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 --- net/ipv4/ipmr.c | 3 +++ net/ipv6/ip6mr.c | 3 +++ 2 files changed, 6 insertions(+), 0 deletions(-) diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index 8582e12..0b9d03c 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -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]; diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 52e0f74..23e4ac0 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -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)) -- 1.6.5.7