diff options
| author | Jann Horn <jannh@google.com> | 2016-06-01 11:55:06 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-06-10 21:09:43 +0200 |
| commit | 2f36db71009304b3f0b95afacd8eba1f9f046b87 (patch) | |
| tree | 0ce45950e4043208a1d035effd5a9305d18fe405 /fs/ecryptfs/kthread.c | |
| parent | proc: prevent stacking filesystems on top (diff) | |
| download | linux-2f36db71009304b3f0b95afacd8eba1f9f046b87.tar.xz linux-2f36db71009304b3f0b95afacd8eba1f9f046b87.zip | |
ecryptfs: forbid opening files without mmap handler
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>
Diffstat (limited to 'fs/ecryptfs/kthread.c')
| -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; } |