[PATCH 3.14 09/29] arm: oabi compat: add missing access checks
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2016-08-14 20:09:10
Also in:
lkml
3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Weinstein <redacted> 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. Reported-by: Chiachih Wu <redacted> Reviewed-by: Kees Cook <redacted> Reviewed-by: Nicolas Pitre <redacted> Signed-off-by: Dave Weinstein <redacted> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/arm/kernel/sys_oabi-compat.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/arch/arm/kernel/sys_oabi-compat.c
+++ b/arch/arm/kernel/sys_oabi-compat.c@@ -275,8 +275,12 @@ asmlinkage long sys_oabi_epoll_wait(int 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;
@@ -313,6 +317,8 @@ asmlinkage long sys_oabi_semtimedop(int 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;