From 65329bf46bf9ddc37845c9a6823a8e8022d305b9 Mon Sep 17 00:00:00 2001 From: Vasiliy Kulikov Date: Wed, 12 Jan 2011 17:00:00 -0800 Subject: [PATCH] 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 Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/select.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/select.c b/fs/select.c index b7b10aa30861..e56560d2b08a 100644 --- a/fs/select.c +++ b/fs/select.c @@ -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;