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udhcpc: when decoding DHCP_SUBNET, ensure it is 4 bytes long

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function                                             old     new   delta
udhcp_run_script                                     795     801      +6

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2019-01-07 15:33:42 +01:00
parent b80bdeba02
commit 74d9f1ba37
3 changed files with 3 additions and 3 deletions
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2
networking/udhcp/common.c
View File

@ -302,7 +302,7 @@ uint8_t* FAST_FUNC udhcp_get_option32(struct dhcp_packet *packet, int code)
{
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;

2
networking/udhcp/common.h
View File

@ -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 /* 12: either client informs server or server gives name to client */

2
networking/udhcp/dhcpc.c
View File

@ -531,7 +531,7 @@ static char **fill_envp(struct dhcp_packet *packet)
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);