On Thu, Aug 17, 2023 at 05:13:28PM +0300, Konstantin Meskhidze (A) wrote: > > > 8/17/2023 4:00 PM, Mickaël Salaün пишет: > > Check af_family consistency while handling AF_UNSPEC specifically. > > > > This patch should be squashed into the "Network support for Landlock" > > v11 patch series. > > Thank you so much. > Can I find this patch in > https://git.kernel.org/pub/scm/linux/kernel/git/mic/linux ??? It is now in the landlock-net-v11 branch. > > > > Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx> > > --- > > security/landlock/net.c | 29 ++++- > > tools/testing/selftests/landlock/net_test.c | 124 +++++++++++++------- > > 2 files changed, 108 insertions(+), 45 deletions(-) > > > > diff --git a/security/landlock/net.c b/security/landlock/net.c > > index f8d2be53ac0d..ea5373f774f9 100644 > > --- a/security/landlock/net.c > > +++ b/security/landlock/net.c > > @@ -80,11 +80,11 @@ static int check_socket_access(struct socket *const sock, > > if (WARN_ON_ONCE(domain->num_layers < 1)) > > return -EACCES; > > - /* Checks if it's a TCP socket. */ > > + /* Checks if it's a (potential) TCP socket. */ > > if (sock->type != SOCK_STREAM) > > return 0; > > - /* Checks for minimal header length. */ > > + /* Checks for minimal header length to safely read sa_family. */ > > if (addrlen < offsetofend(struct sockaddr, sa_family)) > > return -EINVAL; > > @@ -106,7 +106,6 @@ static int check_socket_access(struct socket *const sock, > > return 0; > > } > > - /* Specific AF_UNSPEC handling. */ > > if (address->sa_family == AF_UNSPEC) { > > /* > > * Connecting to an address with AF_UNSPEC dissolves the TCP > > @@ -114,6 +113,10 @@ static int check_socket_access(struct socket *const sock, > > * connection while retaining the socket object (i.e., the file > > * descriptor). As for dropping privileges, closing > > * connections is always allowed. > > + * > > + * For a TCP access control system, this request is legitimate. > > + * Let the network stack handle potential inconsistencies and > > + * return -EINVAL if needed. > > */ > > if (access_request == LANDLOCK_ACCESS_NET_CONNECT_TCP) > > return 0; > > @@ -124,14 +127,34 @@ static int check_socket_access(struct socket *const sock, > > * INADDR_ANY (cf. __inet_bind). Checking the address is > > * required to not wrongfully return -EACCES instead of > > * -EAFNOSUPPORT. > > + * > > + * We could return 0 and let the network stack handle these > > + * checks, but it is safer to return a proper error and test > > + * consistency thanks to kselftest. > > */ > > if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP) { > > + /* addrlen has already been checked for AF_UNSPEC. */ > > const struct sockaddr_in *const sockaddr = > > (struct sockaddr_in *)address; > > + if (sock->sk->__sk_common.skc_family != AF_INET) > > + return -EINVAL; > > + > > if (sockaddr->sin_addr.s_addr != htonl(INADDR_ANY)) > > return -EAFNOSUPPORT; > > } > > + } else { > > + /* > > + * Checks sa_family consistency to not wrongfully return > > + * -EACCES instead of -EINVAL. Valid sa_family changes are > > + * only (from AF_INET or AF_INET6) to AF_UNSPEC. > > + * > > + * We could return 0 and let the network stack handle this > > + * check, but it is safer to return a proper error and test > > + * consistency thanks to kselftest. > > + */ > > + if (address->sa_family != sock->sk->__sk_common.skc_family) > > + return -EINVAL; > > } > > id.key.data = (__force uintptr_t)port; > > diff --git a/tools/testing/selftests/landlock/net_test.c b/tools/testing/selftests/landlock/net_test.c > > index 12dc127ea7d1..504a26c63fd9 100644 > > --- a/tools/testing/selftests/landlock/net_test.c > > +++ b/tools/testing/selftests/landlock/net_test.c > > @@ -233,7 +233,7 @@ static int connect_variant(const int sock_fd, > > FIXTURE(protocol) > > { > > - struct service_fixture srv0, srv1, srv2, unspec_any, unspec_srv0; > > + struct service_fixture srv0, srv1, srv2, unspec_any0, unspec_srv0; > > }; > > FIXTURE_VARIANT(protocol) > > @@ -257,8 +257,8 @@ FIXTURE_SETUP(protocol) > > ASSERT_EQ(0, set_service(&self->unspec_srv0, prot_unspec, 0)); > > - ASSERT_EQ(0, set_service(&self->unspec_any, prot_unspec, 0)); > > - self->unspec_any.ipv4_addr.sin_addr.s_addr = htonl(INADDR_ANY); > > + ASSERT_EQ(0, set_service(&self->unspec_any0, prot_unspec, 0)); > > + self->unspec_any0.ipv4_addr.sin_addr.s_addr = htonl(INADDR_ANY); > > setup_loopback(_metadata); > > }; > > @@ -615,20 +615,18 @@ TEST_F(protocol, connect) > > // Kernel FIXME: tcp_sandbox_with_ipv6_tcp and tcp_sandbox_with_unix_stream > > TEST_F(protocol, bind_unspec) > > { > > + const struct landlock_ruleset_attr ruleset_attr = { > > + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP, > > + }; > > + const struct landlock_net_service_attr tcp_bind = { > > + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, > > + .port = self->srv0.port, > > + }; > > int bind_fd, ret; > > if (variant->sandbox == TCP_SANDBOX) { > > - const struct landlock_ruleset_attr ruleset_attr = { > > - .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP, > > - }; > > - const struct landlock_net_service_attr tcp_bind = { > > - .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, > > - .port = self->srv0.port, > > - }; > > - int ruleset_fd; > > - > > - ruleset_fd = landlock_create_ruleset(&ruleset_attr, > > - sizeof(ruleset_attr), 0); > > + const int ruleset_fd = landlock_create_ruleset( > > + &ruleset_attr, sizeof(ruleset_attr), 0); > > ASSERT_LE(0, ruleset_fd); > > /* Allows bind. */ > > @@ -642,8 +640,8 @@ TEST_F(protocol, bind_unspec) > > bind_fd = socket_variant(&self->srv0); > > ASSERT_LE(0, bind_fd); > > - /* Binds on AF_UNSPEC/INADDR_ANY. */ > > - ret = bind_variant(bind_fd, &self->unspec_any); > > + /* Allowed bind on AF_UNSPEC/INADDR_ANY. */ > > + ret = bind_variant(bind_fd, &self->unspec_any0); > > if (variant->prot.domain == AF_INET) { > > EXPECT_EQ(0, ret) > > { > > @@ -655,6 +653,33 @@ TEST_F(protocol, bind_unspec) > > } > > EXPECT_EQ(0, close(bind_fd)); > > + if (variant->sandbox == TCP_SANDBOX) { > > + const int ruleset_fd = landlock_create_ruleset( > > + &ruleset_attr, sizeof(ruleset_attr), 0); > > + ASSERT_LE(0, ruleset_fd); > > + > > + /* Denies bind. */ > > + enforce_ruleset(_metadata, ruleset_fd); > > + EXPECT_EQ(0, close(ruleset_fd)); > > + } > > + > > + bind_fd = socket_variant(&self->srv0); > > + ASSERT_LE(0, bind_fd); > > + > > + /* Denied bind on AF_UNSPEC/INADDR_ANY. */ > > + ret = bind_variant(bind_fd, &self->unspec_any0); > > + if (variant->prot.domain == AF_INET) { > > + if (is_restricted(&variant->prot, variant->sandbox)) { > > + EXPECT_EQ(-EACCES, ret); > > + } else { > > + EXPECT_EQ(0, ret); > > + } > > + } else { > > + EXPECT_EQ(-EINVAL, ret); > > + } > > + EXPECT_EQ(0, close(bind_fd)); > > + > > + /* Checks bind with AF_UNSPEC and the loopback address. */ > > bind_fd = socket_variant(&self->srv0); > > ASSERT_LE(0, bind_fd); > > ret = bind_variant(bind_fd, &self->unspec_srv0); > > @@ -671,34 +696,16 @@ TEST_F(protocol, bind_unspec) > > TEST_F(protocol, connect_unspec) > > { > > + const struct landlock_ruleset_attr ruleset_attr = { > > + .handled_access_net = LANDLOCK_ACCESS_NET_CONNECT_TCP, > > + }; > > + const struct landlock_net_service_attr tcp_connect = { > > + .allowed_access = LANDLOCK_ACCESS_NET_CONNECT_TCP, > > + .port = self->srv0.port, > > + }; > > int bind_fd, client_fd, status; > > pid_t child; > > - if (variant->sandbox == TCP_SANDBOX) { > > - const struct landlock_ruleset_attr ruleset_attr = { > > - .handled_access_net = LANDLOCK_ACCESS_NET_CONNECT_TCP, > > - }; > > - const struct landlock_net_service_attr tcp_connect = { > > - .allowed_access = LANDLOCK_ACCESS_NET_CONNECT_TCP, > > - .port = self->srv0.port, > > - }; > > - int ruleset_fd; > > - > > - ruleset_fd = landlock_create_ruleset(&ruleset_attr, > > - sizeof(ruleset_attr), 0); > > - ASSERT_LE(0, ruleset_fd); > > - > > - /* Allows connect. */ > > - ASSERT_EQ(0, landlock_add_rule(ruleset_fd, > > - LANDLOCK_RULE_NET_SERVICE, > > - &tcp_connect, 0)); > > - enforce_ruleset(_metadata, ruleset_fd); > > - EXPECT_EQ(0, close(ruleset_fd)); > > - } > > - > > - /* Generic connection tests. */ > > - test_bind_and_connect(_metadata, &self->srv0, false, false); > > - > > /* Specific connection tests. */ > > bind_fd = socket_variant(&self->srv0); > > ASSERT_LE(0, bind_fd); > > @@ -726,8 +733,22 @@ TEST_F(protocol, connect_unspec) > > EXPECT_EQ(0, ret); > > } > > + if (variant->sandbox == TCP_SANDBOX) { > > + const int ruleset_fd = landlock_create_ruleset( > > + &ruleset_attr, sizeof(ruleset_attr), 0); > > + ASSERT_LE(0, ruleset_fd); > > + > > + /* Allows connect. */ > > + ASSERT_EQ(0, > > + landlock_add_rule(ruleset_fd, > > + LANDLOCK_RULE_NET_SERVICE, > > + &tcp_connect, 0)); > > + enforce_ruleset(_metadata, ruleset_fd); > > + EXPECT_EQ(0, close(ruleset_fd)); > > + } > > + > > /* Disconnects already connected socket, or set peer. */ > > - ret = connect_variant(connect_fd, &self->unspec_any); > > + ret = connect_variant(connect_fd, &self->unspec_any0); > > if (self->srv0.protocol.domain == AF_UNIX && > > self->srv0.protocol.type == SOCK_STREAM) { > > EXPECT_EQ(-EINVAL, ret); > > @@ -744,6 +765,25 @@ TEST_F(protocol, connect_unspec) > > EXPECT_EQ(0, ret); > > } > > + if (variant->sandbox == TCP_SANDBOX) { > > + const int ruleset_fd = landlock_create_ruleset( > > + &ruleset_attr, sizeof(ruleset_attr), 0); > > + ASSERT_LE(0, ruleset_fd); > > + > > + /* Denies connect. */ > > + enforce_ruleset(_metadata, ruleset_fd); > > + EXPECT_EQ(0, close(ruleset_fd)); > > + } > > + > > + ret = connect_variant(connect_fd, &self->unspec_any0); > > + if (self->srv0.protocol.domain == AF_UNIX && > > + self->srv0.protocol.type == SOCK_STREAM) { > > + EXPECT_EQ(-EINVAL, ret); > > + } else { > > + /* Always allowed to disconnect. */ > > + EXPECT_EQ(0, ret); > > + } > > + > > EXPECT_EQ(0, close(connect_fd)); > > _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE); > > return;
