From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20130411202556.405566685@goodmis.org> Date: Thu, 11 Apr 2013 16:26:05 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: CQ Tang , Mike Marciniszyn , "H. Peter Anvin" Subject: [ 062/171 ] x86-64: Fix the failure case in copy_user_handle_tail() References: <20130411202503.783159048@goodmis.org> Content-Disposition: inline; filename=0062-x86-64-Fix-the-failure-case-in-copy_user_handle_tail.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6.11.2 stable review patch. If anyone has any objections, please let me know. ------------------ From: CQ Tang [ Upstream commit 66db3feb486c01349f767b98ebb10b0c3d2d021b ] The increment of "to" in copy_user_handle_tail() will have incremented before a failure has been noted. This causes us to skip a byte in the failure case. Only do the increment when assured there is no failure. Signed-off-by: CQ Tang Link: http://lkml.kernel.org/r/20130318150221.8439.993.stgit@phlsvslse11.ph.intel.com Signed-off-by: Mike Marciniszyn Signed-off-by: H. Peter Anvin Cc: Signed-off-by: Steven Rostedt --- arch/x86/lib/usercopy_64.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c index e5b130b..cc9de31 100644 --- a/arch/x86/lib/usercopy_64.c +++ b/arch/x86/lib/usercopy_64.c @@ -72,10 +72,10 @@ copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest) char c; unsigned zero_len; - for (; len; --len) { + for (; len; --len, to++) { if (__get_user_nocheck(c, from++, sizeof(char))) break; - if (__put_user_nocheck(c, to++, sizeof(char))) + if (__put_user_nocheck(c, to, sizeof(char))) break; } -- 1.7.10.4