net: ipmr/ip6mr: fix potential out-of-bounds vif_table access

mfc_parent of cache entries is used to index into the vif_table and is
initialised from mfcctl->mfcc_parent. This can take values of to 2^16-1,
while the vif_table has only MAXVIFS (32) entries. The same problem
affects ip6mr.

Refuse invalid values to fix a potential out-of-bounds access. Unlike
the other validity checks, this is checked in ipmr_mfc_add() instead of
the setsockopt handler since its unused in the delete path and might be
uninitialized.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy 2010-03-17 06:04:14 +00:00 committed by David S. Miller
parent ea93fd9456
commit a50436f2cd
2 changed files with 6 additions and 0 deletions

View File

@ -802,6 +802,9 @@ static int ipmr_mfc_add(struct net *net, struct mfcctl *mfc, int mrtsock)
int line;
struct mfc_cache *uc, *c, **cp;
if (mfc->mfcc_parent >= MAXVIFS)
return -ENFILE;
line = MFC_HASH(mfc->mfcc_mcastgrp.s_addr, mfc->mfcc_origin.s_addr);
for (cp = &net->ipv4.mfc_cache_array[line];

View File

@ -1113,6 +1113,9 @@ static int ip6mr_mfc_add(struct net *net, struct mf6cctl *mfc, int mrtsock)
unsigned char ttls[MAXMIFS];
int i;
if (mfc->mf6cc_parent >= MAXMIFS)
return -ENFILE;
memset(ttls, 255, MAXMIFS);
for (i = 0; i < MAXMIFS; i++) {
if (IF_ISSET(i, &mfc->mf6cc_ifset))