diff options
| -rw-r--r-- | include/net/tcp.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/bpf.h | 78 | ||||
| -rw-r--r-- | net/core/filter.c | 118 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 3 | ||||
| -rwxr-xr-x | scripts/bpf_doc.py | 4 | ||||
| -rw-r--r-- | tools/include/uapi/linux/bpf.h | 78 |
6 files changed, 281 insertions, 1 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index 1e99f5c61f84..9a1efe23fab7 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -432,6 +432,7 @@ u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, struct tcphdr *th, u32 *cookie); u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, struct tcphdr *th, u32 *cookie); +u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss); u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, const struct tcp_request_sock_ops *af_ops, struct sock *sk, struct tcphdr *th); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index f545e39df72a..e81362891596 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5251,6 +5251,80 @@ union bpf_attr { * Pointer to the underlying dynptr data, NULL if the dynptr is * read-only, if the dynptr is invalid, or if the offset and length * is out of bounds. + * + * s64 bpf_tcp_raw_gen_syncookie_ipv4(struct iphdr *iph, struct tcphdr *th, u32 th_len) + * Description + * Try to issue a SYN cookie for the packet with corresponding + * IPv4/TCP headers, *iph* and *th*, without depending on a + * listening socket. + * + * *iph* points to the IPv4 header. + * + * *th* points to the start of the TCP header, while *th_len* + * contains the length of the TCP header (at least + * **sizeof**\ (**struct tcphdr**)). + * Return + * On success, lower 32 bits hold the generated SYN cookie in + * followed by 16 bits which hold the MSS value for that cookie, + * and the top 16 bits are unused. + * + * On failure, the returned value is one of the following: + * + * **-EINVAL** if *th_len* is invalid. + * + * s64 bpf_tcp_raw_gen_syncookie_ipv6(struct ipv6hdr *iph, struct tcphdr *th, u32 th_len) + * Description + * Try to issue a SYN cookie for the packet with corresponding + * IPv6/TCP headers, *iph* and *th*, without depending on a + * listening socket. + * + * *iph* points to the IPv6 header. + * + * *th* points to the start of the TCP header, while *th_len* + * contains the length of the TCP header (at least + * **sizeof**\ (**struct tcphdr**)). + * Return + * On success, lower 32 bits hold the generated SYN cookie in + * followed by 16 bits which hold the MSS value for that cookie, + * and the top 16 bits are unused. + * + * On failure, the returned value is one of the following: + * + * **-EINVAL** if *th_len* is invalid. + * + * **-EPROTONOSUPPORT** if CONFIG_IPV6 is not builtin. + * + * long bpf_tcp_raw_check_syncookie_ipv4(struct iphdr *iph, struct tcphdr *th) + * Description + * Check whether *iph* and *th* contain a valid SYN cookie ACK + * without depending on a listening socket. + * + * *iph* points to the IPv4 header. + * + * *th* points to the TCP header. + * Return + * 0 if *iph* and *th* are a valid SYN cookie ACK. + * + * On failure, the returned value is one of the following: + * + * **-EACCES** if the SYN cookie is not valid. + * + * long bpf_tcp_raw_check_syncookie_ipv6(struct ipv6hdr *iph, struct tcphdr *th) + * Description + * Check whether *iph* and *th* contain a valid SYN cookie ACK + * without depending on a listening socket. + * + * *iph* points to the IPv6 header. + * + * *th* points to the TCP header. + * Return + * 0 if *iph* and *th* are a valid SYN cookie ACK. + * + * On failure, the returned value is one of the following: + * + * **-EACCES** if the SYN cookie is not valid. + * + * **-EPROTONOSUPPORT** if CONFIG_IPV6 is not builtin. