From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:48512 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753799AbbH0Psd (ORCPT ); Thu, 27 Aug 2015 11:48:33 -0400 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: "Amanieu d'Antras" , Oleg Nesterov , Ingo Molnar , Russell King , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman , Sasha Levin Subject: [added to the 3.18 stable tree] signal: fix information leak in copy_siginfo_to_user Date: Thu, 27 Aug 2015 11:38:05 -0400 Message-Id: <1440689954-10813-47-git-send-email-sasha.levin@oracle.com> In-Reply-To: <1440689954-10813-1-git-send-email-sasha.levin@oracle.com> References: <1440689954-10813-1-git-send-email-sasha.levin@oracle.com> Sender: stable-owner@vger.kernel.org List-ID: From: Amanieu d'Antras This patch has been added to the 3.18 stable tree. If you have any objections, please let us know. =============== [ Upstream commit c08a75d950725cdd87c19232a5a3850c51520359 ] commit 26135022f85105ad725cda103fa069e29e83bd16 upstream. This function may copy the si_addr_lsb, si_lower and si_upper fields to user mode when they haven't been initialized, which can leak kernel stack data to user mode. Just checking the value of si_code is insufficient because the same si_code value is shared between multiple signals. This is solved by checking the value of si_signo in addition to si_code. Signed-off-by: Amanieu d'Antras Cc: Oleg Nesterov Cc: Ingo Molnar Cc: Russell King Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- arch/arm64/kernel/signal32.c | 3 ++- kernel/signal.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 76920d4..5c96149 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -168,7 +168,8 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from) * Other callers might not initialize the si_lsb field, * so check explicitely for the right codes here. */ - if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) + if (from->si_signo == SIGBUS && + (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)) err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); #endif break; diff --git a/kernel/signal.c b/kernel/signal.c index 8f0876f..dfbb40e 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2745,7 +2745,8 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) * Other callers might not initialize the si_lsb field, * so check explicitly for the right codes here. */ - if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) + if (from->si_signo == SIGBUS && + (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)) err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); #endif break; -- 2.1.4