[PATCH 5.15 309/917] inet: remove races in inet{6}_getname()

Greg Kroah-Hartman
2021-11-16T00:54:56Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 9dfc685e0262d4c5e44e13302f89841fa75173ca ]

syzbot reported data-races in inet_getname() multiple times,
it is time we fix this instead of pretending applications
should not trigger them.

getsockname() and getpeername() are not really considered fast path.

v2: added the missing BPF_CGROUP_RUN_SA_PROG() declaration
needed when CONFIG_CGROUP_BPF=n, as reported by
kernel test robot <lkp@intel.com>

syzbot typical report:

BUG: KCSAN: data-race in __inet_hash_connect / inet_getname

write to 0xffff888136d66cf8 of 2 bytes by task 14374 on cpu 1:
__inet_hash_connect+0x7ec/0x950 net/ipv4/inet_hashtables.c:831
inet_hash_connect+0x85/0x90 net/ipv4/inet_hashtables.c:853
tcp_v4_connect+0x782/0xbb0 net/ipv4/tcp_ipv4.c:275
__inet_stream_connect+0x156/0x6e0 net/ipv4/af_inet.c:664
inet_stream_connect+0x44/0x70 net/ipv4/af_inet.c:728
__sys_connect_file net/socket.c:1896 [inline]
__sys_connect+0x254/0x290 net/socket.c:1913
__do_sys_connect net/socket.c:1923 [inline]
__se_sys_connect net/socket.c:1920 [inline]
__x64_sys_connect+0x3d/0x50 net/socket.c:1920
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888136d66cf8 of 2 bytes by task 14408 on cpu 0:
inet_getname+0x11f/0x170 net/ipv4/af_inet.c:790
__sys_getsockname+0x11d/0x1b0 net/socket.c:1946
__do_sys_getsockname net/socket.c:1961 [inline]
__se_sys_getsockname net/socket.c:1958 [inline]
__x64_sys_getsockname+0x3e/0x50 net/socket.c:1958
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000 -> 0xdee0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14408 Comm: syz-executor.3 Not tainted 5.15.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20211026213014.3026708-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/bpf-cgroup.h | 1 +
net/ipv4/af_inet.c | 16 +++++++++-------
net/ipv6/af_inet6.c | 21 +++++++++++----------
3 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 2746fd8042162..3536ab432b30c 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -517,6 +517,7 @@ static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map,

#define cgroup_bpf_enabled(atype) (0)
#define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, atype, t_ctx) ({ 0; })
+#define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, atype) ({ 0; })
#define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (0)
#define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; })
#define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk,skb) ({ 0; })
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 1d816a5fd3eb9..64062b7ce61df 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -773,26 +773,28 @@ int inet_getname(struct socket *sock, struct sockaddr *uaddr,
DECLARE_SOCKADDR(struct sockaddr_in *, sin, uaddr);

sin->sin_family = AF_INET;
+ lock_sock(sk);
if (peer) {
if (!inet->inet_dport ||
(((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
- peer == 1))
+ peer == 1)) {
+ release_sock(sk);
return -ENOTCONN;
+ }
sin->sin_port = inet->inet_dport;
sin->sin_addr.s_addr = inet->inet_daddr;
- BPF_CGROUP_RUN_SA_PROG_LOCK(sk, (struct sockaddr *)sin,
- CGROUP_INET4_GETPEERNAME,
- NULL);
+ BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin,
+ CGROUP_INET4_GETPEERNAME);
} else {
__be32 addr = inet->inet_rcv_saddr;
if (!addr)
addr = inet->inet_saddr;
sin->sin_port = inet->inet_sport;
sin->sin_addr.s_addr = addr;
- BPF_CGROUP_RUN_SA_PROG_LOCK(sk, (struct sockaddr *)sin,
- CGROUP_INET4_GETSOCKNAME,
- NULL);
+ BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin,
+ CGROUP_INET4_GETSOCKNAME);
}
+ release_sock(sk);
memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
return sizeof(*sin);
}
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index b5878bb8e419d..0c4da163535ad 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -521,31 +521,32 @@ int inet6_getname(struct socket *sock, struct sockaddr *uaddr,
sin->sin6_family = AF_INET6;
sin->sin6_flowinfo = 0;
sin->sin6_scope_id = 0;
+ lock_sock(sk);
if (peer) {
- if (!inet->inet_dport)
- return -ENOTCONN;
- if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
- peer == 1)
+ if (!inet->inet_dport ||
+ (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
+ peer == 1)) {
+ release_sock(sk);
return -ENOTCONN;
+ }
sin->sin6_port = inet->inet_dport;
sin->sin6_addr = sk->sk_v6_daddr;
if (np->sndflow)
sin->sin6_flowinfo = np->flow_label;
- BPF_CGROUP_RUN_SA_PROG_LOCK(sk, (struct sockaddr *)sin,
- CGROUP_INET6_GETPEERNAME,
- NULL);
+ BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin,
+ CGROUP_INET6_GETPEERNAME);
} else {
if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
sin->sin6_addr = np->saddr;
else
sin->sin6_addr = sk->sk_v6_rcv_saddr;
sin->sin6_port = inet->inet_sport;
- BPF_CGROUP_RUN_SA_PROG_LOCK(sk, (struct sockaddr *)sin,
- CGROUP_INET6_GETSOCKNAME,
- NULL);
+ BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin,
+ CGROUP_INET6_GETSOCKNAME);
}
sin->sin6_scope_id = ipv6_iface_scope_id(&sin->sin6_addr,
sk->sk_bound_dev_if);
+ release_sock(sk);
return sizeof(*sin);
}
EXPORT_SYMBOL(inet6_getname);
--
2.33.0