tequilaOS/platform_system_core
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

libnetutil: Check dhcp respose packet length

Browse source 
Bug: 67474440
Test: Manual

Change-Id: I84b533f0101a56ec01e64c7591f3c7e82f513b2e
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
This commit is contained in:
tintin 2017-10-13 11:11:48 -07:00 committed by Dmitry Shmidt
parent bfe4b5edb3
commit 61f25d4a36
1 changed files with 14 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

14
libnetutils/packet.c
View file

@ -218,6 +218,20 @@ int receive_packet(int s, struct dhcp_msg *msg)
* to construct the pseudo header used in the checksum calculation.
*/
dhcp_size = ntohs(packet.udp.len) - sizeof(packet.udp);
/*
* check validity of dhcp_size.
* 1) cannot be negative or zero.
* 2) src buffer contains enough bytes to copy
* 3) cannot exceed destination buffer
*/
if ((dhcp_size <= 0) ||
((int)(nread - sizeof(struct iphdr) - sizeof(struct udphdr)) < dhcp_size) ||
((int)sizeof(struct dhcp_msg) < dhcp_size)) {
#if VERBOSE
ALOGD("Malformed Packet");
#endif
return -1;
}
saddr = packet.ip.saddr;
daddr = packet.ip.daddr;
nread = ntohs(packet.ip.tot_len);