From: Dave Weinstein Date: Thu, 28 Jul 2016 18:55:41 +0000 (-0700) Subject: arm: oabi compat: add missing access checks X-Git-Tag: Ubuntu-5.2.0-15.16~8616 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=7de249964f5578e67b99699c5f0b405738d820a2;p=mirror_ubuntu-eoan-kernel.git arm: oabi compat: add missing access checks 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. 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 --- diff --git a/arch/arm/kernel/sys_oabi-compat.c b/arch/arm/kernel/sys_oabi-compat.c index 087acb569b63..5f221acd21ae 100644 --- a/arch/arm/kernel/sys_oabi-compat.c +++ b/arch/arm/kernel/sys_oabi-compat.c @@ -279,8 +279,12 @@ 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; @@ -317,6 +321,8 @@ 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;