diff options
| author | Florian Westphal <fw@strlen.de> | 2020-02-06 00:39:37 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-06 11:25:09 +0100 |
| commit | b0519de8b3f1caf10632aca55def999ec2d2f1bc (patch) | |
| tree | b95ccc010e7691b0715d76e2b9f74e4489876894 /net | |
| parent | 0202d293c2faecba791ba4afc5aec086249c393d (diff) | |
mptcp: fix use-after-free for ipv6
Turns out that when we accept a new subflow, the newly created
inet_sk(tcp_sk)->pinet6 points at the ipv6_pinfo structure of the
listener socket.
This wasn't caught by the selftest because it closes the accepted fd
before the listening one.
adding a close(listenfd) after accept returns is enough:
BUG: KASAN: use-after-free in inet6_getname+0x6ba/0x790
Read of size 1 at addr ffff88810e310866 by task mptcp_connect/2518
Call Trace:
inet6_getname+0x6ba/0x790
__sys_getpeername+0x10b/0x250
__x64_sys_getpeername+0x6f/0xb0
also alter test program to exercise this.
Reported-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/mptcp/protocol.c | 36 |
1 files changed, 33 insertions, 3 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 353f2d16b986..73780b4cb108 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -24,6 +24,13 @@ #define MPTCP_SAME_STATE TCP_MAX_STATES +#if IS_ENABLED(CONFIG_MPTCP_IPV6) +struct mptcp6_sock { + struct mptcp_sock msk; + struct ipv6_pinfo np; +}; +#endif + /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not * completed yet or has failed, return the subflow socket. * Otherwise return NULL. @@ -627,6 +634,30 @@ static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr; } +#if IS_ENABLED(CONFIG_MPTCP_IPV6) +static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk) +{ + unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo); + + return (struct ipv6_pinfo *)(((u8 *)sk) + offset); +} +#endif + +struct sock *mptcp_sk_clone_lock(const struct sock *sk) +{ + struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC); + + if (!nsk) + return NULL; + +#if IS_ENABLED(CONFIG_MPTCP_IPV6) + if (nsk->sk_family == AF_INET6) + inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); +#endif + + return nsk; +} + static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, bool kern) { @@ -657,7 +688,7 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, lock_sock(sk); local_bh_disable(); - new_mptcp_sock = sk_clone_lock(sk, GFP_ATOMIC); + new_mptcp_sock = mptcp_sk_clone_lock(sk); if (!new_mptcp_sock) { *err = -ENOBUFS; local_bh_enable(); @@ -1206,8 +1237,7 @@ int mptcp_proto_v6_init(void) strcpy(mptcp_v6_prot.name, "MPTCPv6"); mptcp_v6_prot.slab = NULL; mptcp_v6_prot.destroy = mptcp_v6_destroy; - mptcp_v6_prot.obj_size = sizeof(struct mptcp_sock) + - sizeof(struct ipv6_pinfo); + mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); err = proto_register(&mptcp_v6_prot, 1); if (err) |