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authorCong Wang <xiyou.wangcong@gmail.com>2020-08-15 16:29:15 -0700
committerDavid S. Miller <davem@davemloft.net>2020-08-16 21:03:19 -0700
commit47733f9daf4fe4f7e0eb9e273f21ad3a19130487 (patch)
tree97b766085a58dd6702ea9d14d827c38f9eaf17b8 /net/tipc
parent8c26544f5ace22ee159113a3300de077f2973519 (diff)
downloadlinux-47733f9daf4fe4f7e0eb9e273f21ad3a19130487.tar.bz2
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>
Diffstat (limited to 'net/tipc')
-rw-r--r--net/tipc/netlink_compat.c12
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);