Commit 65329bf4 authored Jan 12, 2011 by Vasiliy Kulikov Committed by Linus Torvalds Jan 13, 2011

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>

parent 3d130fd0

fs/select.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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;

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