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -5457,6 +5531,10 @@ union bpf_attr { FN(dynptr_read), \ FN(dynptr_write), \ FN(dynptr_data), \ + FN(tcp_raw_gen_syncookie_ipv4), \ + FN(tcp_raw_gen_syncookie_ipv6), \ + FN(tcp_raw_check_syncookie_ipv4), \ + FN(tcp_raw_check_syncookie_ipv6), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/net/core/filter.c b/net/core/filter.c index 5af58eb48587..b62d4126a561 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -7444,6 +7444,114 @@ static const struct bpf_func_proto bpf_skb_set_tstamp_proto = { .arg3_type = ARG_ANYTHING, }; +#ifdef CONFIG_SYN_COOKIES +BPF_CALL_3(bpf_tcp_raw_gen_syncookie_ipv4, struct iphdr *, iph, + struct tcphdr *, th, u32, th_len) +{ + u32 cookie; + u16 mss; + + if (unlikely(th_len < sizeof(*th) || th_len != th->doff * 4)) + return -EINVAL; + + mss = tcp_parse_mss_option(th, 0) ?: TCP_MSS_DEFAULT; + cookie = __cookie_v4_init_sequence(iph, th, &mss); + + return cookie | ((u64)mss << 32); +} + +static const struct bpf_func_proto bpf_tcp_raw_gen_syncookie_ipv4_proto = { + .func = bpf_tcp_raw_gen_syncookie_ipv4, + .gpl_only = true, /* __cookie_v4_init_sequence() is GPL */ + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_FIXED_SIZE_MEM, + .arg1_size = sizeof(struct iphdr), + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, +}; + +BPF_CALL_3(bpf_tcp_raw_gen_syncookie_ipv6, struct ipv6hdr *, iph, + struct tcphdr *, th, u32, th_len) +{ +#if IS_BUILTIN(CONFIG_IPV6) + const u16 mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - + sizeof(struct ipv6hdr); + u32 cookie; + u16 mss; + + if (unlikely(th_len < sizeof(*th) || th_len != th->doff * 4)) + return -EINVAL; + + mss = tcp_parse_mss_option(th, 0) ?: mss_clamp; + cookie = __cookie_v6_init_sequence(iph, th, &mss); + + return cookie | ((u64)mss << 32); +#else + return -EPROTONOSUPPORT; +#endif +} + +static const struct bpf_func_proto bpf_tcp_raw_gen_syncookie_ipv6_proto = { + .func = bpf_tcp_raw_gen_syncookie_ipv6, + .gpl_only = true, /* __cookie_v6_init_sequence() is GPL */ + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_FIXED_SIZE_MEM, + .arg1_size = sizeof(struct ipv6hdr), + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, +}; + +BPF_CALL_2(bpf_tcp_raw_check_syncookie_ipv4, struct iphdr *, iph, + struct tcphdr *, th) +{ + u32 cookie = ntohl(th->ack_seq) - 1; + + if (__cookie_v4_check(iph, th, cookie) > 0) + return 0; + + return -EACCES; +} + +static const struct bpf_func_proto bpf_tcp_raw_check_syncookie_ipv4_proto = { + .func = bpf_tcp_raw_check_syncookie_ipv4, + .gpl_only = true, /* __cookie_v4_check is GPL */ + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_FIXED_SIZE_MEM, + .arg1_size = sizeof(struct iphdr), + .arg2_type = ARG_PTR_TO_FIXED_SIZE_MEM, + .arg2_size = sizeof(struct tcphdr), +}; + +BPF_CALL_2(bpf_tcp_raw_check_syncookie_ipv6, struct ipv6hdr *, iph, + struct tcphdr *, th) +{ +#if IS_BUILTIN(CONFIG_IPV6) + u32 cookie = ntohl(th->ack_seq) - 1; + + if (__cookie_v6_check(iph, th, cookie) > 0) + return 0; + + return -EACCES; +#else + return -EPROTONOSUPPORT; +#endif +} + +static const struct bpf_func_proto bpf_tcp_raw_check_syncookie_ipv6_proto = { + .func = bpf_tcp_raw_check_syncookie_ipv6, + .gpl_only = true, /* __cookie_v6_check is GPL */ + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_FIXED_SIZE_MEM, + .arg1_size = sizeof(struct ipv6hdr), + .arg2_type = ARG_PTR_TO_FIXED_SIZE_MEM, + .arg2_size = sizeof(struct tcphdr), +}; +#endif /* CONFIG_SYN_COOKIES */ + #endif /* CONFIG_INET */ bool bpf_helper_changes_pkt_data(void *func) @@ -7856,6 +7964,16 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_tcp_check_syncookie_proto; case BPF_FUNC_tcp_gen_syncookie: return &bpf_tcp_gen_syncookie_proto; +#ifdef CONFIG_SYN_COOKIES + case BPF_FUNC_tcp_raw_gen_syncookie_ipv4: + return &bpf_tcp_raw_gen_syncookie_ipv4_proto; + case BPF_FUNC_tcp_raw_gen_syncookie_ipv6: + return &bpf_tcp_raw_gen_syncookie_ipv6_proto; + case BPF_FUNC_tcp_raw_check_syncookie_ipv4: + return &bpf_tcp_raw_check_syncookie_ipv4_proto; + case BPF_FUNC_tcp_raw_check_syncookie_ipv6: + return &bpf_tcp_raw_check_syncookie_ipv6_proto; +#endif #endif default: return bpf_sk_base_func_proto(func_id); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 2e2a9ece9af2..6426f6a2e744 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3967,7 +3967,7 @@ static bool smc_parse_options(const struct tcphdr *th, /* Try to parse the MSS option from the TCP header. Return 0 on failure, clamped * value on success. */ -static u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss) +u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss) { const