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-rw-r--r--fs/sdcardfs/packagelist.c453
1 files changed, 453 insertions, 0 deletions
diff --git a/fs/sdcardfs/packagelist.c b/fs/sdcardfs/packagelist.c
new file mode 100644
index 00000000..183fb14d
--- /dev/null
+++ b/fs/sdcardfs/packagelist.c
@@ -0,0 +1,453 @@
+/*
+ * fs/sdcardfs/packagelist.c
+ *
+ * Copyright (c) 2013 Samsung Electronics Co. Ltd
+ * Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
+ * Sunghwan Yun, Sungjong Seo
+ *
+ * This program has been developed as a stackable file system based on
+ * the WrapFS which written by
+ *
+ * Copyright (c) 1998-2011 Erez Zadok
+ * Copyright (c) 2009 Shrikar Archak
+ * Copyright (c) 2003-2011 Stony Brook University
+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
+ *
+ * This file is dual licensed. It may be redistributed and/or modified
+ * under the terms of the Apache 2.0 License OR version 2 of the GNU
+ * General Public License.
+ */
+
+#include "sdcardfs.h"
+#include "strtok.h"
+#include <linux/hashtable.h>
+#include <linux/syscalls.h>
+#include <linux/kthread.h>
+#include <linux/inotify.h>
+#include <linux/delay.h>
+
+#define STRING_BUF_SIZE (512)
+
+struct hashtable_entry {
+ struct hlist_node hlist;
+ void *key;
+ int value;
+};
+
+struct packagelist_data {
+ DECLARE_HASHTABLE(package_to_appid,8);
+ DECLARE_HASHTABLE(appid_with_rw,7);
+ struct mutex hashtable_lock;
+ struct task_struct *thread_id;
+ gid_t write_gid;
+ char *strtok_last;
+ char read_buf[STRING_BUF_SIZE];
+ char event_buf[STRING_BUF_SIZE];
+ char app_name_buf[STRING_BUF_SIZE];
+ char gids_buf[STRING_BUF_SIZE];
+};
+
+static struct kmem_cache *hashtable_entry_cachep;
+
+/* Path to system-provided mapping of package name to appIds */
+static const char* const kpackageslist_file = "/data/system/packages.list";
+/* Supplementary groups to execute with */
+static const gid_t kgroups[1] = { AID_PACKAGE_INFO };
+
+static unsigned int str_hash(void *key) {
+ int i;
+ unsigned int h = strlen(key);
+ char *data = (char *)key;
+
+ for (i = 0; i < strlen(key); i++) {
+ h = h * 31 + *data;
+ data++;
+ }
+ return h;
+}
+
+static int contain_appid_key(struct packagelist_data *pkgl_dat, void *appid) {
+ struct hashtable_entry *hash_cur;
+
+ hash_for_each_possible(pkgl_dat->appid_with_rw, hash_cur, hlist, (unsigned int)appid)
+ if (appid == hash_cur->key)
+ return 1;
+ return 0;
+}
+
+/* Return if the calling UID holds sdcard_rw. */
+int get_caller_has_rw_locked(void *pkgl_id, derive_t derive) {
+ struct packagelist_data *pkgl_dat = (struct packagelist_data *)pkgl_id;
+ appid_t appid;
+ int ret;
+
+ /* No additional permissions enforcement */
+ if (derive == DERIVE_NONE) {
+ return 1;
+ }
+
+ appid = multiuser_get_app_id(current_fsuid());
+ mutex_lock(&pkgl_dat->hashtable_lock);
+ ret = contain_appid_key(pkgl_dat, (void *)appid);
+ mutex_unlock(&pkgl_dat->hashtable_lock);
+ //printk(KERN_INFO "sdcardfs: %s: appid=%d, ret=%d\n", __func__, (int)appid, ret);
+ return ret;
+}
+
+appid_t get_appid(void *pkgl_id, const char *app_name)
+{
+ struct packagelist_data *pkgl_dat = (struct packagelist_data *)pkgl_id;
+ struct hashtable_entry *hash_cur;
+ unsigned int hash = str_hash((void *)app_name);
+ appid_t ret_id;
+
+ //printk(KERN_INFO "sdcardfs: %s: %s, %u\n", __func__, (char *)app_name, hash);
