILE *cfg;
struct stat sb;
- int status = -1;
+ struct selabel_sub *tmp = NULL;
+ uint32_t tmp_num = 0, tmp_alloc = 0;
+ char *src_cpy = NULL, *dst_cpy = NULL;
+ int rc;
*out_subs = NULL;
+ *out_num = 0;
+ *out_alloc = 0;
+
+ cfg = fopen(path, "re");
if (!cfg) {
/* If the file does not exist, it is not fatal */
return (errno == ENOENT) ? 0 : -1;
}
- if (fstat(fileno(cfg), &sb) < 0)
- goto out;
-
while (fgets_unlocked(buf, sizeof(buf) - 1, cfg)) {
- char *ptr = NULL;
+ char *ptr;
char *src = buf;
- char *dst = NULL;
+ char *dst;
size_t len;
while (*src && isspace((unsigned char)*src))
@@ -1207,62 +1210,68 @@ static int selabel_subs_init(const char *path, struct selabel_digest *digest,
goto err;
}
- sub = calloc(1, sizeof(*sub));
- if (! sub)
+ src_cpy = strdup(src);
+ if (!src_cpy)
goto err;
- sub->src = strdup(src);
- if (! sub->src)
+ dst_cpy = strdup(dst);
+ if (!dst_cpy)
goto err;
- sub->dst = strdup(dst);
- if (! sub->dst)
+ rc = GROW_ARRAY(tmp);
+ if (rc)
goto err;
- sub->slen = len;
- sub->next = list;
- list = sub;
- sub = NULL;
+ tmp[tmp_num++] = (struct selabel_sub) {
+ .src = src_cpy,
+ .slen = len,
+ .dst = dst_cpy,
+ };
+ src_cpy = NULL;
+ dst_cpy = NULL;
}
+ rc = fstat(fileno(cfg), &sb);
+ if (rc < 0)
+ goto err;
+
if (digest_add_specfile(digest, cfg, NULL, sb.st_size, path) < 0)
goto err;
- *out_subs = list;
- status = 0;
+ *out_subs = tmp;
+ *out_num = tmp_num;
+ *out_alloc = tmp_alloc;
-out:
fclose(cfg);
- return status;
+
+ return 0;
+
err:
- if (sub)
- free(sub->src);
- free(sub);
- while (list) {
- sub = list->next;
- free(list->src);
- free(list->dst);
- free(list);
- list = sub;
+ free(dst_cpy);
+ free(src_cpy);
+ for (uint32_t i = 0; i < tmp_num; i++) {
+ free(tmp[i].src);
+ free(tmp[i].dst);
}
- goto out;
+ free(tmp);
+ fclose_errno_safe(cfg);
+ return -1;
}
#endif
static char *selabel_sub_key(const struct saved_data *data, const char *key)
{
- char *ptr = NULL;
- char *dptr = NULL;
+ char *ptr, *dptr;
- ptr = selabel_sub(data->subs, key);
+ ptr = selabel_apply_subs(data->subs, data->subs_num, key);
if (ptr) {
- dptr = selabel_sub(data->dist_subs, ptr);
+ dptr = selabel_apply_subs(data->dist_subs, data->dist_subs_num, ptr);
if (dptr) {
free(ptr);
ptr = dptr;
}
} else {
- ptr = selabel_sub(data->dist_subs, key);
+ ptr = selabel_apply_subs(data->dist_subs, data->dist_subs_num, key);
}
return ptr;
@@ -1307,23 +1316,25 @@ static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
if (!path) {
status = selabel_subs_init(
selinux_file_context_subs_dist_path(),
- rec->digest, &data->dist_subs);
+ rec->digest,
+ &data->dist_subs, &data->dist_subs_num, &data->dist_subs_alloc);
if (status)
goto finish;
status = selabel_subs_init(selinux_file_context_subs_path(),
- rec->digest, &data->subs);
+ rec->digest,
+ &data->subs, &data->subs_num, &data->subs_alloc);
if (status)
goto finish;
path = selinux_file_context_path();
} else {
snprintf(subs_file, sizeof(subs_file), "%s.subs_dist", path);
status = selabel_subs_init(subs_file, rec->digest,
- &data->dist_subs);
+ &data->dist_subs, &data->dist_subs_num, &data->dist_subs_alloc);
if (status)
goto finish;
snprintf(subs_file, sizeof(subs_file), "%s.subs", path);
status = selabel_subs_init(subs_file, rec->digest,
- &data->subs);
+ &data->subs, &data->subs_num, &data->subs_alloc);
if (status)
goto finish;
}
@@ -1391,8 +1402,8 @@ static void closef(struct selabel_handle *rec)
if (!data)
return;
- selabel_subs_fini(data->subs);
- selabel_subs_fini(data->dist_subs);
+ selabel_subs_fini(data->subs, data->subs_num);
+ selabel_subs_fini(data->dist_subs, data->dist_subs_num);
free_spec_node(data->root);
free(data->root);
diff --git a/libselinux/src/label_file.h b/libselinux/src/label_file.h
index de8190f9..436982bf 100644
--- a/libselinux/src/label_file.h
+++ b/libselinux/src/label_file.h
@@ -67,11 +67,11 @@ extern struct lookup_result *lookup_all(struct selabel_handle *rec, const char *
extern enum selabel_cmp_result cmp(const struct selabel_handle *h1, const struct selabel_handle *h2);
#endif /* FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
+/* A path substitution entry */
struct selabel_sub {
- char *src;
- unsigned int slen;
- char *dst;
- struct selabel_sub *next;
+ char *src; /* source path prefix */
+ char *dst; /* substituted path prefix */
+ uint32_t slen; /* length of source path prefix */
};
/* A regular expression file security context specification */
@@ -159,9 +159,17 @@ struct saved_data {
struct mmap_area *mmap_areas;
- /* substitution support */
+ /*
+ * Array of distribution substitutions
+ */
struct selabel_sub *dist_subs;
+ uint32_t dist_subs_num, dist_subs_alloc;
+
+ /*
+ * Array of local substitutions
+ */
struct selabel_sub *subs;
+ uint32_t subs_num, subs_alloc;
};
static inline mode_t string_to_file_kind(const char *mode)
@@ -811,8 +819,6 @@ static int insert_spec(const struct selabel_handle *rec, struct saved_data *data
return 0;
}
-#undef GROW_ARRAY
-
static inline void free_spec_node(struct spec_node *node)
{
for (uint32_t i = 0; i < node->literal_specs_num; i++) {
--
2.45.2
