From 09a910bffea30e087b8ad5d9e22f714feea85920 Mon Sep 17 00:00:00 2001 From: Dave Weinstein Date: Thu, 28 Jul 2016 11:55:41 -0700 Subject: [PATCH] arm: oabi compat: add missing access checks commit 7de249964f5578e67b99699c5f0b405738d820a2 upstream. Add access checks to sys_oabi_epoll_wait() and sys_oabi_semtimedop(). This fixes CVE-2016-3857, a local privilege escalation under CONFIG_OABI_COMPAT. Change-Id: I4aba3b6ac588f55547006a200700b23f6b8d5491 Cc: stable@vger.kernel.org Reported-by: Chiachih Wu Reviewed-by: Kees Cook Reviewed-by: Nicolas Pitre Signed-off-by: Dave Weinstein Signed-off-by: Linus Torvalds Signed-off-by: Willy Tarreau --- arch/arm/kernel/sys_oabi-compat.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/sys_oabi-compat.c b/arch/arm/kernel/sys_oabi-compat.c index 20a6f3a7376f..87c010557b1d 100644 --- a/arch/arm/kernel/sys_oabi-compat.c +++ b/arch/arm/kernel/sys_oabi-compat.c @@ -276,8 +276,12 @@ asmlinkage long sys_oabi_epoll_wait(int epfd, mm_segment_t fs; long ret, err, i; - if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event))) + if (maxevents <= 0 || + maxevents > (INT_MAX/sizeof(*kbuf)) || + maxevents > (INT_MAX/sizeof(*events))) return -EINVAL; + if (!access_ok(VERIFY_WRITE, events, sizeof(*events) * maxevents)) + return -EFAULT; kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL); if (!kbuf) return -ENOMEM; @@ -314,6 +318,8 @@ asmlinkage long sys_oabi_semtimedop(int semid, if (nsops < 1 || nsops > SEMOPM) return -EINVAL; + if (!access_ok(VERIFY_READ, tsops, sizeof(*tsops) * nsops)) + return -EFAULT; sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL); if (!sops) return -ENOMEM;