81 lines
2.9 KiB
Diff
81 lines
2.9 KiB
Diff
|
From 2def2ef2ae5f3990aabdbe8a755911902707d268 Mon Sep 17 00:00:00 2001
|
||
|
|
From: PaX Team <pageexec@freemail.hu>
|
||
|
|
Date: Thu, 30 Jan 2014 16:59:25 -0800
|
||
|
|
Subject: [PATCH] x86, x32: Correct invalid use of user timespec in the kernel
|
||
|
|
|
||
|
|
The x32 case for the recvmsg() timout handling is broken:
|
||
|
|
|
||
|
|
asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg,
|
||
|
|
unsigned int vlen, unsigned int flags,
|
||
|
|
struct compat_timespec __user *timeout)
|
||
|
|
{
|
||
|
|
int datagrams;
|
||
|
|
struct timespec ktspec;
|
||
|
|
|
||
|
|
if (flags & MSG_CMSG_COMPAT)
|
||
|
|
return -EINVAL;
|
||
|
|
|
||
|
|
if (COMPAT_USE_64BIT_TIME)
|
||
|
|
return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
|
||
|
|
flags | MSG_CMSG_COMPAT,
|
||
|
|
(struct timespec *) timeout);
|
||
|
|
...
|
||
|
|
|
||
|
|
The timeout pointer parameter is provided by userland (hence the __user
|
||
|
|
annotation) but for x32 syscalls it's simply cast to a kernel pointer
|
||
|
|
and is passed to __sys_recvmmsg which will eventually directly
|
||
|
|
dereference it for both reading and writing. Other callers to
|
||
|
|
__sys_recvmmsg properly copy from userland to the kernel first.
|
||
|
|
|
||
|
|
The bug was introduced by commit ee4fa23c4bfc ("compat: Use
|
||
|
|
COMPAT_USE_64BIT_TIME in net/compat.c") and should affect all kernels
|
||
|
|
since 3.4 (and perhaps vendor kernels if they backported x32 support
|
||
|
|
along with this code).
|
||
|
|
|
||
|
|
Note that CONFIG_X86_X32_ABI gets enabled at build time and only if
|
||
|
|
CONFIG_X86_X32 is enabled and ld can build x32 executables.
|
||
|
|
|
||
|
|
Other uses of COMPAT_USE_64BIT_TIME seem fine.
|
||
|
|
|
||
|
|
This addresses CVE-2014-0038.
|
||
|
|
|
||
|
|
Signed-off-by: PaX Team <pageexec@freemail.hu>
|
||
|
|
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
|
||
|
|
Cc: <stable@vger.kernel.org> # v3.4+
|
||
|
|
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
|
|
---
|
||
|
|
net/compat.c | 9 ++-------
|
||
|
|
1 file changed, 2 insertions(+), 7 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/net/compat.c b/net/compat.c
|
||
|
|
index dd32e34..f50161f 100644
|
||
|
|
--- a/net/compat.c
|
||
|
|
+++ b/net/compat.c
|
||
|
|
@@ -780,21 +780,16 @@ asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg,
|
||
|
|
if (flags & MSG_CMSG_COMPAT)
|
||
|
|
return -EINVAL;
|
||
|
|
|
||
|
|
- if (COMPAT_USE_64BIT_TIME)
|
||
|
|
- return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
|
||
|
|
- flags | MSG_CMSG_COMPAT,
|
||
|
|
- (struct timespec *) timeout);
|
||
|
|
-
|
||
|
|
if (timeout == NULL)
|
||
|
|
return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
|
||
|
|
flags | MSG_CMSG_COMPAT, NULL);
|
||
|
|
|
||
|
|
- if (get_compat_timespec(&ktspec, timeout))
|
||
|
|
+ if (compat_get_timespec(&ktspec, timeout))
|
||
|
|
return -EFAULT;
|
||
|
|
|
||
|
|
datagrams = __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
|
||
|
|
flags | MSG_CMSG_COMPAT, &ktspec);
|
||
|
|
- if (datagrams > 0 && put_compat_timespec(&ktspec, timeout))
|
||
|
|
+ if (datagrams > 0 && compat_put_timespec(&ktspec, timeout))
|
||
|
|
datagrams = -EFAULT;
|
||
|
|
|
||
|
|
return datagrams;
|
||
|
|
--
|
||
|
|
1.8.5.3
|
||
|
|
|