From 0608c69c9a805c6264689d7eab4203eab88cf1da Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Thu, 20 Dec 2018 11:35:35 -0800 Subject: [PATCH] bpf: sk_msg, sock{map|hash} redirect through ULP A sockmap program that redirects through a kTLS ULP enabled socket will not work correctly because the ULP layer is skipped. This fixes the behavior to call through the ULP layer on redirect to ensure any operations required on the data stream at the ULP layer continue to be applied. To do this we add an internal flag MSG_SENDPAGE_NOPOLICY to avoid calling the BPF layer on a redirected message. This is required to avoid calling the BPF layer multiple times (possibly recursively) which is not the current/expected behavior without ULPs. In the future we may add a redirect flag if users _do_ want the policy applied again but this would need to work for both ULP and non-ULP sockets and be opt-in to avoid breaking existing programs. Also to avoid polluting the flag space with an internal flag we reuse the flag space overlapping MSG_SENDPAGE_NOPOLICY with MSG_WAITFORONE. Here WAITFORONE is specific to recv path and SENDPAGE_NOPOLICY is only used for sendpage hooks. The last thing to verify is user space API is masked correctly to ensure the flag can not be set by user. (Note this needs to be true regardless because we have internal flags already in-use that user space should not be able to set). But for completeness we have two UAPI paths into sendpage, sendfile and splice. In the sendfile case the function do_sendfile() zero's flags, ./fs/read_write.c: static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, size_t count, loff_t max) { ... fl = 0; #if 0 /* * We need to debate whether we can enable this or not. The * man page documents EAGAIN return for the output at least, * and the application is arguably buggy if it doesn't expect * EAGAIN on a non-blocking file descriptor. */ if (in.file->f_flags & O_NONBLOCK) fl = SPLICE_F_NONBLOCK; #endif file_start_write(out.file); retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl); } In the splice case the pipe_to_sendpage "actor" is used which masks flags with SPLICE_F_MORE. ./fs/splice.c: static int pipe_to_sendpage(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct splice_desc *sd) { ... more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; ... } Confirming what we expect that internal flags are in fact internal to socket side. Fixes: d3b18ad31f93 ("tls: add bpf support to sk_msg handling") Signed-off-by: John Fastabend Signed-off-by: Daniel Borkmann --- include/linux/socket.h | 1 + include/net/tls.h | 9 +++++++++ net/ipv4/tcp_bpf.c | 13 ++++++++++++- net/tls/tls_sw.c | 43 +++++++++++++++++++++++++++++------------- 4 files changed, 52 insertions(+), 14 deletions(-) diff --git a/include/linux/socket.h b/include/linux/socket.h index 8b571e9b9f76..84c48a3c0227 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -286,6 +286,7 @@ struct ucred { #define MSG_NOSIGNAL 0x4000 /* Do not generate SIGPIPE */ #define MSG_MORE 0x8000 /* Sender will send more */ #define MSG_WAITFORONE 0x10000 /* recvmmsg(): block until 1+ packets avail */ +#define MSG_SENDPAGE_NOPOLICY 0x10000 /* sendpage() internal : do no apply policy */ #define MSG_SENDPAGE_NOTLAST 0x20000 /* sendpage() internal : not the last page */ #define MSG_BATCH 0x40000 /* sendmmsg(): more messages coming */ #define MSG_EOF MSG_FIN diff --git a/include/net/tls.h b/include/net/tls.h index bab5627ff5e3..23601f3b02ee 100644 --- a/include/net/tls.h +++ b/include/net/tls.h @@ -454,6 +454,15 @@ tls_offload_ctx_tx(const struct tls_context *tls_ctx) return (struct tls_offload_context_tx *)tls_ctx->priv_ctx_tx; } +static inline bool tls_sw_has_ctx_tx(const struct sock *sk) +{ + struct tls_context *ctx = tls_get_ctx(sk); + + if (!ctx) + return false; + return !!tls_sw_ctx_tx(ctx); +} + static inline struct tls_offload_context_rx * tls_offload_ctx_rx(const struct tls_context *tls_ctx) { diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 87503343743d..1bb7321a256d 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -8,6 +8,7 @@ #include #include +#include static bool tcp_bpf_stream_read(const struct sock *sk) { @@ -218,6 +219,8 @@ static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes, u32 off; while (1) { + bool has_tx_ulp; + sge = sk_msg_elem(msg, msg->sg.start); size = (apply && apply_bytes < sge->length) ? apply_bytes : sge->length; @@ -226,7 +229,15 @@ static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes, tcp_rate_check_app_limited(sk); retry: - ret = do_tcp_sendpages(sk, page, off, size, flags); + has_tx_ulp = tls_sw_has_ctx_tx(sk); + if (has_tx_ulp) { + flags |= MSG_SENDPAGE_NOPOLICY; + ret = kernel_sendpage_locked(sk, + page, off, size, flags); + } else { + ret = do_tcp_sendpages(sk, page, off, size, flags); + } + if (ret <= 0) return ret; if (apply) diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index d4ecc66464e6..5aee9ae5ca53 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -686,12 +686,13 @@ static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk, struct sk_psock *psock; struct sock *sk_redir; struct tls_rec *rec; + bool enospc, policy; int err = 0, send; u32 delta = 0; - bool enospc; + policy = !(flags & MSG_SENDPAGE_NOPOLICY); psock = sk_psock_get(sk); - if (!psock) + if (!psock || !policy) return tls_push_record(sk, flags, record_type); more_data: enospc = sk_msg_full(msg); @@ -1017,8 +1018,8 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) return copied ? copied : ret; } -int tls_sw_sendpage(struct sock *sk, struct page *page, - int offset, size_t size, int flags) +int tls_sw_do_sendpage(struct sock *sk, struct page *page, + int offset, size_t size, int flags) { long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); struct tls_context *tls_ctx = tls_get_ctx(sk); @@ -1033,15 +1034,7 @@ int tls_sw_sendpage(struct sock *sk, struct page *page, int ret = 0; bool eor; - if (flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | - MSG_SENDPAGE_NOTLAST)) - return -ENOTSUPP; - - /* No MSG_EOR from splice, only look at MSG_MORE */ eor = !(flags & (MSG_MORE | MSG_SENDPAGE_NOTLAST)); - - lock_sock(sk); - sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); /* Wait till there is any pending write on socket */ @@ -1145,10 +1138,34 @@ int tls_sw_sendpage(struct sock *sk, struct page *page, } sendpage_end: ret = sk_stream_error(sk, flags, ret); - release_sock(sk); return copied ? copied : ret; } +int tls_sw_sendpage_locked(struct sock *sk, struct page *page, + int offset, size_t size, int flags) +{ + if (flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | + MSG_SENDPAGE_NOTLAST | MSG_SENDPAGE_NOPOLICY)) + return -ENOTSUPP; + + return tls_sw_do_sendpage(sk, page, offset, size, flags); +} + +int tls_sw_sendpage(struct sock *sk, struct page *page, + int offset, size_t size, int flags) +{ + int ret; + + if (flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | + MSG_SENDPAGE_NOTLAST | MSG_SENDPAGE_NOPOLICY)) + return -ENOTSUPP; + + lock_sock(sk); + ret = tls_sw_do_sendpage(sk, page, offset, size, flags); + release_sock(sk); + return ret; +} + static struct sk_buff *tls_wait_data(struct sock *sk, struct sk_psock *psock, int flags, long timeo, int *err) {