kernel/sys.c: fix stack memory content leak via UNAME26
authorKees Cook <keescook@chromium.org>
Fri, 19 Oct 2012 20:56:51 +0000 (13:56 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 28 Oct 2012 17:14:13 +0000 (10:14 -0700)
commit643fde8ed4ea75f5d113803084806eff14d97454
tree89ce9d1661b1bfffb06a26b3b112f1df9d5181ed
parent6eca486b8d28b1fe1d147cf55dfb8832099bb0a2
kernel/sys.c: fix stack memory content leak via UNAME26

commit 2702b1526c7278c4d65d78de209a465d4de2885e upstream.

Calling uname() with the UNAME26 personality set allows a leak of kernel
stack contents.  This fixes it by defensively calculating the length of
copy_to_user() call, making the len argument unsigned, and initializing
the stack buffer to zero (now technically unneeded, but hey, overkill).

CVE-2012-0957

Reported-by: PaX Team <pageexec@freemail.hu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernel/sys.c