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PaX Team authored
commit 2def2ef2 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 ee4fa23c ("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> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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