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authorMartin KaFai Lau <martin.lau@kernel.org>2022-09-01 17:29:18 -0700
committerAlexei Starovoitov <ast@kernel.org>2022-09-02 20:34:32 -0700
commit273b7f0fb44847c41814a59901977be284daa447 (patch)
tree5df174c0d3aa19ded01d74a70d305574e6237c80 /net/core
parent65ddc82d3b96be5555a36de4e2b4547433a00532 (diff)
downloadlinux-273b7f0fb44847c41814a59901977be284daa447.tar.bz2
bpf: Change bpf_getsockopt(SOL_TCP) to reuse do_tcp_getsockopt()
This patch changes bpf_getsockopt(SOL_TCP) to reuse do_tcp_getsockopt(). It removes the duplicated code from bpf_getsockopt(SOL_TCP). Before this patch, there were some optnames available to bpf_setsockopt(SOL_TCP) but missing in bpf_getsockopt(SOL_TCP). For example, TCP_NODELAY, TCP_MAXSEG, TCP_KEEPIDLE, TCP_KEEPINTVL, and a few more. It surprises users from time to time. This patch automatically closes this gap without duplicating more code. bpf_getsockopt(TCP_SAVED_SYN) does not free the saved_syn, so it stays in sol_tcp_sockopt(). For string name value like TCP_CONGESTION, bpf expects it is always null terminated, so sol_tcp_sockopt() decrements optlen by one before calling do_tcp_getsockopt() and the 'if (optlen < saved_optlen) memset(..,0,..);' in __bpf_getsockopt() will always do a null termination. Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20220902002918.2894511-1-kafai@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/filter.c74
1 files changed, 43 insertions, 31 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 9b26653a7e1f..beadd5b83e6c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5100,8 +5100,9 @@ static int bpf_sol_tcp_setsockopt(struct sock *sk, int optname,
return 0;
}
-static int sol_tcp_setsockopt(struct sock *sk, int optname,
- char *optval, int optlen)
+static int sol_tcp_sockopt(struct sock *sk, int optname,
+ char *optval, int *optlen,
+ bool getopt)
{
if (sk->sk_prot->setsockopt != tcp_setsockopt)
return -EINVAL;
@@ -5118,17 +5119,51 @@ static int sol_tcp_setsockopt(struct sock *sk, int optname,
case TCP_USER_TIMEOUT:
case TCP_NOTSENT_LOWAT:
case TCP_SAVE_SYN:
- if (optlen != sizeof(int))
+ if (*optlen != sizeof(int))
return -EINVAL;
break;
case TCP_CONGESTION:
+ if (*optlen < 2)
+ return -EINVAL;
+ break;
+ case TCP_SAVED_SYN:
+ if (*optlen < 1)
+ return -EINVAL;
break;
default:
- return bpf_sol_tcp_setsockopt(sk, optname, optval, optlen);
+ if (getopt)
+ return -EINVAL;
+ return bpf_sol_tcp_setsockopt(sk, optname, optval, *optlen);
+ }
+
+ if (getopt) {
+ if (optname == TCP_SAVED_SYN) {
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if (!tp->saved_syn ||
+ *optlen > tcp_saved_syn_len(tp->saved_syn))
+ return -EINVAL;
+ memcpy(optval, tp->saved_syn->data, *optlen);
+ /* It cannot free tp->saved_syn here because it
+ * does not know if the user space still needs it.
+ */
+ return 0;
+ }
+
+ if (optname == TCP_CONGESTION) {
+ if (!inet_csk(sk)->icsk_ca_ops)
+ return -EINVAL;
+ /* BPF expects NULL-terminated tcp-cc string */
+ optval[--(*optlen)] = '\0';
+ }
+
+ return do_tcp_getsockopt(sk, SOL_TCP, optname,
+ KERNEL_SOCKPTR(optval),
+ KERNEL_SOCKPTR(optlen));
}
return do_tcp_setsockopt(sk, SOL_TCP, optname,
- KERNEL_SOCKPTR(optval), optlen);
+ KERNEL_SOCKPTR(optval), *optlen);
}
static int sol_ip_setsockopt(struct sock *sk, int optname,
@@ -5183,7 +5218,7 @@ static int __bpf_setsockopt(struct sock *sk, int level, int optname,
else if (IS_ENABLED(CONFIG_IPV6) && level == SOL_IPV6)
return sol_ipv6_setsockopt(sk, optname, optval, optlen);
else if (IS_ENABLED(CONFIG_INET) && level == SOL_TCP)
- return sol_tcp_setsockopt(sk, optname, optval, optlen);
+ return sol_tcp_sockopt(sk, optname, optval, &optlen, false);
return -EINVAL;
}
@@ -5206,31 +5241,8 @@ static int __bpf_getsockopt(struct sock *sk, int level, int optname,
if (level == SOL_SOCKET) {
err = sol_socket_sockopt(sk, optname, optval, &optlen, true);
- } else if (IS_ENABLED(CONFIG_INET) &&
- level == SOL_TCP && sk->sk_prot->getsockopt == tcp_getsockopt) {
- struct inet_connection_sock *icsk;
- struct tcp_sock *tp;
-
- switch (optname) {
- case TCP_CONGESTION:
- icsk = inet_csk(sk);
-
- if (!icsk->icsk_ca_ops || optlen <= 1)
- goto err_clear;
- strncpy(optval, icsk->icsk_ca_ops->name, optlen);
- optval[optlen - 1] = 0;
- break;
- case TCP_SAVED_SYN:
- tp = tcp_sk(sk);
-
- if (optlen <= 0 || !tp->saved_syn ||
- optlen > tcp_saved_syn_len(tp->saved_syn))
- goto err_clear;
- memcpy(optval, tp->saved_syn->data, optlen);
- break;
- default:
- goto err_clear;
- }
+ } else if (IS_ENABLED(CONFIG_INET) && level == SOL_TCP) {
+ err = sol_tcp_sockopt(sk, optname, optval, &optlen, true);
} else if (IS_ENABLED(CONFIG_INET) && level == SOL_IP) {
struct inet_sock *inet = inet_sk(sk);