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