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authorJann Horn <jannh@google.com>2016-06-01 11:55:06 +0200
committerSasha Levin <sasha.levin@oracle.com>2016-06-19 23:47:47 -0400
commitdd536b607688315b3043ab5fd5243c3f530922a2 (patch)
tree400d582a4499deaac5b06725e292074a01be39ee
parent70e21269e3ec8e4345e7fcd263f9a8f2a43f42df (diff)
ecryptfs: forbid opening files without mmap handler
[ Upstream 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> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--fs/ecryptfs/kthread.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/fs/ecryptfs/kthread.c b/fs/ecryptfs/kthread.c
index f1ea610362c6..9b661a4ccee7 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(lower_dentry->d_inode) ? 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;
}