* [PATCH bpf 1/2] bpf: Fix [::] -> [::1] rewrite in sys_sendmsg
2019-01-03 22:43 [PATCH bpf 0/2] bpf: Fix [::] -> [::1] rewrite in sys_sendmsg Andrey Ignatov
@ 2019-01-03 22:43 ` Andrey Ignatov
[not found] ` <B09C58438338E249BE54C5BE772C588EBDD59B@BGSMSX106.gar.corp.intel.com>
2019-01-03 22:43 ` [PATCH bpf 2/2] selftests/bpf: Test [::] -> [::1] rewrite in sys_sendmsg in test_sock_addr Andrey Ignatov
1 sibling, 1 reply; 4+ messages in thread
From: Andrey Ignatov @ 2019-01-03 22:43 UTC (permalink / raw)
To: netdev; +Cc: Andrey Ignatov, ast, daniel, nitin.rawat, kernel-team
sys_sendmsg has supported unspecified destination IPv6 (wildcard) for
unconnected UDP sockets since 876c7f41. When [::] is passed by user as
destination, sys_sendmsg rewrites it with [::1] to be consistent with
BSD (see "BSD'ism" comment in the code).
This didn't work when cgroup-bpf was enabled though since the rewrite
[::] -> [::1] happened before passing control to cgroup-bpf block where
fl6.daddr was updated with passed by user sockaddr_in6.sin6_addr (that
might or might not be changed by BPF program). That way if user passed
[::] as dst IPv6 it was first rewritten with [::1] by original code from
876c7f41, but then rewritten back with [::] by cgroup-bpf block.
It happened even when BPF_CGROUP_UDP6_SENDMSG program was not present
(CONFIG_CGROUP_BPF=y was enough).
The fix is to apply BSD'ism after cgroup-bpf block so that [::] is
replaced with [::1] no matter where it came from: passed by user to
sys_sendmsg or set by BPF_CGROUP_UDP6_SENDMSG program.
Fixes: 1cedee13d25a ("bpf: Hooks for sys_sendmsg")
Reported-by: Nitin Rawat <nitin.rawat@intel.com>
Signed-off-by: Andrey Ignatov <rdna@fb.com>
---
net/ipv6/udp.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 9cbf363172bd..cd563f985e1a 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1390,10 +1390,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
ipc6.opt = opt;
fl6.flowi6_proto = sk->sk_protocol;
- if (!ipv6_addr_any(daddr))
- fl6.daddr = *daddr;
- else
- fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
+ fl6.daddr = *daddr;
if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
fl6.saddr = np->saddr;
fl6.fl6_sport = inet->inet_sport;
@@ -1421,6 +1418,9 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
}
}
+ if (ipv6_addr_any(fl6.daddr))
+ fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
+
final_p = fl6_update_dst(&fl6, opt, &final);
if (final_p)
connected = false;
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH bpf 2/2] selftests/bpf: Test [::] -> [::1] rewrite in sys_sendmsg in test_sock_addr
2019-01-03 22:43 [PATCH bpf 0/2] bpf: Fix [::] -> [::1] rewrite in sys_sendmsg Andrey Ignatov
2019-01-03 22:43 ` [PATCH bpf 1/2] " Andrey Ignatov
@ 2019-01-03 22:43 ` Andrey Ignatov
1 sibling, 0 replies; 4+ messages in thread
From: Andrey Ignatov @ 2019-01-03 22:43 UTC (permalink / raw)
To: netdev; +Cc: Andrey Ignatov, ast, daniel, nitin.rawat, kernel-team
Test that sys_sendmsg BPF hook doesn't break sys_sendmsg behaviour to
rewrite destination IPv6 = [::] with [::1] (BSD'ism).
Two test cases are added:
1) User passes dst IPv6 = [::] and BPF_CGROUP_UDP6_SENDMSG program
doesn't touch it.
2) User passes dst IPv6 != [::], but BPF_CGROUP_UDP6_SENDMSG program
rewrites it with [::].
In both cases [::1] is used by sys_sendmsg code eventually and datagram
is sent successfully for unconnected UDP socket.
