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| author | Vasiliy Kulikov <segooon@gmail.com> | 2011-01-12 17:00:00 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-13 08:03:12 -0800 |
| commit | 65329bf46bf9ddc37845c9a6823a8e8022d305b9 (patch) | |
| tree | 13a3136917e0518493231e9d1d5e05962a715c44 /fs/select.c | |
| parent | 3d130fd03e06672f7700e2cb694b29f9a98227ca (diff) | |
| download | lwn-65329bf46bf9ddc37845c9a6823a8e8022d305b9.tar.gz lwn-65329bf46bf9ddc37845c9a6823a8e8022d305b9.zip | |
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>
Diffstat (limited to 'fs/select.c')
| -rw-r--r-- | fs/select.c | 2 |
1 files changed, 2 insertions, 0 deletions
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; |