+ mutex_lock(&pkgl_dat->hashtable_lock);
+ hash_for_each_possible(pkgl_dat->package_to_appid, hash_cur, hlist, hash) {
+ //printk(KERN_INFO "sdcardfs: %s: %s\n", __func__, (char *)hash_cur->key);
+ if (!strcasecmp(app_name, hash_cur->key)) {
+ ret_id = (appid_t)hash_cur->value;
+ mutex_unlock(&pkgl_dat->hashtable_lock);
+ //printk(KERN_INFO "=> app_id: %d\n", (int)ret_id);
+ return ret_id;
+ }
+ }
+ mutex_unlock(&pkgl_dat->hashtable_lock);
+ //printk(KERN_INFO "=> app_id: %d\n", 0);
+ return 0;
+}
+
+/* Kernel has already enforced everything we returned through
+ * derive_permissions_locked(), so this is used to lock down access
+ * even further, such as enforcing that apps hold sdcard_rw. */
+int check_caller_access_to_name(struct inode *parent_node, const char* name,
+ derive_t derive, int w_ok, int has_rw) {
+
+ /* Always block security-sensitive files at root */
+ if (parent_node && SDCARDFS_I(parent_node)->perm == PERM_ROOT) {
+ if (!strcasecmp(name, "autorun.inf")
+ || !strcasecmp(name, ".android_secure")
+ || !strcasecmp(name, "android_secure")) {
+ return 0;
+ }
+ }
+
+ /* No additional permissions enforcement */
+ if (derive == DERIVE_NONE) {
+ return 1;
+ }
+
+ /* Root always has access; access for any other UIDs should always
+ * be controlled through packages.list. */
+ if (current_fsuid() == 0) {
+ return 1;
+ }
+
+ /* If asking to write, verify that caller either owns the
+ * parent or holds sdcard_rw. */
+ if (w_ok) {
+ if (parent_node &&
+ (current_fsuid() == SDCARDFS_I(parent_node)->d_uid)) {
+ return 1;
+ }
+ return has_rw;
+ }
+
+ /* No extra permissions to enforce */
+ return 1;
+}
+
+/* This function is used when file opening. The open flags must be
+ * checked before calling check_caller_access_to_name() */
+int open_flags_to_access_mode(int open_flags) {
+ if((open_flags & O_ACCMODE) == O_RDONLY) {
+ return 0; /* R_OK */
+ } else if ((open_flags & O_ACCMODE) == O_WRONLY) {
+ return 1; /* W_OK */
+ } else {
+ /* Probably O_RDRW, but treat as default to be safe */
+ return 1; /* R_OK | W_OK */
+ }
+}
+
+static int insert_str_to_int(struct packagelist_data *pkgl_dat, void *key, int value) {
+ struct hashtable_entry *hash_cur;
+ struct hashtable_entry *new_entry;
+ unsigned int hash = str_hash(key);
+
+ //printk(KERN_INFO "sdcardfs: %s: %s: %d, %u\n", __func__, (char *)key, value, hash);
+ hash_for_each_possible(pkgl_dat->package_to_appid, hash_cur, hlist, hash) {
+ if (!strcasecmp(key, hash_cur->key)) {
+ hash_cur->value = value;
+ return 0;
+ }
+ }
+ new_entry = kmem_cache_alloc(hashtable_entry_cachep, GFP_KERNEL);
+ if (!new_entry)
+ return -ENOMEM;
+ new_entry->key = kstrdup(key, GFP_KERNEL);
+ new_entry->value = value;
+ hash_add(pkgl_dat->package_to_appid, &new_entry->hlist, hash);
+ return 0;
+}
+
+static void remove_str_to_int(struct hashtable_entry *h_entry) {
+ //printk(KERN_INFO "sdcardfs: %s: %s: %d\n", __func__, (char *)h_entry->key, h_entry->value);
+ kfree(h_entry->key);
+ kmem_cache_free(hashtable_entry_cachep, h_entry);
+}
+
+static int insert_int_to_null(struct packagelist_data *pkgl_dat, void *key, int value) {
+ struct hashtable_entry *hash_cur;
+ struct hashtable_entry *new_entry;
+
+ //printk(KERN_INFO "sdcardfs: %s: %d: %d\n", __func__, (int)key, value);
+ hash_for_each_possible(pkgl_dat->appid_with_rw, hash_cur, hlist, (unsigned int)key) {
