From f2c99d387c4770a7516237d5829b140e41a748d9 Mon Sep 17 00:00:00 2001 From: Brooks Davis Date: Tue, 22 Nov 2016 22:45:15 +0000 Subject: [PATCH] Allocate a struct ifreq rather than using a (wrong) computed size for the BIOCSETIF ioctl. The kernel always copies an entire struct ifreq and IPv4 addresses will always fit in an ifreq. On systems with pointers larger than 64-bits, the computed size will be less than the size of struct ifreq, potentially resulting in the kernel attempting to copyin memory from outside the allocation. Reviewed by: jhb Obtained from: CheriBSD MFC after: 1 week Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D8445 --- sbin/dhclient/dispatch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sbin/dhclient/dispatch.c b/sbin/dhclient/dispatch.c index b4e4f463e973..c1bed523fdc9 100644 --- a/sbin/dhclient/dispatch.c +++ b/sbin/dhclient/dispatch.c @@ -106,8 +106,8 @@ discover_interfaces(struct interface_info *iface) if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK)) continue; if (!iface->ifp) { - int len = IFNAMSIZ + ifa->ifa_addr->sa_len; - if ((tif = malloc(len)) == NULL) + if ((tif = calloc(1, sizeof(struct ifreq))) + == NULL) error("no space to remember ifp"); strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); memcpy(&tif->ifr_addr, ifa->ifa_addr,