Example of relevant output:
Test case: sendmsg6: set dst IP = [::] (BSD'ism) .. [PASS]
Test case: sendmsg6: preserve dst IP = [::] (BSD'ism) .. [PASS]
Signed-off-by: Andrey Ignatov <rdna@fb.com>
---
tools/testing/selftests/bpf/test_sock_addr.c | 53 ++++++++++++++++++--
1 file changed, 50 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_sock_addr.c b/tools/testing/selftests/bpf/test_sock_addr.c
index 73b7493d4120..d94336cbd8bd 100644
--- a/tools/testing/selftests/bpf/test_sock_addr.c
+++ b/tools/testing/selftests/bpf/test_sock_addr.c
@@ -44,6 +44,7 @@
#define SERV6_V4MAPPED_IP "::ffff:192.168.0.4"
#define SRC6_IP "::1"
#define SRC6_REWRITE_IP "::6"
+#define WILDCARD6_IP "::"
#define SERV6_PORT 6060
#define SERV6_REWRITE_PORT 6666
@@ -85,12 +86,14 @@ static int bind4_prog_load(const struct sock_addr_test *test);
static int bind6_prog_load(const struct sock_addr_test *test);
static int connect4_prog_load(const struct sock_addr_test *test);
static int connect6_prog_load(const struct sock_addr_test *test);
+static int sendmsg_allow_prog_load(const struct sock_addr_test *test);
static int sendmsg_deny_prog_load(const struct sock_addr_test *test);
static int sendmsg4_rw_asm_prog_load(const struct sock_addr_test *test);
static int sendmsg4_rw_c_prog_load(const struct sock_addr_test *test);
static int sendmsg6_rw_asm_prog_load(const struct sock_addr_test *test);
static int sendmsg6_rw_c_prog_load(const struct sock_addr_test *test);
static int sendmsg6_rw_v4mapped_prog_load(const struct sock_addr_test *test);
+static int sendmsg6_rw_wildcard_prog_load(const struct sock_addr_test *test);
static struct sock_addr_test tests[] = {
/* bind */
@@ -462,6 +465,34 @@ static struct sock_addr_test tests[] = {
SRC6_REWRITE_IP,
SYSCALL_ENOTSUPP,
},
+ {
+ "sendmsg6: set dst IP = [::] (BSD'ism)",
+ sendmsg6_rw_wildcard_prog_load,
+ BPF_CGROUP_UDP6_SENDMSG,
+ BPF_CGROUP_UDP6_SENDMSG,
+ AF_INET6,
+ SOCK_DGRAM,
+ SERV6_IP,
+ SERV6_PORT,
+ SERV6_REWRITE_IP,
+ SERV6_REWRITE_PORT,
+ SRC6_REWRITE_IP,
+ SUCCESS,
+ },
+ {
+ "sendmsg6: preserve dst IP = [::] (BSD'ism)",
+ sendmsg_allow_prog_load,
+ BPF_CGROUP_UDP6_SENDMSG,
+ BPF_CGROUP_UDP6_SENDMSG,
+ AF_INET6,
+ SOCK_DGRAM,
+ WILDCARD6_IP,
+ SERV6_PORT,
+ SERV6_REWRITE_IP,
+ SERV6_PORT,
+ SRC6_IP,
+ SUCCESS,
+ },
{
"sendmsg6: deny call",
sendmsg_deny_prog_load,
@@ -734,16 +765,27 @@ static int connect6_prog_load(const struct sock_addr_test *test)
return load_path(test, CONNECT6_PROG_PATH);
}
-static int sendmsg_deny_prog_load(const struct sock_addr_test *test)
+static int sendmsg_ret_only_prog_load(const struct sock_addr_test *test,
+ int32_t rc)
{
struct bpf_insn insns[] = {
- /* return 0 */
- BPF_MOV64_IMM(BPF_REG_0, 0),
+ /* return rc */
+ BPF_MOV64_IMM(BPF_REG_0, rc),
BPF_EXIT_INSN(),
};
return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));
}
+static int sendmsg_allow_prog_load(const struct sock_addr_test *test)
+{
+ return sendmsg_ret_only_prog_load(test, /*rc*/ 1);
+}
+
+static int sendmsg_deny_prog_load(const struct sock_addr_test *test)
+{
+ return sendmsg_ret_only_prog_load(test, /*rc*/ 0);
+}
+
static int sendmsg4_rw_asm_prog_load(const struct sock_addr_test *test)
{
struct sockaddr_in dst4_rw_addr;
@@ -864,6 +906,11 @@ static int sendmsg6_rw_v4mapped_prog_load(const struct sock_addr_test *test)
return sendmsg6_rw_dst_asm_prog_load(test, SERV6_V4MAPPED_IP);
}
+static int sendmsg6_rw_wildcard_prog_load(const struct sock_addr_test *test)
+{
+ return sendmsg6_rw_dst_asm_prog_load(test, WILDCARD6_IP);
+}
+
static int sendmsg6_rw_c_prog_load(const struct sock_addr_test *test)
{
return load_path(test, SENDMSG6_PROG_PATH);
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread