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authorPaX Team <pageexec@freemail.hu>2014-01-30 16:59:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-30 18:44:13 -0800
commit2def2ef2ae5f3990aabdbe8a755911902707d268 (patch)
tree311170d9f7b737cf8fc220bc85b502753476f6ac /net/compat.c
parent12f2bbd609006f983c1c99d240cf61e6e829a14c (diff)
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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>
Diffstat (limited to 'net/compat.c')
-rw-r--r--net/compat.c9
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;