| Message ID | 20100326.095137.165317348.davem@davemloft.net |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
yes, but I think that it is not enough, ip[6]mr_mfc_add() is only called via setsockopt(). When a multicast packet arrived in ip6_mr_input(), if there is no cache ip6mr_cache_unresolved() will be called and this function will add an entry with parent == 65535. And the second problem is that when a vif is removed, no cleanup is made in cache entry. Hence, we can have a cache entry which points to an invalid vif (dev is set ot NULL). Regards, Nicolas Le 26.03.2010 17:51, David Miller a écrit : > From: Nicolas Dichtel <nicolas.dichtel@dev.6wind.com> > Date: Fri, 26 Mar 2010 10:45:35 +0100 > >> please consider the attached patch about IPv4 and IPv6 multicast. > > Already fixed by Patrick McHardy recently: > > commit a50436f2cd6e85794f7e1aad795ca8302177b896 > Author: Patrick McHardy <kaber@trash.net> > Date: Wed Mar 17 06:04:14 2010 +0000 > > 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> > > 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)) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Nicolas Dichtel <nicolas.dichtel@dev.6wind.com> Date: Fri, 26 Mar 2010 18:19:34 +0100 > yes, but I think that it is not enough, ip[6]mr_mfc_add() is only > called via setsockopt(). > > When a multicast packet arrived in ip6_mr_input(), if there is no > cache ip6mr_cache_unresolved() will be called and this function will > add an entry with parent == 65535. > > And the second problem is that when a vif is removed, no cleanup is > made in cache entry. Hence, we can have a cache entry which points to > an invalid vif (dev is set ot NULL). Ok, I'll take another look at your patch, thanks for explaining. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Nicolas Dichtel <nicolas.dichtel@dev.6wind.com> Date: Fri, 26 Mar 2010 18:19:34 +0100 > When a multicast packet arrived in ip6_mr_input(), if there is no > cache ip6mr_cache_unresolved() will be called and this function will > add an entry with parent == 65535. > > And the second problem is that when a vif is removed, no cleanup is > made in cache entry. Hence, we can have a cache entry which points to > an invalid vif (dev is set ot NULL). I've applied your fix, thanks Nicolas. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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))