fs/select.c: fix information leak to userspace

On some architectures __kernel_suseconds_t is int.  On these archs struct
timeval has padding bytes at the end.  This struct is copied to userspace
with these padding bytes uninitialized.  This leads to leaking of contents
of kernel stack memory.

This bug was added with v2.6.27-rc5-286-gb773ad4.

[akpm@linux-foundation.org: avoid the memset on architectures which don't need it]
Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Vasiliy Kulikov 2011-01-12 17:00:00 -08:00 коммит произвёл Linus Torvalds
Родитель 3d130fd03e
Коммит 65329bf46b
1 изменённых файлов: 2 добавлений и 0 удалений

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@ -306,6 +306,8 @@ static int poll_select_copy_remaining(struct timespec *end_time, void __user *p,
rts.tv_sec = rts.tv_nsec = 0;
if (timeval) {
if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec))
memset(&rtv, 0, sizeof(rtv));
rtv.tv_sec = rts.tv_sec;
rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;