From 4b83a9049a983b20b1ec2757727c5e39f5847ad2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 21 May 2018 16:35:24 -0700 Subject: [PATCH] netfilter: provide correct argument to nla_strlcpy() Recent patch forgot to remove nla_data(), upsetting syzkaller a bit. BUG: KASAN: slab-out-of-bounds in nla_strlcpy+0x13d/0x150 lib/nlattr.c:314 Read of size 1 at addr ffff8801ad1f4fdd by task syz-executor189/4509 CPU: 1 PID: 4509 Comm: syz-executor189 Not tainted 4.17.0-rc6+ #62 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 nla_strlcpy+0x13d/0x150 lib/nlattr.c:314 nfnl_acct_new+0x574/0xc50 net/netfilter/nfnetlink_acct.c:118 nfnetlink_rcv_msg+0xdb5/0xff0 net/netfilter/nfnetlink.c:212 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448 nfnetlink_rcv+0x1fe/0x1ba0 net/netfilter/nfnetlink.c:513 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336 netlink_sendmsg+0x9f0/0xfa0 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 sock_write_iter+0x35a/0x5a0 net/socket.c:908 call_write_iter include/linux/fs.h:1784 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x64d/0x960 fs/read_write.c:487 vfs_write+0x1f8/0x560 fs/read_write.c:549 ksys_write+0xf9/0x250 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 Fixes: 4e09fc873d92 ("netfilter: prefer nla_strlcpy for dealing with NLA_STRING attributes") Signed-off-by: Eric Dumazet Acked-by: Florian Westphal Reported-by: syzbot Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_acct.c | 2 +- net/netfilter/nfnetlink_cthelper.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/net/netfilter/nfnetlink_acct.c b/net/netfilter/nfnetlink_acct.c index 6ddf891..a0e5adf 100644 --- a/net/netfilter/nfnetlink_acct.c +++ b/net/netfilter/nfnetlink_acct.c @@ -115,7 +115,7 @@ static int nfnl_acct_new(struct net *net, struct sock *nfnl, nfacct->flags = flags; } - nla_strlcpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX); + nla_strlcpy(nfacct->name, tb[NFACCT_NAME], NFACCT_NAME_MAX); if (tb[NFACCT_BYTES]) { atomic64_set(&nfacct->bytes, diff --git a/net/netfilter/nfnetlink_cthelper.c b/net/netfilter/nfnetlink_cthelper.c index fa026b2..cb5b5f2 100644 --- a/net/netfilter/nfnetlink_cthelper.c +++ b/net/netfilter/nfnetlink_cthelper.c @@ -150,7 +150,7 @@ nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy, return -EINVAL; nla_strlcpy(expect_policy->name, - nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN); + tb[NFCTH_POLICY_NAME], NF_CT_HELPER_NAME_LEN); expect_policy->max_expected = ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX])); if (expect_policy->max_expected > NF_CT_EXPECT_MAX_CNT) @@ -235,7 +235,7 @@ nfnl_cthelper_create(const struct nlattr * const tb[], goto err1; nla_strlcpy(helper->name, - nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN); + tb[NFCTH_NAME], NF_CT_HELPER_NAME_LEN); size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN])); if (size > FIELD_SIZEOF(struct nf_conn_help, data)) { ret = -ENOMEM; -- 1.9.1