| Message ID | 20180607193443.8131-1-fw@strlen.de |
|---|---|
| State | Accepted |
| Delegated to: | Pablo Neira |
| Headers | show |
| Series | [nf] netfilter: x_tables: initialise match/target check parameter struct | expand |
On Thu, Jun 07, 2018 at 09:34:43PM +0200, Florian Westphal wrote: > syzbot reports following splat: > > BUG: KMSAN: uninit-value in ebt_stp_mt_check+0x24b/0x450 > net/bridge/netfilter/ebt_stp.c:162 > ebt_stp_mt_check+0x24b/0x450 net/bridge/netfilter/ebt_stp.c:162 > xt_check_match+0x1438/0x1650 net/netfilter/x_tables.c:506 > ebt_check_match net/bridge/netfilter/ebtables.c:372 [inline] > ebt_check_entry net/bridge/netfilter/ebtables.c:702 [inline] > > The uninitialised access is > xt_mtchk_param->nft_compat > > ... which should be set to 0. > Fix it by zeroing the struct beforehand, same for tgchk. > > ip(6)tables targetinfo uses c99-style initialiser, so no change > needed there. Applied, thanks Florian. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" 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/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index c2138e7e8263..93600aa606a8 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -709,6 +709,8 @@ ebt_check_entry(struct ebt_entry *e, struct net *net, } i = 0; + memset(&mtpar, 0, sizeof(mtpar)); + memset(&tgpar, 0, sizeof(tgpar)); mtpar.net = tgpar.net = net; mtpar.table = tgpar.table = name; mtpar.entryinfo = tgpar.entryinfo = e; diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 38ab97b0a2ec..ca0dad90803a 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -531,6 +531,7 @@ find_check_entry(struct ipt_entry *e, struct net *net, const char *name, return -ENOMEM; j = 0; + memset(&mtpar, 0, sizeof(mtpar)); mtpar.net = net; mtpar.table = name; mtpar.entryinfo = &e->ip; diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 0758b5bcfb29..7eab959734bc 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -550,6 +550,7 @@ find_check_entry(struct ip6t_entry *e, struct net *net, const char *name, return -ENOMEM; j = 0; + memset(&mtpar, 0, sizeof(mtpar)); mtpar.net = net; mtpar.table = name; mtpar.entryinfo = &e->ipv6;
syzbot reports following splat: BUG: KMSAN: uninit-value in ebt_stp_mt_check+0x24b/0x450 net/bridge/netfilter/ebt_stp.c:162 ebt_stp_mt_check+0x24b/0x450 net/bridge/netfilter/ebt_stp.c:162 xt_check_match+0x1438/0x1650 net/netfilter/x_tables.c:506 ebt_check_match net/bridge/netfilter/ebtables.c:372 [inline] ebt_check_entry net/bridge/netfilter/ebtables.c:702 [inline] The uninitialised access is xt_mtchk_param->nft_compat ... which should be set to 0. Fix it by zeroing the struct beforehand, same for tgchk. ip(6)tables targetinfo uses c99-style initialiser, so no change needed there. Reported-by: syzbot+da4494182233c23a5fcf@syzkaller.appspotmail.com Fixes: 55917a21d0cc0 ("netfilter: x_tables: add context to know if extension runs from nft_compat") Signed-off-by: Florian Westphal <fw@strlen.de> --- net/bridge/netfilter/ebtables.c | 2 ++ net/ipv4/netfilter/ip_tables.c | 1 + net/ipv6/netfilter/ip6_tables.c | 1 + 3 files changed, 4 insertions(+)