diff options
| author | Jann Horn <jannh@google.com> | 2016-06-01 11:55:06 +0200 |
|---|---|---|
| committer | Min Chong <mchong@google.com> | 2016-07-25 13:03:32 -0700 |
| commit | ed23e1145053fb43639a178e89e99bb14f11272b (patch) | |
| tree | c603dd891195e20278768457e8f7f8b39b44e2a2 /fs | |
| parent | 53c39433d5fd7d71bec7e904a6fa6691a9e90fdc (diff) | |
UPSTREAM: ecryptfs: forbid opening files without mmap handler
(cherry picked from commit 2f36db71009304b3f0b95afacd8eba1f9f046b87)
This prevents users from triggering a stack overflow through a recursive
invocation of pagefault handling that involves mapping procfs files into
virtual memory.
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Tyler Hicks <tyhicks@canonical.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: I0be77c7f8bd3046bc34cd87ef577529792d479bc
Bug: 29444228
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ecryptfs/kthread.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/fs/ecryptfs/kthread.c b/fs/ecryptfs/kthread.c index 866bb18efefe..e818f5ac7a26 100644 --- a/fs/ecryptfs/kthread.c +++ b/fs/ecryptfs/kthread.c @@ -25,6 +25,7 @@ #include <linux/slab.h> #include <linux/wait.h> #include <linux/mount.h> +#include <linux/file.h> #include "ecryptfs_kernel.h" struct ecryptfs_open_req { @@ -147,7 +148,7 @@ int ecryptfs_privileged_open(struct file **lower_file, flags |= IS_RDONLY(d_inode(lower_dentry)) ? O_RDONLY : O_RDWR; (*lower_file) = dentry_open(&req.path, flags, cred); if (!IS_ERR(*lower_file)) - goto out; + goto have_file; if ((flags & O_ACCMODE) == O_RDONLY) { rc = PTR_ERR((*lower_file)); goto out; @@ -165,8 +166,16 @@ int ecryptfs_privileged_open(struct file **lower_file, mutex_unlock(&ecryptfs_kthread_ctl.mux); wake_up(&ecryptfs_kthread_ctl.wait); wait_for_completion(&req.done); - if (IS_ERR(*lower_file)) + if (IS_ERR(*lower_file)) { rc = PTR_ERR(*lower_file); + goto out; + } +have_file: + if ((*lower_file)->f_op->mmap == NULL) { + fput(*lower_file); + *lower_file = NULL; + rc = -EMEDIUMTYPE; + } out: return rc; } |