4.18-stable review patch. If anyone has any objections, please let me know.
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From: Daniel Borkmann daniel@iogearbox.net
[ Upstream commit 037b0b86ecf5646f8eae777d8b52ff8b401692ec ]
Lets not turn the TCP ULP lookup into an arbitrary module loader as we only intend to load ULP modules through this mechanism, not other unrelated kernel modules:
[root@bar]# cat foo.c #include <sys/types.h> #include <sys/socket.h> #include <linux/tcp.h> #include <linux/in.h>
int main(void) { int sock = socket(PF_INET, SOCK_STREAM, 0); setsockopt(sock, IPPROTO_TCP, TCP_ULP, "sctp", sizeof("sctp")); return 0; }
[root@bar]# gcc foo.c -O2 -Wall [root@bar]# lsmod | grep sctp [root@bar]# ./a.out [root@bar]# lsmod | grep sctp sctp 1077248 4 libcrc32c 16384 3 nf_conntrack,nf_nat,sctp [root@bar]#
Fix it by adding module alias to TCP ULP modules, so probing module via request_module() will be limited to tcp-ulp-[name]. The existing modules like kTLS will load fine given tcp-ulp-tls alias, but others will fail to load:
[root@bar]# lsmod | grep sctp [root@bar]# ./a.out [root@bar]# lsmod | grep sctp [root@bar]#
Sockmap is not affected from this since it's either built-in or not.
Fixes: 734942cc4ea6 ("tcp: ULP infrastructure") Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: John Fastabend john.fastabend@gmail.com Acked-by: Song Liu songliubraving@fb.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/tcp.h | 4 ++++ net/ipv4/tcp_ulp.c | 2 +- net/tls/tls_main.c | 1 + 3 files changed, 6 insertions(+), 1 deletion(-)
--- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2023,6 +2023,10 @@ int tcp_set_ulp_id(struct sock *sk, cons void tcp_get_available_ulp(char *buf, size_t len); void tcp_cleanup_ulp(struct sock *sk);
+#define MODULE_ALIAS_TCP_ULP(name) \ + __MODULE_INFO(alias, alias_userspace, name); \ + __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) + /* Call BPF_SOCK_OPS program that returns an int. If the return value * is < 0, then the BPF op failed (for example if the loaded BPF * program does not support the chosen operation or there is no BPF --- a/net/ipv4/tcp_ulp.c +++ b/net/ipv4/tcp_ulp.c @@ -51,7 +51,7 @@ static const struct tcp_ulp_ops *__tcp_u #ifdef CONFIG_MODULES if (!ulp && capable(CAP_NET_ADMIN)) { rcu_read_unlock(); - request_module("%s", name); + request_module("tcp-ulp-%s", name); rcu_read_lock(); ulp = tcp_ulp_find(name); } --- a/net/tls/tls_main.c +++ b/net/tls/tls_main.c @@ -45,6 +45,7 @@ MODULE_AUTHOR("Mellanox Technologies"); MODULE_DESCRIPTION("Transport Layer Security Support"); MODULE_LICENSE("Dual BSD/GPL"); +MODULE_ALIAS_TCP_ULP("tls");
enum { TLSV4,