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authorAlexander Potapenko <glider@google.com>2022-11-04 13:32:16 +0300
committerDavid S. Miller <davem@davemloft.net>2022-11-07 15:26:15 +0300
commitc23fb2c82267638f9d206cb96bb93e1f93ad7828 (patch)
tree05cae64d7c51e99706c929554d610716350297d7 /net/ipv6
parent0c175da7b0378445f5ef53904247cfbfb87e0b78 (diff)
downloadlinux-c23fb2c82267638f9d206cb96bb93e1f93ad7828.tar.xz
ipv6: addrlabel: fix infoleak when sending struct ifaddrlblmsg to network
When copying a `struct ifaddrlblmsg` to the network, __ifal_reserved remained uninitialized, resulting in a 1-byte infoleak: BUG: KMSAN: kernel-network-infoleak in __netdev_start_xmit ./include/linux/netdevice.h:4841 __netdev_start_xmit ./include/linux/netdevice.h:4841 netdev_start_xmit ./include/linux/netdevice.h:4857 xmit_one net/core/dev.c:3590 dev_hard_start_xmit+0x1dc/0x800 net/core/dev.c:3606 __dev_queue_xmit+0x17e8/0x4350 net/core/dev.c:4256 dev_queue_xmit ./include/linux/netdevice.h:3009 __netlink_deliver_tap_skb net/netlink/af_netlink.c:307 __netlink_deliver_tap+0x728/0xad0 net/netlink/af_netlink.c:325 netlink_deliver_tap net/netlink/af_netlink.c:338 __netlink_sendskb net/netlink/af_netlink.c:1263 netlink_sendskb+0x1d9/0x200 net/netlink/af_netlink.c:1272 netlink_unicast+0x56d/0xf50 net/netlink/af_netlink.c:1360 nlmsg_unicast ./include/net/netlink.h:1061 rtnl_unicast+0x5a/0x80 net/core/rtnetlink.c:758 ip6addrlbl_get+0xfad/0x10f0 net/ipv6/addrlabel.c:628 rtnetlink_rcv_msg+0xb33/0x1570 net/core/rtnetlink.c:6082 ... Uninit was created at: slab_post_alloc_hook+0x118/0xb00 mm/slab.h:742 slab_alloc_node mm/slub.c:3398 __kmem_cache_alloc_node+0x4f2/0x930 mm/slub.c:3437 __do_kmalloc_node mm/slab_common.c:954 __kmalloc_node_track_caller+0x117/0x3d0 mm/slab_common.c:975 kmalloc_reserve net/core/skbuff.c:437 __alloc_skb+0x27a/0xab0 net/core/skbuff.c:509 alloc_skb ./include/linux/skbuff.h:1267 nlmsg_new ./include/net/netlink.h:964 ip6addrlbl_get+0x490/0x10f0 net/ipv6/addrlabel.c:608 rtnetlink_rcv_msg+0xb33/0x1570 net/core/rtnetlink.c:6082 netlink_rcv_skb+0x299/0x550 net/netlink/af_netlink.c:2540 rtnetlink_rcv+0x26/0x30 net/core/rtnetlink.c:6109 netlink_unicast_kernel net/netlink/af_netlink.c:1319 netlink_unicast+0x9ab/0xf50 net/netlink/af_netlink.c:1345 netlink_sendmsg+0xebc/0x10f0 net/netlink/af_netlink.c:1921 ... This patch ensures that the reserved field is always initialized. Reported-by: syzbot+3553517af6020c4f2813f1003fe76ef3cbffe98d@syzkaller.appspotmail.com Fixes: 2a8cc6c89039 ("[IPV6] ADDRCONF: Support RFC3484 configurable address selection policy table.") Signed-off-by: Alexander Potapenko <glider@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/addrlabel.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index 8a22486cf270..17ac45aa7194 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -437,6 +437,7 @@ static void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
{
struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
ifal->ifal_family = AF_INET6;
+ ifal->__ifal_reserved = 0;
ifal->ifal_prefixlen = prefixlen;
ifal->ifal_flags = 0;
ifal->ifal_index = ifindex;