From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Amanieu dAntras , Oleg Nesterov , Ingo Molnar , Andrew Morton , Linus Torvalds Subject: [PATCH 3.14 30/44] signalfd: fix information leak in signalfd_copyinfo Date: Fri, 14 Aug 2015 10:45:07 -0700 Message-Id: <20150814174402.548083891@linuxfoundation.org> In-Reply-To: <20150814174401.628233291@linuxfoundation.org> References: <20150814174401.628233291@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Amanieu d'Antras commit 3ead7c52bdb0ab44f4bb1feed505a8323cc12ba7 upstream. This function may copy the si_addr_lsb field to user mode when it hasn'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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/signalfd.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/signalfd.c +++ b/fs/signalfd.c @@ -121,8 +121,9 @@ static int signalfd_copyinfo(struct sign * Other callers might not initialize the si_lsb field, * so check explicitly for the right codes here. */ - if (kinfo->si_code == BUS_MCEERR_AR || - kinfo->si_code == BUS_MCEERR_AO) + if (kinfo->si_signo == SIGBUS && + (kinfo->si_code == BUS_MCEERR_AR || + kinfo->si_code == BUS_MCEERR_AO)) err |= __put_user((short) kinfo->si_addr_lsb, &uinfo->ssi_addr_lsb); #endif