forbid_api.c

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#include "forbid_api.h"
 
#include "config.h"
#include "ulist.h"
 
struct ulist forbid_list;
 
int forbid_init(void) {
    int ret;
 
    ulist_init(&forbid_list, FORBID_CFG_FILE);
    ret = ulist_load(&forbid_list);
    if (ret < 0)
        return ret;
 
    return SUCCESS;
}
 
void forbid_exit(void) {
    ulist_save(&forbid_list);
    ulist_clear(&forbid_list);
}
 
int forbid_file(const char *path) {
    int ret;
    char modpath[256];
 
    if (strcmp(path, "/") == 0)
        return -EINVAL;
 
    if (strlen(path) >= sizeof(modpath))
        return -ENAMETOOLONG;
    strscpy(modpath, path, sizeof(modpath));
 
    size_t len = strlen(modpath);
    if (len > 1 && modpath[len - 1] == '/') {
        modpath[len - 1] = '\0';
    }
 
    ret = ulist_add(&forbid_list, modpath, 0, NULL);
    if (ret < 0)
        return ret;
 
    ret = ulist_save(&forbid_list);
    if (ret < 0)
        return ret;
 
    return SUCCESS;
}
 
int unforbid_file(const char *path) {
    int ret;
 
    ret = ulist_remove(&forbid_list, path);
    if (ret < 0)
        return ret;
 
    ret = ulist_save(&forbid_list);
    if (ret < 0)
        return ret;
 
    return SUCCESS;
}
 
static char *get_abs_path(const char __user *u_path, char *buf, int buflen) {
    struct path path;
    char *full;
    int err;
 
    err = user_path_at(AT_FDCWD, u_path, LOOKUP_FOLLOW, &path);
    if (err)
        return NULL;
 
    full = d_path(&path, buf, buflen);
    path_put(&path);
    if (IS_ERR(full))
        return NULL;
    return full;
}
 
int forbid_contains(const char __user *u_path) {
    char *buf;
    char *full;
    int blocked = 0;
 
    if (!u_path)
        return 0;
 
    buf = kmalloc(PATH_MAX, GFP_KERNEL);
    if (!buf)
        return 0;
 
    full = get_abs_path(u_path, buf, PATH_MAX);
    if (full) {
        blocked = ulist_contains(&forbid_list, full);
    }
 
    kfree(buf);
    return blocked;
}
 
int forbid_contains_str(const char *k_path) {
    return ulist_contains(&forbid_list, k_path);
}
 
int forbid_list_get(char *buf, size_t buf_size) {
    return ulist_list(&forbid_list, buf, buf_size);
}