unsigned char *ptr = (const unsigned char *)(th + 1); int length = (th->doff * 4) - sizeof(struct tcphdr); @@ -4006,6 +4006,7 @@ static u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss) } return mss; } +EXPORT_SYMBOL_GPL(tcp_parse_mss_option); /* Look for tcp options. Normally only called on SYN and SYNACK packets. * But, this can also be called on packets in the established flow when diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py index 855b937e7585..a0ec321469bd 100755 --- a/scripts/bpf_doc.py +++ b/scripts/bpf_doc.py @@ -635,6 +635,8 @@ class PrinterHelpers(Printer): 'struct bpf_timer', 'struct mptcp_sock', 'struct bpf_dynptr', + 'struct iphdr', + 'struct ipv6hdr', ] known_types = { '...', @@ -686,6 +688,8 @@ class PrinterHelpers(Printer): 'struct bpf_timer', 'struct mptcp_sock', 'struct bpf_dynptr', + 'struct iphdr', + 'struct ipv6hdr', } mapped_types = { 'u8': '__u8', diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index f545e39df72a..e81362891596 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -5251,6 +5251,80 @@ union bpf_attr { * Pointer to the underlying dynptr data, NULL if the dynptr is * read-only, if the dynptr is invalid, or if the offset and length * is out of bounds. + * + * s64 bpf_tcp_raw_gen_syncookie_ipv4(struct iphdr *iph, struct tcphdr *th, u32 th_len) + * Description + * Try to issue a SYN cookie for the packet with corresponding + * IPv4/TCP headers, *iph* and *th*, without depending on a + * listening socket. + * + * *iph* points to the IPv4 header. + * + * *th* points to the start of the TCP header, while *th_len* + * contains the length of the TCP header (at least + * **sizeof**\ (**struct tcphdr**)). + * Return + * On success, lower 32 bits hold the generated SYN cookie in + * followed by 16 bits which hold the MSS value for that cookie, + * and the top 16 bits are unused. + * + * On failure, the returned value is one of the following: + * + * **-EINVAL** if *th_len* is invalid. + * + * s64 bpf_tcp_raw_gen_syncookie_ipv6(struct ipv6hdr *iph, struct tcphdr *th, u32 th_len) + * Description + * Try to issue a SYN cookie for the packet with corresponding + * IPv6/TCP headers, *iph* and *th*, without depending on a + * listening socket. + * + * *iph* points to the IPv6 header. + * + * *th* points to the start of the TCP header, while *th_len* + * contains the length of the TCP header (at least + * **sizeof**\ (**struct tcphdr**)). + * Return + * On success, lower 32 bits hold the generated SYN cookie in + * followed by 16 bits which hold the MSS value for that cookie, + * and the top 16 bits are unused. + * + * On failure, the returned value is one of the following: + * + * **-EINVAL** if *th_len* is invalid. + * + * **-EPROTONOSUPPORT** if CONFIG_IPV6 is not builtin. + * + * long bpf_tcp_raw_check_syncookie_ipv4(struct iphdr *iph, struct tcphdr *th) + * Description + * Check whether *iph* and *th* contain a valid SYN cookie ACK + * without depending on a listening socket. + * + * *iph* points to the IPv4 header. + * + * *th* points to the TCP header. + * Return + * 0 if *iph* and *th* are a valid SYN cookie ACK. + * + * On failure, the returned value is one of the following: + * + * **-EACCES** if the SYN cookie is not valid. + * + * long bpf_tcp_raw_check_syncookie_ipv6(struct ipv6hdr *iph, struct tcphdr *th) + * Description + * Check whether *iph* and *th* contain a valid SYN cookie ACK + * without depending on a listening socket. + * + * *iph* points to the IPv6 header. + * + * *th* points to the TCP header. + * Return + * 0 if *iph* and *th* are a valid SYN cookie ACK. + * + * On failure, the returned value is one of the following: + * + * **-EACCES** if the SYN cookie is not valid. + * + * **-EPROTONOSUPPORT** if CONFIG_IPV6 is not builtin. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -5457,6 +5531,10 @@ union bpf_attr { FN(dynptr_read), \ FN(dynptr_write), \ FN(dynptr_data), \ + FN(tcp_raw_gen_syncookie_ipv4), \ + FN(tcp_raw_gen_syncookie_ipv6), \ + FN(tcp_raw_check_syncookie_ipv4), \ + FN(tcp_raw_check_syncookie_ipv6), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper |