Home Home > GIT Browse
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorTyler Hicks <tyhicks@canonical.com>2012-06-11 09:24:11 -0700
committerTyler Hicks <tyhicks@canonical.com>2012-07-06 15:51:12 -0500
commit8dc6780587c99286c0d3de747a2946a76989414a (patch)
treed553ed49a104387f898bc93bc226821b83d49583
parent60d65f1f07a7d81d3eb3b91fc13fca80f2fdbb12 (diff)
eCryptfs: Gracefully refuse miscdev file ops on inherited/passed files
File operations on /dev/ecryptfs would BUG() when the operations were performed by processes other than the process that originally opened the file. This could happen with open files inherited after fork() or file descriptors passed through IPC mechanisms. Rather than calling BUG(), an error code can be safely returned in most situations. In ecryptfs_miscdev_release(), eCryptfs still needs to handle the release even if the last file reference is being held by a process that didn't originally open the file. ecryptfs_find_daemon_by_euid() will not be successful, so a pointer to the daemon is stored in the file's private_data. The private_data pointer is initialized when the miscdev file is opened and only used when the file is released. https://launchpad.net/bugs/994247 Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Reported-by: Sasha Levin <levinsasha928@gmail.com> Tested-by: Sasha Levin <levinsasha928@gmail.com>
-rw-r--r--fs/ecryptfs/miscdev.c23
1 files changed, 16 insertions, 7 deletions
diff --git a/fs/ecryptfs/miscdev.c b/fs/ecryptfs/miscdev.c
index 3c632ec412ec..c0038f6566d4 100644
--- 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);
@@ -270,8 +274,16 @@ 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);
@@ -308,9 +320,6 @@ 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);