+ if (key == hash_cur->key) {
+ hash_cur->value = value;
+ return 0;
+ }
+ }
+ new_entry = kmem_cache_alloc(hashtable_entry_cachep, GFP_KERNEL);
+ if (!new_entry)
+ return -ENOMEM;
+ new_entry->key = key;
+ new_entry->value = value;
+ hash_add(pkgl_dat->appid_with_rw, &new_entry->hlist,
+ (unsigned int)new_entry->key);
+ return 0;
+}
+
+static void remove_int_to_null(struct hashtable_entry *h_entry) {
+ //printk(KERN_INFO "sdcardfs: %s: %d: %d\n", __func__, (int)h_entry->key, h_entry->value);
+ kmem_cache_free(hashtable_entry_cachep, h_entry);
+}
+
+static void remove_all_hashentrys(struct packagelist_data *pkgl_dat)
+{
+ struct hashtable_entry *hash_cur;
+ struct hlist_node *h_t;
+ int i;
+
+ hash_for_each_safe(pkgl_dat->package_to_appid, i, h_t, hash_cur, hlist)
+ remove_str_to_int(hash_cur);
+ hash_for_each_safe(pkgl_dat->appid_with_rw, i, h_t, hash_cur, hlist)
+ remove_int_to_null(hash_cur);
+
+ hash_init(pkgl_dat->package_to_appid);
+ hash_init(pkgl_dat->appid_with_rw);
+}
+
+static int read_package_list(struct packagelist_data *pkgl_dat) {
+ int ret;
+ int fd;
+ int read_amount;
+
+ printk(KERN_INFO "sdcardfs: read_package_list\n");
+
+ mutex_lock(&pkgl_dat->hashtable_lock);
+
+ remove_all_hashentrys(pkgl_dat);
+
+ fd = sys_open(kpackageslist_file, O_RDONLY, 0);
+ if (fd < 0) {
+ printk(KERN_ERR "sdcardfs: failed to open package list\n");
+ mutex_unlock(&pkgl_dat->hashtable_lock);
+ return fd;
+ }
+
+ while ((read_amount = sys_read(fd, pkgl_dat->read_buf,
+ sizeof(pkgl_dat->read_buf))) > 0) {
+ int appid;
+ char *token;
+ int one_line_len = 0;
+ int additional_read;
+ unsigned long ret_gid;
+
+ while (one_line_len < read_amount) {
+ if (pkgl_dat->read_buf[one_line_len] == '\n') {
+ one_line_len++;
+ break;
+ }
+ one_line_len++;
+ }
+ additional_read = read_amount - one_line_len;
+ if (additional_read > 0)
+ sys_lseek(fd, -additional_read, SEEK_CUR);
+
+ if (sscanf(pkgl_dat->read_buf, "%s %d %*d %*s %*s %s",
+ pkgl_dat->app_name_buf, &appid,
+ pkgl_dat->gids_buf) == 3) {
+ ret = insert_str_to_int(pkgl_dat, pkgl_dat->app_name_buf, appid);
+ if (ret) {
+ sys_close(fd);
+ mutex_unlock(&pkgl_dat->hashtable_lock);
+ return ret;
+ }
+
+ token = strtok_r(pkgl_dat->gids_buf, ",", &pkgl_dat->strtok_last);
+ while (token != NULL) {
+ if (!kstrtoul(token, 10, &ret_gid) &&
+ (ret_gid == pkgl_dat->write_gid)) {
+ ret = insert_int_to_null(pkgl_dat, (void *)appid, 1);
+ if (ret) {
+ sys_close(fd);
+ mutex_unlock(&pkgl_dat->hashtable_lock);
+ return ret;
+ }
+ break;
+ }
+ token = strtok_r(NULL, ",", &pkgl_dat->strtok_last);
+ }
+ }
+ }
+
+ sys_close(fd);
+ mutex_unlock(&pkgl_dat->hashtable_lock);
+ return 0;
+}
+
+static int packagelist_reader(void *thread_data)
+{
+ struct packagelist_data *pkgl_dat = (struct packagelist_data *)thread_data;
+ struct inotify_event *event;
+ bool active = false;
+ int event_pos;
+ int event_size;
+ int res = 0;
+ int nfd;
+
+ allow_signal(SIGINT);
+
+ nfd = sys_inotify_init();
+ if (nfd < 0) {
+ printk(KERN_ERR "sdcardfs: inotify_init failed: %d\n", nfd);
+ return nfd;
+ }
+
+ while (!kthread_should_stop()) {
+ if (signal_pending(current)) {
+ ssleep(1);
+ continue;
+ }
+
+ if (!active) {
+ res = sys_inotify_add_watch(nfd, kpackageslist_file, IN_DELETE_SELF);
+ if (res < 0) {
