From 74d9f1ba37010face4bd1449df4d60dd84450b06 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Mon, 7 Jan 2019 15:33:42 +0100 Subject: [PATCH] udhcpc: when decoding DHCP_SUBNET, ensure it is 4 bytes long function old new delta udhcp_run_script 795 801 +6 Signed-off-by: Denys Vlasenko Upstream-Status: Backport CVE: CVE-2019-5747 Affects < 1.30.0 Signed-off-by: Armin Kuster --- networking/udhcp/common.c | 2 +- networking/udhcp/common.h | 2 +- networking/udhcp/dhcpc.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) Index: busybox-1.29.3/networking/udhcp/common.c =================================================================== --- busybox-1.29.3.orig/networking/udhcp/common.c +++ busybox-1.29.3/networking/udhcp/common.c @@ -300,7 +300,7 @@ uint8_t* FAST_FUNC udhcp_get_option32(st { uint8_t *r = udhcp_get_option(packet, code); if (r) { - if (r[-1] != 4) + if (r[-OPT_DATA + OPT_LEN] != 4) r = NULL; } return r; Index: busybox-1.29.3/networking/udhcp/common.h =================================================================== --- busybox-1.29.3.orig/networking/udhcp/common.h +++ busybox-1.29.3/networking/udhcp/common.h @@ -119,7 +119,7 @@ enum { //#define DHCP_TIME_SERVER 0x04 /* RFC 868 time server (32-bit, 0 = 1.1.1900) */ //#define DHCP_NAME_SERVER 0x05 /* IEN 116 _really_ ancient kind of NS */ //#define DHCP_DNS_SERVER 0x06 -//#define DHCP_LOG_SERVER 0x07 /* port 704 UDP log (not syslog) +//#define DHCP_LOG_SERVER 0x07 /* port 704 UDP log (not syslog) */ //#define DHCP_COOKIE_SERVER 0x08 /* "quote of the day" server */ //#define DHCP_LPR_SERVER 0x09 #define DHCP_HOST_NAME 0x0c /* either client informs server or server gives name to client */ Index: busybox-1.29.3/networking/udhcp/dhcpc.c =================================================================== --- busybox-1.29.3.orig/networking/udhcp/dhcpc.c +++ busybox-1.29.3/networking/udhcp/dhcpc.c @@ -526,7 +526,7 @@ static char **fill_envp(struct dhcp_pack temp = udhcp_get_option(packet, code); *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name); putenv(*curr++); - if (code == DHCP_SUBNET) { + if (code == DHCP_SUBNET && temp[-OPT_DATA + OPT_LEN] == 4) { /* Subnet option: make things like "$ip/$mask" possible */ uint32_t subnet; move_from_unaligned32(subnet, temp);