From: PaX Team Date: Fri, 31 Jan 2014 00:59:25 +0000 (-0800) Subject: x86, x32: Correct invalid use of user timespec in the kernel X-Git-Tag: v3.4.79~33 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e0af36cc3d6134b0b40c21b4a79c90bb18e5c5f9;p=platform%2Fkernel%2Flinux-stable.git x86, x32: Correct invalid use of user timespec in the kernel commit 2def2ef2ae5f3990aabdbe8a755911902707d268 upstream. 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 Signed-off-by: H. Peter Anvin Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/compat.c b/net/compat.c index 17f997e..93f5423 100644 --- a/net/compat.c +++ b/net/compat.c @@ -789,21 +789,16 @@ 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;