+ if (res == -ENOENT || res == -EACCES) {
+ /* Framework may not have created yet, sleep and retry */
+ printk(KERN_ERR "sdcardfs: missing packages.list; retrying\n");
+ ssleep(2);
+ printk(KERN_ERR "sdcardfs: missing packages.list_end; retrying\n");
+ continue;
+ } else {
+ printk(KERN_ERR "sdcardfs: inotify_add_watch failed: %d\n", res);
+ goto interruptable_sleep;
+ }
+ }
+ /* Watch above will tell us about any future changes, so
+ * read the current state. */
+ res = read_package_list(pkgl_dat);
+ if (res) {
+ printk(KERN_ERR "sdcardfs: read_package_list failed: %d\n", res);
+ goto interruptable_sleep;
+ }
+ active = true;
+ }
+
+ event_pos = 0;
+ res = sys_read(nfd, pkgl_dat->event_buf, sizeof(pkgl_dat->event_buf));
+ if (res < (int) sizeof(*event)) {
+ if (res == -EINTR)
+ continue;
+ printk(KERN_ERR "sdcardfs: failed to read inotify event: %d\n", res);
+ goto interruptable_sleep;
+ }
+
+ while (res >= (int) sizeof(*event)) {
+ event = (struct inotify_event *) (pkgl_dat->event_buf + event_pos);
+
+ printk(KERN_INFO "sdcardfs: inotify event: %08x\n", event->mask);
+ if ((event->mask & IN_IGNORED) == IN_IGNORED) {
+ /* Previously watched file was deleted, probably due to move
+ * that swapped in new data; re-arm the watch and read. */
+ active = false;
+ }
+
+ event_size = sizeof(*event) + event->len;
+ res -= event_size;
+ event_pos += event_size;
+ }
+ continue;
+
+interruptable_sleep:
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule();
+ }
+ flush_signals(current);
+ sys_close(nfd);
+ return res;
+}
+
+void * packagelist_create(gid_t write_gid)
+{
+ struct packagelist_data *pkgl_dat;
+ struct task_struct *packagelist_thread;
+
+ pkgl_dat = kmalloc(sizeof(*pkgl_dat), GFP_KERNEL | __GFP_ZERO);
+ if (!pkgl_dat) {
+ printk(KERN_ERR "sdcardfs: creating kthread failed\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ mutex_init(&pkgl_dat->hashtable_lock);
+ hash_init(pkgl_dat->package_to_appid);
+ hash_init(pkgl_dat->appid_with_rw);
+ pkgl_dat->write_gid = write_gid;
+
+ packagelist_thread = kthread_run(packagelist_reader, (void *)pkgl_dat, "pkgld");
+ if (IS_ERR(packagelist_thread)) {
+ printk(KERN_ERR "sdcardfs: creating kthread failed\n");
+ kfree(pkgl_dat);
+ return packagelist_thread;
+ }
+ pkgl_dat->thread_id = packagelist_thread;
+
+ printk(KERN_INFO "sdcardfs: created packagelist pkgld/%d\n",
+ (int)pkgl_dat->thread_id->pid);
+
+ return (void *)pkgl_dat;
+}
+
+void packagelist_destroy(void *pkgl_id)
+{
+ struct packagelist_data *pkgl_dat = (struct packagelist_data *)pkgl_id;
+ pid_t pkgl_pid = pkgl_dat->thread_id->pid;
+
+ force_sig_info(SIGINT, SEND_SIG_PRIV, pkgl_dat->thread_id);
+ kthread_stop(pkgl_dat->thread_id);
+ remove_all_hashentrys(pkgl_dat);
+ printk(KERN_INFO "sdcardfs: destroyed packagelist pkgld/%d\n", (int)pkgl_pid);
+ kfree(pkgl_dat);
+}
+
+int packagelist_init(void)
+{
+ hashtable_entry_cachep =
+ kmem_cache_create("packagelist_hashtable_entry",
+ sizeof(struct hashtable_entry), 0, 0, NULL);
+ if (!hashtable_entry_cachep) {
+ printk(KERN_ERR "sdcardfs: failed creating pkgl_hashtable entry slab cache\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+void packagelist_exit(void)
+{
+ if (hashtable_entry_cachep)
+ kmem_cache_destroy(hashtable_entry_cachep);
+}
+
+
generated by cgit v1.3.1 (git 2.54.0) at 2026-08-15 13:32:55 +0000