From c3bf6f9596ea4cea0b5f52a3ac0001ddf2f5dc89 Mon Sep 17 00:00:00 2001 From: riastradh Date: Mon, 27 Jun 2022 04:06:48 +0000 Subject: [PATCH] sendmsg(2): Avoid buffer overrun in ktrace of invalid cmsghdr. Reported-by: syzbot+efded148140b23425f5c@syzkaller.appspotmail.com --- sys/kern/uipc_syscalls.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c index 97059438231aa..6cacd8016178d 100644 --- a/sys/kern/uipc_syscalls.c +++ b/sys/kern/uipc_syscalls.c @@ -1,4 +1,4 @@ -/* $NetBSD: uipc_syscalls.c,v 1.202 2021/10/02 17:37:21 thorpej Exp $ */ +/* $NetBSD: uipc_syscalls.c,v 1.203 2022/06/27 04:06:48 riastradh Exp $ */ /*- * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc. @@ -61,7 +61,7 @@ */ #include -__KERNEL_RCSID(0, "$NetBSD: uipc_syscalls.c,v 1.202 2021/10/02 17:37:21 thorpej Exp $"); +__KERNEL_RCSID(0, "$NetBSD: uipc_syscalls.c,v 1.203 2022/06/27 04:06:48 riastradh Exp $"); #ifdef _KERNEL_OPT #include "opt_pipe.h" @@ -1627,6 +1627,10 @@ sockargs(struct mbuf **mp, const void *bf, size_t buflen, enum uio_seg seg, mhdr.msg_controllen = buflen; for (struct cmsghdr *cmsg = CMSG_FIRSTHDR(&mhdr); cmsg; cmsg = CMSG_NXTHDR(&mhdr, cmsg)) { + KASSERT(((char *)cmsg - mtod(m, char *)) <= buflen); + if (cmsg->cmsg_len > + buflen - ((char *)cmsg - mtod(m, char *))) + break; ktrkuser(mbuftypes[type], cmsg, cmsg->cmsg_len); } return 0;