eCryptfs: check for eCryptfs cipher support at mount

[firefly-linux-kernel-4.4.55.git] / fs / ecryptfs / miscdev.c

diff --git a/fs/ecryptfs/miscdev.c b/fs/ecryptfs/miscdev.c
index 940a82e63dc3fcdc52797f9176842fdbf391d272..de42310cd4fb0deb851cca566ff4fb51fbed9b48 100644 (file)
--- a/fs/ecryptfs/miscdev.c
+++ b/fs/ecryptfs/miscdev.c
@@ -49,7 +49,10 @@ ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
        mutex_lock(&ecryptfs_daemon_hash_mux);
        /* TODO: Just use file->private_data? */
        rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
-       BUG_ON(rc || !daemon);
+       if (rc || !daemon) {
+               mutex_unlock(&ecryptfs_daemon_hash_mux);
+               return -EINVAL;
+       }
        mutex_lock(&daemon->mux);
        mutex_unlock(&ecryptfs_daemon_hash_mux);
        if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
@@ -122,6 +125,7 @@ ecryptfs_miscdev_open(struct inode *inode, struct file *file)
                goto out_unlock_daemon;
        }
        daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
+       file->private_data = daemon;
        atomic_inc(&ecryptfs_num_miscdev_opens);
 out_unlock_daemon:
        mutex_unlock(&daemon->mux);
@@ -152,9 +156,9 @@ ecryptfs_miscdev_release(struct inode *inode, struct file *file)
 
        mutex_lock(&ecryptfs_daemon_hash_mux);
        rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
-       BUG_ON(rc || !daemon);
+       if (rc || !daemon)
+               daemon = file->private_data;
        mutex_lock(&daemon->mux);
-       BUG_ON(daemon->pid != task_pid(current));
        BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
        daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
        atomic_dec(&ecryptfs_num_miscdev_opens);
@@ -191,31 +195,32 @@ int ecryptfs_send_miscdev(char *data, size_t data_size,
                          struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
                          u16 msg_flags, struct ecryptfs_daemon *daemon)
 {
-       int rc = 0;
+       struct ecryptfs_message *msg;
 
-       mutex_lock(&msg_ctx->mux);
-       msg_ctx->msg = kmalloc((sizeof(*msg_ctx->msg) + data_size),
-                              GFP_KERNEL);
-       if (!msg_ctx->msg) {
-               rc = -ENOMEM;
+       msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
+       if (!msg) {
                printk(KERN_ERR "%s: Out of memory whilst attempting "
                       "to kmalloc(%zd, GFP_KERNEL)\n", __func__,
-                      (sizeof(*msg_ctx->msg) + data_size));
-               goto out_unlock;
+                      (sizeof(*msg) + data_size));
+               return -ENOMEM;
        }
+
+       mutex_lock(&msg_ctx->mux);
+       msg_ctx->msg = msg;
        msg_ctx->msg->index = msg_ctx->index;
        msg_ctx->msg->data_len = data_size;
        msg_ctx->type = msg_type;
        memcpy(msg_ctx->msg->data, data, data_size);
        msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
-       mutex_lock(&daemon->mux);
        list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
+       mutex_unlock(&msg_ctx->mux);
+
+       mutex_lock(&daemon->mux);
        daemon->num_queued_msg_ctx++;
        wake_up_interruptible(&daemon->wait);
        mutex_unlock(&daemon->mux);
-out_unlock:
-       mutex_unlock(&msg_ctx->mux);
-       return rc;
+
+       return 0;
 }
 
 /**
@@ -246,8 +251,16 @@ ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
        mutex_lock(&ecryptfs_daemon_hash_mux);
        /* TODO: Just use file->private_data? */
        rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
-       BUG_ON(rc || !daemon);
+       if (rc || !daemon) {
+               mutex_unlock(&ecryptfs_daemon_hash_mux);
+               return -EINVAL;
+       }
        mutex_lock(&daemon->mux);
+       if (task_pid(current) != daemon->pid) {
+               mutex_unlock(&daemon->mux);
+               mutex_unlock(&ecryptfs_daemon_hash_mux);
+               return -EPERM;
+       }
        if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
                rc = 0;
                mutex_unlock(&ecryptfs_daemon_hash_mux);
@@ -284,9 +297,6 @@ check_list:
                 * message from the queue; try again */
                goto check_list;
        }
-       BUG_ON(euid != daemon->euid);
-       BUG_ON(current_user_ns() != daemon->user_ns);
-       BUG_ON(task_pid(current) != daemon->pid);
        msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
                                   struct ecryptfs_msg_ctx, daemon_out_list);
        BUG_ON(!msg_ctx);
@@ -409,11 +419,47 @@ ecryptfs_miscdev_write(struct file *file, const char __user *buf,
        ssize_t sz = 0;
        char *data;
        uid_t euid = current_euid();
+       unsigned char packet_size_peek[3];
        int rc;
 
-       if (count == 0)
+       if (count == 0) {
                goto out;
+       } else if (count == (1 + 4)) {
+               /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
+               goto memdup;
+       } else if (count < (1 + 4 + 1)
+                  || count > (1 + 4 + 2 + sizeof(struct ecryptfs_message) + 4
+                              + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)) {
+               printk(KERN_WARNING "%s: Acceptable packet size range is "
+                      "[%d-%lu], but amount of data written is [%zu].",
+                      __func__, (1 + 4 + 1),
+                      (1 + 4 + 2 + sizeof(struct ecryptfs_message) + 4
+                       + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES), count);
+               return -EINVAL;
+       }
+
+       if (copy_from_user(packet_size_peek, (buf + 1 + 4),
+                          sizeof(packet_size_peek))) {
+               printk(KERN_WARNING "%s: Error while inspecting packet size\n",
+                      __func__);
+               return -EFAULT;
+       }
+
+       rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
+                                         &packet_size_length);
+       if (rc) {
+               printk(KERN_WARNING "%s: Error parsing packet length; "
+                      "rc = [%d]\n", __func__, rc);
+               return rc;
+       }
 
+       if ((1 + 4 + packet_size_length + packet_size) != count) {
+               printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
+                      packet_size);
+               return -EINVAL;
+       }
+
+memdup:
        data = memdup_user(buf, count);
        if (IS_ERR(data)) {
                printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
@@ -435,23 +481,7 @@ ecryptfs_miscdev_write(struct file *file, const char __user *buf,
                }
                memcpy(&counter_nbo, &data[i], 4);
                seq = be32_to_cpu(counter_nbo);
-               i += 4;
-               rc = ecryptfs_parse_packet_length(&data[i], &packet_size,
-                                                 &packet_size_length);
-               if (rc) {
-                       printk(KERN_WARNING "%s: Error parsing packet length; "
-                              "rc = [%d]\n", __func__, rc);
-                       goto out_free;
-               }
-               i += packet_size_length;
-               if ((1 + 4 + packet_size_length + packet_size) != count) {
-                       printk(KERN_WARNING "%s: (1 + packet_size_length([%zd])"
-                              " + packet_size([%zd]))([%zd]) != "
-                              "count([%zd]). Invalid packet format.\n",
-                              __func__, packet_size_length, packet_size,
-                              (1 + packet_size_length + packet_size), count);
-                       goto out_free;
-               }
+               i += 4 + packet_size_length;
                rc = ecryptfs_miscdev_response(&data[i], packet_size,
                                               euid, current_user_ns(),
                                               task_pid(current), seq);