diff options
| author | PaX Team <pageexec@freemail.hu> | 2014-01-30 16:59:25 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-30 18:44:13 -0800 |
| commit | 2def2ef2ae5f3990aabdbe8a755911902707d268 (patch) | |
| tree | 311170d9f7b737cf8fc220bc85b502753476f6ac | |
| parent | 12f2bbd609006f983c1c99d240cf61e6e829a14c (diff) | |
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>
| -rw-r--r-- | net/compat.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/net/compat.c b/net/compat.c index dd32e34c1e2c..f50161fb812e 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; |