60 lines
1.7 KiB
Diff
60 lines
1.7 KiB
Diff
From 2f36db71009304b3f0b95afacd8eba1f9f046b87 Mon Sep 17 00:00:00 2001
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From: Jann Horn <jannh@google.com>
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Date: Wed, 1 Jun 2016 11:55:06 +0200
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Subject: [PATCH] ecryptfs: forbid opening files without mmap handler
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This prevents users from triggering a stack overflow through a recursive
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invocation of pagefault handling that involves mapping procfs files into
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virtual memory.
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Signed-off-by: Jann Horn <jannh@google.com>
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Acked-by: Tyler Hicks <tyhicks@canonical.com>
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Cc: stable@vger.kernel.org
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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fs/ecryptfs/kthread.c | 13 +++++++++++--
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1 file changed, 11 insertions(+), 2 deletions(-)
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diff --git a/fs/ecryptfs/kthread.c b/fs/ecryptfs/kthread.c
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index 866bb18efefe..e818f5ac7a26 100644
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--- a/fs/ecryptfs/kthread.c
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+++ b/fs/ecryptfs/kthread.c
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@@ -25,6 +25,7 @@
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#include <linux/slab.h>
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#include <linux/wait.h>
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#include <linux/mount.h>
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+#include <linux/file.h>
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#include "ecryptfs_kernel.h"
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struct ecryptfs_open_req {
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@@ -147,7 +148,7 @@ int ecryptfs_privileged_open(struct file **lower_file,
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flags |= IS_RDONLY(d_inode(lower_dentry)) ? O_RDONLY : O_RDWR;
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(*lower_file) = dentry_open(&req.path, flags, cred);
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if (!IS_ERR(*lower_file))
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- goto out;
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+ goto have_file;
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if ((flags & O_ACCMODE) == O_RDONLY) {
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rc = PTR_ERR((*lower_file));
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goto out;
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@@ -165,8 +166,16 @@ int ecryptfs_privileged_open(struct file **lower_file,
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mutex_unlock(&ecryptfs_kthread_ctl.mux);
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wake_up(&ecryptfs_kthread_ctl.wait);
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wait_for_completion(&req.done);
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- if (IS_ERR(*lower_file))
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+ if (IS_ERR(*lower_file)) {
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rc = PTR_ERR(*lower_file);
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+ goto out;
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+ }
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+have_file:
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+ if ((*lower_file)->f_op->mmap == NULL) {
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+ fput(*lower_file);
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+ *lower_file = NULL;
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+ rc = -EMEDIUMTYPE;
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+ }
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out:
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return rc;
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}
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--
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2.5.5
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