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| author | Cong Wang <xiyou.wangcong@gmail.com> | 2020-08-16 01:29:15 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-08-17 06:03:19 +0200 |
| commit | 47733f9daf4fe4f7e0eb9e273f21ad3a19130487 (patch) | |
| tree | 97b766085a58dd6702ea9d14d827c38f9eaf17b8 | |
| parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf (diff) | |
| download | linux-47733f9daf4fe4f7e0eb9e273f21ad3a19130487.tar.xz linux-47733f9daf4fe4f7e0eb9e273f21ad3a19130487.zip | |
tipc: fix uninit skb->data in tipc_nl_compat_dumpit()
__tipc_nl_compat_dumpit() has two callers, and it expects them to
pass a valid nlmsghdr via arg->data. This header is artificial and
crafted just for __tipc_nl_compat_dumpit().
tipc_nl_compat_publ_dump() does so by putting a genlmsghdr as well
as some nested attribute, TIPC_NLA_SOCK. But the other caller
tipc_nl_compat_dumpit() does not, this leaves arg->data uninitialized
on this call path.
Fix this by just adding a similar nlmsghdr without any payload in
tipc_nl_compat_dumpit().
This bug exists since day 1, but the recent commit 6ea67769ff33
("net: tipc: prepare attrs in __tipc_nl_compat_dumpit()") makes it
easier to appear.
Reported-and-tested-by: syzbot+0e7181deafa7e0b79923@syzkaller.appspotmail.com
Fixes: d0796d1ef63d ("tipc: convert legacy nl bearer dump to nl compat")
Cc: Jon Maloy <jmaloy@redhat.com>
Cc: Ying Xue <ying.xue@windriver.com>
Cc: Richard Alpe <richard.alpe@ericsson.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/tipc/netlink_compat.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c index 217516357ef2..90e3c70a91ad 100644 --- a/net/tipc/netlink_compat.c +++ b/net/tipc/netlink_compat.c @@ -275,8 +275,9 @@ err_out: static int tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd, struct tipc_nl_compat_msg *msg) { - int err; + struct nlmsghdr *nlh; struct sk_buff *arg; + int err; if (msg->req_type && (!msg->req_size || !TLV_CHECK_TYPE(msg->req, msg->req_type))) @@ -305,6 +306,15 @@ static int tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd, return -ENOMEM; } + nlh = nlmsg_put(arg, 0, 0, tipc_genl_family.id, 0, NLM_F_MULTI); + if (!nlh) { + kfree_skb(arg); + kfree_skb(msg->rep); + msg->rep = NULL; + return -EMSGSIZE; + } + nlmsg_end(arg, nlh); + err = __tipc_nl_compat_dumpit(cmd, msg, arg); if (err) { kfree_skb(msg->rep); |