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Merge tag 'loadpin-v5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

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Pull security/loadpin updates from Kees Cook:

 - Allow exclusion of specific file types (Ke Wu)

* tag 'loadpin-v5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  security/loadpin: Allow to exclude specific file types
This commit is contained in:
Linus Torvalds
2019-07-11 14:42:44 -07:00
parent 6b44fccdb8 0ff9848067
commit c079512aad
2 changed files with 58 additions and 0 deletions
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48
security/loadpin/loadpin.c
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@@ -37,6 +37,8 @@ static void report_load(const char *origin, struct file *file, char *operation)
}
static int enforce = IS_ENABLED(CONFIG_SECURITY_LOADPIN_ENFORCE);
static char *exclude_read_files[READING_MAX_ID];
static int ignore_read_file_id[READING_MAX_ID] __ro_after_init;
static struct super_block *pinned_root;
static DEFINE_SPINLOCK(pinned_root_spinlock);
@@ -121,6 +123,13 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id)
struct super_block *load_root;
const char *origin = kernel_read_file_id_str(id);
/* If the file id is excluded, ignore the pinning. */
if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) &&
ignore_read_file_id[id]) {
report_load(origin, file, "pinning-excluded");
return 0;
}
/* This handles the older init_module API that has a NULL file. */
if (!file) {
if (!enforce) {
@@ -179,10 +188,47 @@ static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(kernel_load_data, loadpin_load_data),
};
static void __init parse_exclude(void)
{
int i, j;
char *cur;
/*
* Make sure all the arrays stay within expected sizes. This
* is slightly weird because kernel_read_file_str[] includes
* READING_MAX_ID, which isn't actually meaningful here.
*/
BUILD_BUG_ON(ARRAY_SIZE(exclude_read_files) !=
ARRAY_SIZE(ignore_read_file_id));
BUILD_BUG_ON(ARRAY_SIZE(kernel_read_file_str) <
ARRAY_SIZE(ignore_read_file_id));
for (i = 0; i < ARRAY_SIZE(exclude_read_files); i++) {
cur = exclude_read_files[i];
if (!cur)
break;
if (*cur == '\0')
continue;
for (j = 0; j < ARRAY_SIZE(ignore_read_file_id); j++) {
if (strcmp(cur, kernel_read_file_str[j]) == 0) {
pr_info("excluding: %s\n",
kernel_read_file_str[j]);
ignore_read_file_id[j] = 1;
/*
* Can not break, because one read_file_str
* may map to more than on read_file_id.
*/
}
}
}
}
static int __init loadpin_init(void)
{
pr_info("ready to pin (currently %senforcing)\n",
enforce ? "" : "not ");
parse_exclude();
security_add_hooks(loadpin_hooks, ARRAY_SIZE(loadpin_hooks), "loadpin");
return 0;
}
@@ -195,3 +241,5 @@ DEFINE_LSM(loadpin) = {
/* Should not be mutable after boot, so not listed in sysfs (perm == 0). */
module_param(enforce, int, 0);
MODULE_PARM_DESC(enforce, "Enforce module/firmware pinning");
module_param_array_named(exclude, exclude_read_files, charp, NULL, 0);
MODULE_PARM_DESC(exclude, "Exclude pinning specific read file types");